Cargo operations tanker manual -...

CARGO OPERATIONS (TANKER) MANUAL

CH.15: PRODUCT TANKER OPERATIONS

Rev. No: 1

Date: 20-Feb-15

Page: 1 of 29

Uncontrolled when Printed

15.1. OBJECTIVE

The purpose of this section is to provide masters, officers and crew with guidelines in carrying out

safe, efficient and environmentally friendly operations on board our Clean Product tankers.

15.2. SCOPE

This manual will encompass basic operations on board our Product tankers with special emphasis on

certain cargo operations, sampling, commercial aspects and equipment maintenance standards.

15.3. REFRENCES

ISGOTT

MARPOL Regulations

Cargo Operations Manual (Tankers)

COW Manual

I.G. Manual

Relevant checklists.

Tank Cleaning Guide (Dr.Verwey’s)

15.4. TYPES OF LIQUID CARGOES

To clean the remains of a cargo from a tank or hold and to present it in a condition fit for loading a

different cargo generally involves a considerable quantity of work.

The method adopted for cleaning any liquid cargo residues from a tank depends chiefly upon the type

of cargo involved and its physical and chemical properties.

Some chemical cargoes are extremely toxic and thus dangerous to personnel when exposed to the

fumes. Other cargoes are quick drying and their residues tenacious which can cause a cleaning

problem unless approached in the correct manner. Other cargoes can be water soluble or highly

volatile and require almost no special cleaning process to totally remove their presence from a tank.

Physical removal of some products may be easy but they may leave a strong odour which must be

displaced before the next cargo is loaded. To do this another special process

must be employed.

From the above it can readily be seen that several different processes are required to remove the

large variety of products carried by vessels today.

For the purpose of tank cleaning, cargoes can be subdivided into three categories:

a) Mineral oils

b) Animal, fish and vegetable oils and fats

c) Solvents and chemicals



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The three categories above can be further subdivided into various groupings according to their origin,

physical characteristics and chemical behaviour, especially under varying atmospheric and thermal

conditions.

a. MINERAL OILS

These oils may be divided into four groups based on their degree of distillation or refining:

• Petroleum-based heavy products

• Coal-based heavy products

• Distillates of petroleum

• Distillates of coal

b. ANIMAL, FISH AND VEGETABLE OILS AND FATS

These products can be divided into four groups according to their properties and behavior when

exposed to atmospheric conditions and the effect that oxygen has upon each of the products. Fats

are natural organic products with a freezing point at or below 20°C (68°F). In other respects they are

similar to natural oils. The four groups are:

• Non-drying oils

• Semi-drying oils

• Drying oils

• Water soluble products

It must be noted that some vegetable oils have the property of absorbing or reacting with oxygen from

the air around them. Vegetable oil residues remaining in a tank after pumping out can be affected in

this way. Continuous ventilation preferable by means of mechanically operated power driven fans with

a discharge to the tank bottoms should always be employed. This is especially true when a tank in

which the residues of an oxygen scavenging oil remain and has to be inspected or the deposits

removed from the tank bulkheads and frames. Water soluble products, such as molasses, can be

removed from the tank surfaces merely by washing with cold water.

c. SOLVENTS AND CHEMICALS

Today, chemicals and solvents include a vast and complex range of commodities. There are already

several hundred which can be carried at sea in liquid form. Many of these are entirely harmless, while

others can be extremely dangerous if mishandled. Some chemicals contain enough oxygen to enable

them to burn without additional supplies from the air.

Certain chemicals are hazardous and very dangerous to handle. Some chemicals must never be

inhaled, even in the smallest quantities. Others can be absorbed through the skin into the blood

stream, and reach vital organs.

Obviously, these should never be allowed to come into direct contact with the skin.

Finally, some chemicals are extremely corrosive. Hydrochloric acid is an obvious example, but there

are others. Corrosive chemicals can cause severe burns if they contact the skin or cause blindness if

they enter the eyes. Strong alkalies can have similar effects as those described for acids.

Protective clothing and goggles are essential when working with corrosive chemicals. A complete

chemical resistant suit with helmet and respiratory equipment can be required when handling certain



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obnoxious products. Remember to follow the instructions and all precautionary warnings when

dealing with or handling strong acids or alkalies.

Chemicals and solvents can be divided into two broad categories for the purpose of tank cleaning:

• Volatile liquids with high vapor pressure and low boiling point

• Low volatile liquids with low vapor pressure and low boiling point above 100°C (212°F)

15.5. COMPLIANCE WITH INSTRUCTIONS FOR TANK PREPARATION

In order to minimise bunker consumption, environmental impact and associated costs, vessels will

only clean tanks when necessary.

When the vessel’s Ship Operator makes cargo enquiries, the Master will revert with the anticipated

tank preparations required and these must be confirmed when the cargo is fixed.

Instructions may be issued by the Charterer with regard to the standard of cleanliness and

preparation required and it is important that any specific tank cleaning requirements contained within

a Charter Party are complied with in full. These may be issued as part of the voyage orders, or as a

separate statement.

If tank preparations are required to be carried out within port limits the Master must ensure that local

regulations are complied with, utilizing the local agent as liaison with the port authorities as

appropriate.

Cleaning instructions may also be issued locally by cargo surveyors acting on behalf of the Charterer.

Provided that such instructions are given in writing they must always be complied with.

In the event that compliance with local instructions would result in excessive delay to the vessel, the

work should be commenced and the Marine superintendent advised accordingly.

The Master should also issue a Note of Protest against the delay.

If the vessel receives tank cleaning instructions which conflict with those set out in this instruction, the

Master must contact the Marine Superintendent to clarify the requirements prior to commencement of

tank preparation.

If a detailed cargo specification is not provided at the time a cargo is nominated, the Master must

assume that the highest specification of the nominated grade will be lifted and undertake the tank

preparation required for such higher grade.

It should be noted that it is the ship owner’s responsibility to ensure that a vessel arrives at the load

port with tanks and lines adequately prepared to load the nominated cargo. Charterers are under no

obligation to provide tank preparation guidance or tank inspection / approval prior to loading.

In brief terms, the legal position is that the Charterer may refuse to load a vessel which is considered

unsuitable to receive the cargo. If the cargo is loaded and the cargo is subsequently delivered off

specification, the onus would be on the ship owner to establish that all reasonable preparation work

had been carried out.



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Masters should also use their own judgement and experience in determining the method of tank

cleaning that would be required considering following factors:

o The age of the vessel

o The condition of coating

o The sensitivity of the cargo and its destination.

o The usual ROB after discharging and the possibility of contamination of next grade if

tank cleaning is not planned.

15.5.1. General Guidelines for Tank Cleaning Operations

In order to ensure an “effective” tank cleaning operation the following points should be taken into

consideration:

a) During the washing cycle, the tank bottom should always be kept dry with minimum oil-water

accumulation.

a. This is essential in getting rid of oily residues.

b. If water is noticed to be accumulating, then the washing should be suspended

temporarily to strip the tank dry and then resumed again.

b) Ensure all lines and pumps to be used are well flushed, well stripped and devoid of all

previous residues. Tank cleaning lines should also be flushed/drained to remove any salt

water contained in them.

c) Manifold drains to tanks must be cleaned to remove traces of previous cargo.

d) It may be necessary to steel wool scrub tank heating coils after carriage of certain cargoes.

e) Shadow areas may require extra attention, including areas inside ullaging hatches – any

sediment that accumulates here during cold weather may liquefy during warmer weather and

result in contamination of cargo being carried at the time.

f) Only approved cleaning agents should be used for tank cleaning. The use of an improper

cleaning agent may result in damage to tank coating. Certain lead-based cleaning agents

may even lead to cargo contamination.

g) After completion of line flushing and stripping, the cargo lines shall be drained and knocked to

confirm their emptiness. Plugs should be removed at the pump casings/ strainers and

manifold blanks and valves opened to ensure the same.

h) Certain cargoes such as Aviation Turbine Fuel require the tanks to be rinsed with Fresh

Water and mopped after tank cleaning with seawater. This is normally done by carrying out

man-entry following all safety procedures and then rinsing the tank bottom with a hose.



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i) During tank preparation it is also necessary to take suitable precautions during the mopping

phase as well. For example, mops used for mopping ATF nominated tanks among others,

should not leave behind excessive fibers.

j) Some Charterers might provide the vessel with sufficient quantity of Fresh Water to charge

the slop tank that can be used for two or three tank cleaning operations and then recharged

again. In this case of course the washing is done by a closed cycle method using the fixed

tank cleaning machines.

k) During tank cleaning operations, it must be regularly checked that the tank cleaning machines

are working properly.

l) After the cleaning has been completed, the Master and the Chief Officer should both verify

tank fitness, to guard against one-man error.

m) Information provided to the tank fitness inspector before loading must be factual and

accurate. For example – Tanks machine-washed for 2 hours each, gas freed, fresh water

rinsed, mopped dry, lines, filters and pumps cleaned, ventilated and dried etc.

The Cargo Operations Manual Section 8. 5 / Tank Cleaning Guide Table 1 & Table 2 contained

in Cargo Operations Manual specifies the degree of cleaning necessary between cargoes, except

when the Company or Charterer issues special instructions.

Clarification of the requirements shall be sought through the Marine Superintendent.

15.5.2. Flushing Tank Bottoms and Pipelines in Lieu of Washing

Loading instructions may state that in lieu of tank washing it is acceptable to flush tank bottoms and

pipelines with the product to be loaded, which is then returned to shore using the vessel’s pumps. It is

important that this product is used to flush through every part of the vessel’s pumping system to

ensure that all liquid residue of the previous cargo is removed. In these cases clear agreement must

be reached with the loading installation as to how much product is available and how much will be

loaded into each tank.

15.5.3. Control of Operations

The Master or Chief Officer must always be on board to supervise tank preparation of cargo-related

operations.

The Chief Officer shall complete the Tank Cleaning plan for every tank cleaning operation. The plan

will include stress and trim calculations where applicable and tank or pipeline diagrams will be

clarified by the use of colour. The Chief Officer will present the plan to the Master for review, approval

and signature and will subsequently make copies available to the Chief Engineer, OOW and Duty

Engineer prior to commencing the operation.

The plan should consist of a summary of the operation, including the tanks and pipelines to be

cleaned. It is important that the plan should be simple and easy to understand and a short text and

use of diagrams is preferred. The Plan shall be sent to the Marine Superintendent for review.



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Each OOW and Duty Engineer on watch during the operation will familiarize himself with the plan and

sign it to signify his understanding of it.

15.5.4. Records

Records of all tank preparation operations shall be retained on board. All product carriers may be

required to change grades from dirty to clean and back again dependent on the current market

requirements.

All product carriers will therefore produce and keep on file a formal ‘black to clean’ tank cleaning plan

& schedule OP-TKR-10 & OP-TKR-11 which shall include a plan for washing all pumps and lines and

instructions for washing cargo residues from ullage and sampling ports. The plan shall also outline the

maximum permitted water temperature and pressure.

Amendments made to the plan as a result of experience shall be copied to the vessel’s Marine

Superintendent for review and possible inclusion in Tank Cleaning procedures.

Vessels carrying dirty grades for extended periods shall, so far as is practical, perform a full tank

wash every 3 months to control the buildup of cargo residues and sediment in the cargo tanks which

may hinder the efficient change from dirty to clean cargoes at a future date.

15.5.5. Retained Residues

The stowage of residues and their ultimate disposal must be considered at the planning stage of any

tank preparation operation.

a. Cargo Residues

The ROB quantity must be reduced in accordance with MARPOL 73/78 Regulations. Loading on top

of crude oil or dirty product residues is unacceptable to most Charterers, but the vessel’s Marine

superintendent or Marine Superintendent should be consulted for clarification on an individual voyage

basis. Cargo residues may be discharged to a slop reception facility only on receipt of written

instructions from the

Company or Charterer and must otherwise be retained on board, segregated from the cargo to be

loaded.

b. Tank Washing Residues

Refer to Cargo Operations Manual (Tankers) Ch 12 Pollution Prevention

A vessel may exceptionally be instructed (or granted permission on request) to load on top of oil

residues and small quantities of water remaining after decanting.

Otherwise, the residues must be minimised by decanting clean water and disposed of in accordance

with MARPOL 73/78 Regulations. All disposals must be recorded in the Oil Record Book.



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c. Solid Residues

Scale and solidified oil residues must be removed from tanks whenever gas-freeing for other

purposes presents an opportunity. Oil impregnated residues must not be dumped at sea but bagged

and landed to a shore reception facility.

d. Engine Room Residues

Residues from engine room separators and purifiers must not be transferred to cargo slop tanks

unless this method of disposal is endorsed on the vessel’s IOPP Certificate Supplement and special

permission has been received from the vessel’s Superintendent.

Subject to the endorsement and such permission, ER residues may be transferred to a cargo slop

tank for ultimate discharge to a shore reception facility or, exceptionally, to have cargo loaded on top.

Transfers from the E/R to a cargo slop tank must be recorded in both the Machinery Space Oil

Record Book and Cargo Oil Record Book and it is essential that the times of transfer and quantities

transferred are exactly the same in each book. The temporary connection between the E/R and

cargo piping systems must be fitted only for the duration of the transfer and must be removed at all

other times.

e. Disposal of Residues in Singapore Waters

Strict tank cleaning regulations are in force in the areas around Singapore. All tank cleaning

contractors must be registered with the Singapore Ministry of Environment, and tank cleaning waste

must be disposed of at a facility operated by the Port of Singapore Authority (PSA).

PSA tank cleaning permits will only be granted if the vessel owner or representative can demonstrate

that the waste will be disposed of at an approved facility. The Company will administer such

compliance, and the Master of any vessel planning to wash tanks in the area must notify the vessel’s

Superintendent well in advance of the operation to allow time for a permit to be obtained.

15.6. USE OF INERT GAS SYSTEM

Refer to Cargo Operations Manual (Tankers) Chapter 6 - Inert Gas

The inert gas system, where fitted, must be fully operational during tank washing operations.

If the oxygen content in a tank exceeds 8% by volume, tank washing must cease immediately and the

tank must be purged to less than 8% oxygen by volume before washing may continue.

15.7. TEMPERATURE RESTRICTIONS IN COATED TANKS

The temperature and pressure of washing water in coated tanks must not exceed those

recommended by the tank coating manufacturer and the tank cleaning equipment manufacturer.

Subject to the above restriction It is recommended that the temperature of the washing water is at

least 15°C above the Pour Point of the previous cargo.



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TANK COATINGS

Tanker vessels are usually constructed of mild steel. Parts of the tanks or holds are often coated with

inert coatings to protect them from the more aggressive cargoes. It is common to find product carriers

having their tanks and internals coated to render their surfaces inert and protect them from active

chemical cargoes. Ships which carry the most highly aggressive cargoes have their tanks constructed

from, or covered with, stainless steel sheathing in order that they are rendered passive and will not

corrode excessively under the action of the more active chemicals.

A.THE PURPOSE OF TANK COATINGS

The internal lining of a ship’s cargo and ballast tanks is a common practice undertaken in order to

prevent corrosion, cargo contamination and to facilitate cleaning and sludge freeing.

In crude/refined oil tankers, coatings are intended to prevent corrosion, and reduced scantlings may

be permitted when approved coatings are applied.

B. THE ESSENTIAL COMPONENTS OF PROTECTIVE TANK COATINGS

Any coating - primer coat, body coat or finish - has four essential components:

• Pigment - The pigment contributes color (a coating’s hiding power), and extender pigments are

used to modify viscosity, film strength, hardness, abrasion resistance, protection from ultraviolet rays

and rust inhibitive properties.

• Solvent - The solvent dissolves the resinous vehicle and turns it into a usable form. Solvents control

the viscosity and the way the coatings brush or spray on, settle, level and dry. Typical solvents

include mineral spirits, glycol, ethers and xylene.

• Additives - The additives impart properties which are not contained in the other three components.

Additives serve as agents for drying, wetting, film build, and pigment suspension.

• Vehicle - The vehicle is the most important coating component. It is the binder or “film former” that

binds pigments together and anchors the coating to the surface. The type of vehicle in a coating

determines film thickness, adhesion, consistency, hardness, flexibility, durability, gloss and color

retention, drying time and the coating’s ability to resist corrosive agents such as water, chemicals and

solvents. The vehicles are usually resinous substances. They are cured or transformed in the coating

from a liquid or plastic state to a hard, protective film by one or more the the following methods:

a. Polymerization (chemical conversion through interaction of components) primarily used for

chemical resistant tank lining.

b. Evaporation of solvent (no chemical change in vehicle)

c. Oxidation (absorption of oxygen from exposure to air)

The four components listed above combine into a protective coating integrating physical-chemical

complexes.

Choosing the correct coating requires technical evaluation of many factors. In a typical marine

situation, coatings are selected and applied as a complete system such as the following:

• Prime coat should have anti-corrosion, barrier protection and adhesion properties.

• Body coat(s) should contain film-building and intercoat adhesion properties.

Several systems are available today which incorporate the integrated components described above.



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C. TYPES OF MARINE TANK COATINGS

• Epoxy - Provides good chemical resistance and is available in both low and high build forms. It is

used in both oil and chemical carriers, and is the most frequently used tank coating in today's

market.

• Zinc Silicate - Application of this coating requires special care, but it does give good resistance to

most organic solvents and refined oil products. It does, however, cause slight contamination of

distillate fuel oils and this may preclude its use, for example, with aviation turbine fuel. It is widely

used for solvents and oil products.

• Polyurethane - Occasionally used where slightly superior resistance to organic fatty acids

(vegetable,

fish and animal oils) is required. However, it has less resistance to alkalies than an epoxy.

D. CARE AND MAINTENANCE OF TANK COATINGS

One of the advantages of lined tanks is ease of cleaning, and often water washing is sufficient.

Detergents and steam may also be used without damaging the coating. However, if steam is used to

remove toxic or flammable residues, care should be taken to prevent the steam from blistering the

coating or the steel. If a tank is lined with zinc silicate, the detergents used should be neutral, because

strong alkalies and acids will attack zinc. The normal safe pH range for zinc silicate coatings is

between pH 5.5 and 11.0. Any deviation from this range increases the possibility of softening or

stripping the coatings from the steel.

15.8. TANK PREPARATION FOR FUEL OIL CARGOES

When changing from light to heavy grades, or from low sulphur to high sulphur grades, it may be

possible to minimise tank preparation by ensuring that tanks which are to receive either the heavier

grade or higher sulphur content are very well drained, with minimum ROB quantity. It is unlikely that

the small amount of contamination between the grades will significantly alter the specification of the

grade to be loaded and loading on top of the previous grade may be acceptable.

This possibility should always be discussed with the vessel’s Marine superintendent or Marine

Superintendent and written instructions requested from the Company or Charterer. Where written

instructions are not provided, the Cargo Operations Manual (Tankers ) Section 8.5 Table 1/& 2 Tank

Cleaning Guide must be followed.

15.9. TANK WASHING

Hot water for tank washing is produced either by heating water using the heating coils in one of the

vessel’s slop tanks, or by passing water from the sea through a heater and directly to the tank

washing machines. The heater must be isolated from the cargo system at all times except when

being used for heating water, to prevent it being filled with oil. The following procedure must be

implemented immediately following every occasion that the heater is shut down after use:

- inlet and outlet valves must be shut;

- blanks must be fitted between the inlet and outlet valves and the heater;



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- the heater must be drained;

- a prominent notice must be displayed on the heater to state that blanks are fitted.

Tank cleaning will normally be carried out using the vessel’s fixed tank cleaning system, but in some

vessels washing tanks after dirty cargoes it is necessary to use portable machines in addition to the

fixed machines to remove residues from the shadow sectors of the fixed machines and ensure that

all areas of the tank structure are adequately cleaned.

Tanks must be maintained in an inert condition when using both fixed and portable machines.

Portable machines will be introduced only after the fixed machines have completed a full wash, and

as it will not be possible to inspect the tanks at this stage of the washing program it is important that

the vessel’s records indicate where the portable machines should be placed to obtain their best effect.

The inert gas pressure must be reduced to the minimum positive pressure prior to the portable

machines being placed and sand bags or equivalent must be placed on and around the hose saddles

to reduce the flow of inert gas through the tank wash openings.

Detailed record keeping will assist in identifying the optimum placement of the portable machines and

reduce the time and effort involved.

Machines must be checked regularly to ensure that they are turning properly. Machines are prone to

seizing due to piping scale or rust if they are not used regularly and a spare machine should be kept

ready for use if required.

Tanks must be regularly dipped during washing to verify that the washing water and oil residues are

being effectively stripped. A build-up of water will cause the oil to lie on top of the water and to coat

the tank floor when the machines are stopped and the water is stripped out from beneath the oil.

It may be necessary to ‘wing-out’ portable machines by tying them off on the tank structure to

enhance washing effectiveness. If so, the tank must be gas-freed for entry to permit the portable

machine to be ‘winged-out’ and the tank then re-inerted prior to further washing.

Damage to machines may occur if they are suspended near the tank sides or bottom when the vessel

is rolling and it may be necessary to alter course to reduce rolling in such circumstances. Washing in

heavy rolling conditions is not recommended because the rolling will reduce the effectiveness of

stripping and the tank bottoms will require further washing in calmer conditions.

15.10. TANK WASHING AFTER BLACK OIL CARGOES

Double hull vessels with coated tanks, deep-well pumps and no internal framing are generally capable

of cleaning from Heavy Fuel Oil to Gas Oil with fixed tank washing machines only. However, each

cargo must be treated on its own merits and inspection may reveal that some cargoes require

additional localised cleaning with portable machines, or manual cleaning across the bottom of the

tank. Manual cleaning will be required more frequently in tanks fitted with heating coils.

The amount of washing required to change from black oil to clean will depend on the tank

configuration; the performance of the tank washing machines; washing water temperature and

efficiency of stripping. As a general rule 3 to 4 hours per tank is required with fixed machines followed

by any portable machine washing required.



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Portable machine ‘drop-levels’ should be pre-calculated to maximise the effect on shadow areas

unreachable with fixed machines. Unless the vessel has obtained a degree of confidence from

previous washing, the tank must be gas-freed and inspected after washing to confirm its

effectiveness.

15.11. TANK WASHING AFTER CLEAN OIL CARGOES

In coated tanks, cold water washing is sufficiently effective to clean for quality purposes for all grades,

except after lubricating oils. Cold water should therefore be used unless specified by the Cargo

Operations Manual (Tankers) Section 8.5 Tank Cleaning Guide 1 & 2.

The use of hot water does however expedite tank washing by removing the greasy film associated

with cargoes such as Gas Oil and a short hot wash is useful if preparing tanks for entry.

15.12. WASHING UN-COATED TANKS

Clean products are no longer carried in uncoated tanks. The only significant difference between

washing coated and uncoated tanks after dirty products is that the uncoated tanks will take longer to

reach the required standard of cleanliness.

15.13. OVER-WASHING

Although it is Important to ensure that cargo tanks are sufficiently clean to accept the nominated

cargo, it is equally important to avoid excessive tank washing. Excessive washing causes

deterioration of the tank coatings; accelerates wear of the machines and is an unnecessary expense

due to the bunkers consumed. Experience has shown that there are minimal benefits of extended

washing with fixed machines after an initial 6-8 hours and little further is gained without the use of

solvents, chemicals or manual cleaning. The use of solvents or chemicals will hinder the disposal of

slops at a later date and will only be considered on express request from a charterer.

15.14. USE OF CHEMICALS FOR TANK CLEANING

Tank cleaning chemicals will only be used in exceptional circumstances when required for stringent

cleaning. On these occasions specific instructions will be given in writing by the Charterers. The

Master is to consult the Marine Superintendent prior using the chemicals for washing.

TANK CLEANING CHEMICALS

The action of chemicals used in tank cleaning can be divided into several different categories.

A. SOLVENTS

Solvents are chemicals which dissolve or solubilize other materials or chemicals. In this way residues

and deposits are removed from the tank surfaces, permitting them to be pumped to slop tanks for

disposal.



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B. SURFACE ACTIVE AGENTS (Surfactants)

Surface active agents are usually detergents which act to reduce the surface tension of a liquid and

thus to improve its wetting and cleaning capabilities. They are usually used together with solvents to

produce a cleaning solution which aids in the complete removal of tank residues, such as

hydrocarbons, liquid chemicals, etc.

C.EMULSIFIERS

An emulsifier is a surface active chemical which forms an emulsion of two liquids. One liquid is

present as extremely small droplets, such that particles or globules of it are dispersed and suspended

in the other, i.e., oil-in-water. This suspension often gives a milky appearance.

Emulsification is assisted and sustained by chemicals which consist of molecules with one end

hydrophilic (water seeking) and the other end lipophilic (oil seeking). Utilizing this property, an

emulsifier makes it possible to remove oily deposits with water. Many products acquiesce to this

action, and several different types of emulsifiers are used for removal of a variety of materials.

Emulsification does not usually involve chemical change of either solution but merely suspends

particles of one product within the other, which in turn gives rise to the milky appearance of the

solution.

D. SAPONIFIERS

A saponifier is an alkaline chemical which changes oils and fats into soaps by converting the fatty

compounds into water soluble materials which are biodegradable and easily flushed away from the

surfaces to which they adhere.

Strong alkali solutions (NaOH and KOH) are used as saponifying agents together with a variety of

other compounds in order to deal effectively with the large variety of animal, fish and vegetable oils

being transported around the world today. One minor problem with the above process is to estimate

the exact quantity of saponifier required to neutralize these types of residues. Normally, the

neutralized residues of this process are readily biodegradable.

However, if an excessive quantity of alkali is used, not all of it will be chemically converted in the

cleaning process.

The excess remaining can be harmful to the environment.

E. DREW MARINE DIVISION TANK CLEANING PRODUCTS

The product usually recommended by Drew Marine for removing mineral oil deposits include:

• TC#4TM tank cleaner

A liquid oil solvent emulsifying detergent with hydrophilic properties used for the removal of petroleum

product residues from tanks. TC#4 tank cleaner is used for cleaning crude oils and fuel oils.

• DREW™ TC SEA tank cleaner

A strong emulsifying cleaner for removing heavy petroleum-based stains such as heavy crude oil,

soot,

asphalt and carbon black. Equally effective for cargo and storage tank washing and recirculation,

direct



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injection and manual spray methods. It also works well with agitation from the ship's rolling motion to

clean and gas-free double bottom tanks.

• O&GR™ oil and grease remover

A neutral blend of active cleaning agents and emulsifying solvents. It penetrates and dissolves

grease, oil

and grimy soils forming a soluble mixtue which can be rinsed away with water. It can be used as a

cleaner for metal, parts and tools, painted and unpainted surfaces, decks, bulkheads, machinery,

engines and wherever grease, oil and grimy soils are a problem.

• DREW™ CTC coal tar cleaner

An emulsifying cleaner for removal of coal tar, crude benzene, bitumen and similar substances. It can

be

used for cleaning heavily contaminated metal parts as well as for tank cleaning. Upon sitting, a

solution of water and DREW CTC coal tar cleaner cleaning agent will separate, leaving water at the

top while the cleaner and contaminants sink to the bottom.

• HDE-777TM heavy duty emulsifier

A solvent solution of low foaming detergents and emulsifiers for cleaning petroleum product residues

from cargo and oil tanks or holds. It is also suitable for cleaning oil product residues from the sides of

cargo carrying tanks.

• OSD/LTTM oil spill dispersant

A low toxicity blend of wetting agents and dispersants in a fast penetrating oil soluble liquid vehicle,

specifically designed to disperse oil spills. It can also be used to remove oil residues from tanks and

holds.

OSD/LT dispersant is approved by 12 government bodies worldwide.

• AMEROID® OWS quick separating degreaser

AMEROID OWS quick separating degreaser is a superior solvent emulsifying product for general

engine

room degreasing and for cleaning and gas-freeing of bilges. Its unique blend of surfactants, wetting

agents and solvents results in a product which has exceptional cleaning properties, breaks quickly,

and does not harm the operation of the oily water separators required under the Marpol regulations.

The products usually recommended by Drew Marine for removing the residues of animal, fish or

vegetable oils are

EDGE® heavy duty cleaner and LAC™ liquid alkaline cleaner.

• EDGE® heavy duty cleaner

This cleaner has been formulated specifically to meet the tank cleaning requirements of the marine

industry with special attention to safety and environmental considerations. EDGE cleaner combines

heavy duty cleaning chemicals with fast penetrating and wetting agents for the power required to

remove stubborn soils while remaining sufficiently mild to cause no harm to almost all tank cleaning

surfaces. EDGE cleaner provides an excellent alternative to traditional solvent-based and highly

alkaline cleaners and can be used in a multitude of varying cleaning applications.



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• LACTM liquid alkaline cleaner

This product is a heavy duty liquid alkaline cleaner that can successfully clean non-drying, semi-

drying and drying oils from cargo tanks or holds. It has excellent deodorizing properties and can also

be used in a dilute solution as a final flush in preparation for the next cargo.

Other products available

• MUD CONDITIONER™ ballast tank water treatment

A high weight polymer containing product specifically designed to condition mud and silt bearing

water. MUD CONDITIONER reacts with the mud and silt to form large non-adhering particles which

quickly settle to the bottom of the tank. The result is loosely dispersed particles that can be easily

discharged with the ballast water.

• ENVIROMATE® 2000 general purpose cleaner

A water-based cleaner formulated to meet the marine industry's strict requirements for safety and

performance. With its unique blend of cleaning agents, it is a non-flammable, biodegradable general

purpose cleaner pefect for a broad range of deck, offshore, hotel and galley applications.

• DREW™ BC buffering cleaner

Removes traces of metal oxide stains from zinc-silicate coated tank surfaces. It is used as a final

cleaning

procedure when cargo residues must be removed or when the tank has to be completely chloride or

sulfide free when shipping pure chemicals.

• DREW™ ABD alkaline-based degreaser

A very strong alkaline liquid cleaner applied by injection or recirculation methods, that economically

removes animal, fish, and vegetable oils and fats. Suitable for use on most common metals and tank

coatings.

• DREW™ NBD neutral-based degreaser

A neutral liquid degreaser safe for use on most metals including zinc silicate-coated tanks. An

effective

cleaner for animal, fish and vegetable oils and fats, this product is injected or circulated through

mechanical systems and can be used undiluted for manual spraying. It can also be applied as a final

treatment following hydrocarbon-free cleanings with emulsifying cleaning agents.

• AMEROID® RSR rust stain remover

A liquid combination of rust dissolving acid, emulsifier and passivator for removing rust. Used for

eliminating salt residue, it is injected into the automatic washing system.

• DREW™ AF air freshener

A water-based liquid used to eliminate unpleasant odors in tanks and domestic areas. It is safe to use

on

most common metals and coatings.

Only cleaners listed on the IMO MEPC.2/CIRC.6 can be used and disposed of at sea for cargo tank

cleaning when the cargo residue slops are disposable at sea.



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15.15. PREPARING FOR DRY DOCK OR MAJOR REPAIRS (REFER TO CARGO OPERATIONS MANUAL / 8.10)

15.16. FRESH WATER RINSING

When preparing tanks to load cargoes such as Vacuum Gas Oil, Wax Distillate or Low Sulphur Gas

Oil, it may be necessary to “rinse” with fresh water any tank that has been washed with salt water or

has previously contained salt water ballast in order to remove the salt. It is not necessary to use large

quantities of fresh water to achieve this but it is important that all parts of the tank structure are

reached and that tanks are well stripped and lines well drained after the rinse.

15.17. WATER FLUSHING PUMPS AND LINES

For tank cleaning or gas freeing to be effective it is important that all oil and oily residues are removed

from pumps, pipelines, strainers, etc.

To facilitate line washing the contents of lines should be drained into a cargo tank or stripped into a

slop tank immediately after tank inspection on completion of discharge. Valves or vacuum breakers

must be opened to admit air.

Lines are washed by pumping from the sea or by introducing tank washing water into the system. It is

important that a full bore of water flows through the pipelines and that all sections of the system and

the pumps themselves are flushed. The vessel’s Cargo Operating Manual should be consulted to

identify possible problem areas such as ‘dead ends’ of pipelines. The water is then discharged to a

slop tank either on board or ashore.

In some vessels it is necessary to wash cargo drop lines into the cargo tanks, which must be done

before the tanks are cleaned. In the majority of other cases it is recommended to wash up cargo lines

and drop lines, not down them.

Deck lines which cannot easily be washed conveniently by circulating the washing water through the

piping system may be washed by introducing water through a blank flange, drilled and fitted with a

suitable hose coupling. It is important that a valve is used to control the water out-flow of the section

being washed so that the lines remain filled with water during washing.

When cleaning for dry docking or repairs, the water remaining in lines after line washing should be

dropped into a suitable tank and the valves should remain open to permit ventilation.

15.18. HEATING COILS AND ASSOCIATED LINES

Heating coils are to be pressure tested, blown through and repaired,

if required, immediately prior to:

• Loading a cargo which requires heating;

• Tank repairs (to avoid leakage of product or fumes into the tank under repair);

• Gas-freeing for drydocking or major voyage repairs;



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On every occasion that cargo tanks are washed and gas-freed for entry, for any purpose, the

opportunity must be taken to carry out close inspection and observation of heating coils under

pressure test.

Under no circumstances must steam be applied to heating coils while personnel are inside the tank.

Observation must be from the deck only. If leaks are evident, steam must be shut off before personnel

enter the tank and any further tests which may be necessary to pinpoint the location of a leak must be

carried out with air or water.

15.19. ELIMINATION OF WATER PRIOR TO LOADING SPECIFIC PRODUCTS

Some products are very sensitive to even small quantities of water remaining in tanks and pumping

systems after washing. The Tank Cleaning Guide identifies these products and great care must be

taken to remove all free water from the tanks and pumping system prior to loading.

• On completion of line washing and draining, open all cargo line valves and vacuum breakers to

drop line contents back into the tanks;

• Drain cocks or plugs in cargo pumps and their associated air vessels, vacuum breakers,

strainers and by-passes must be opened and all parts of the pumping system drained;

• Where fitted, fixed eductor systems must be blown through with air, valves opened and lines

drained into the tanks;

• The tank washing line must be drained and fixed tankwash machine valves opened to drain all

parts of the tankwash line into the tanks;

• “Low points” of pipelines must be identified and efforts made to blow through the relevant

sections of line to the nearest cargo tank or drain point;

• All valves and drains must remain open during the tank mopping process;

• Any list placed on the vessel to assist in draining tanks and lines must be removed prior to

mopping to allow any pools of water lying on stringers and stiffeners to drain down to the tank

floor;

• The Inert Gas Deck Seal overboard line must be checked to ensure that it is clear and valves

are fully open;

• The Inert Gas Deck Seal level must be checked to ensure that no water (or other fluid, if used)

will be carried over from the seal into the cargo tanks when the tanks are re-inerted prior to

loading;

• Heating coils must be blown through and isolated to guard against any leakage from the coils

into the cargo tanks.

15.20. PURGING CARGO TANKS WITH INERT GAS (In addition to Cargo Operations Manual (Tankers) Section 8.8)

Purging of tanks which are already inerted will be carried out during tank preparation operations to:



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• maintain the oxygen content of a tank atmosphere at or below the required 8% x vol. during

washing;

• reduce the hydrocarbon content of a tank atmosphere to or below 40% LFL for cargo quality

purposes, prior to loading;

• reduce the hydrocarbon gas content of a tank atmosphere to below 2% x vol. prior to

introducing air into the tank when gas freeing.

15.21. REDUCING HYDROCARBON GAS CONTENT FOR CARGO QUALITY CONTROL

This operation is often described as “Gas-freeing for Quality Purposes” but this description is

misleading as tanks are not “gas freed” in the conventional sense.

In inerted tanks, the atmosphere is diluted by purging with inert gas until the hydrocarbon gas content

throughout the tank is less than 40% LFL.

In tanks which are not inerted, the atmosphere is diluted by fresh air until the hydrocarbon gas

concentration throughout the tank is less than 40% LFL.

15.22. GAS FREEING CARGO TANKS - GENERAL PRINCIPLES

The term “gas-freeing” refers to the process of diluting and displacing a cargo tank atmosphere with

fresh air. A tank is “gas-free” when sufficient fresh air has been introduced into the tank to lower the

level of any flammable, toxic, or inert gas to safe limits.

Gas-freeing may be carried out by using the vessel’s IG fans drawing fresh air, or by use of portable

fans, or both.

Gas-freeing fans shall be examined prior to each use for signs of friction or loose parts. It is

particularly important to check the bearing housing for signs of overheating and the guards for

security of fitting and clearance between the guard and blades. If any defect is found the fan must be

taken out of service and repaired prior to next use.

Effective dilution of the tank atmosphere is dependent upon a turbulent air flow and the penetrating

ability of the incoming stream of air to break up and displace layers of heavy gas in the bottom

regions of a tank. Efficient gas-freeing is dependent upon the air flow penetrating all areas of the tank

between widely separated air inlets and atmosphere outlets, and the ideal configuration is to have the

inlets and outlets located at opposite ends of the tank.

Regardless of the method used or length of time taken, the tank atmosphere will always be sampled

by remote gas testing carried out from a safe location prior to any entry into the tank.

Remote gas testing will be carried out:

- using the appropriate instrument for the task;

- a minimum of 10 minutes after the fans are stopped, to ensure that the tank atmosphere has

stabilised prior to testing;



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- at widely separated locations within the tank;

- at a minimum one third, one half and two thirds of the tank depth;

- in each compartment of the tank, if sub-divided by wash bulkheads.

15.23. GAS-FREEING FOR CARGO TANK ENTRY AND COLD WORK (refer to HSM Section 2.2.3)

15.24. GAS-FREEING FOR CARGO TANK HOT WORK (refer to HSM Section 2.2.3)

15.25. CARGO TANK INSPECTION

Responsibility for the suitability of cargo tanks to load the nominated grades lies with the Master, but a

loading terminal representative or independent cargo surveyor acting on behalf of the Charterer may

be required to inspect the vessel’s tanks. Requests for such inspections must be accepted, but they

do not relieve the Master of his responsibilities.

Vessels fitted with an inert gas system must arrive at the loading port with the oxygen content in all

cargo tanks below eight percent (8%), unless contrary instructions are contained in the voyage

orders.

A request by a terminal representative or cargo surveyor for the vessel to gas free one or more cargo

tanks for inspection should be refused unless the Charter Party contains a clause providing for such

an inspection.

In the event of any dispute regarding the need for such an inspection, the Master must contact the

vessel’s Marine superintendent for clarification and if the decision is that the Master should permit the

inspection, he must request written instruction to proceed with de-inerting and gas freeing.

After gas-freeing for inspection, loading may only commence into reinerted tanks with an oxygen

content of below 8% and the loading may be concurrent with continued inerting of other tanks.

15.26. PRODUCT CHARACTERISTICS

The quality characteristics of petroleum products are measured by a number of standard laboratory

tests which either measure an absolute quality of the product in question (density, sulphur content) or

show behaviour of the product under particular conditions.

An explanation of the following characteristics can be found in ISGOTT

Cloud Point

Density

Flash Point

Pour Point

Viscosity

Reid Vapour Pressure

True Vapour Pressure



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15.27. PRODUCT GUIDANCE

a. Naphtha / Clean Condensate / LDF

a) Naphtha (Full Range/Light/Heavy) Virgin Naphtha (VN)

b) Light Distillate Feedstock (LDF)

c) Chemical Feedstock

d) Plat former Feed Cat. Reformer Feedstock

e) Clean Condensate Natural Gasoline

f) Pentane Plus Straight Run Gasoline

g) Straight Run Benzene (SRB)

Comments:

Heavier grades of LDF can tolerate a small contamination by Jet A1, DPK, Solvents, or lighter grades

of LDF. As Feedstock’s tend to be unrefined they may put other products off-spec on odour, corrosion

test, etc

Naphtha & LDF cannot tolerate any lead whatsoever and therefore should be buffered from leaded

cargoes by the prior carriage of another product. Washing after Unleaded Motor Spirit is required due

to oxygenates which may adversely affect the processing of Naphtha

LDF nominated for certain ports may require loading into "well drained" tanks rather than washed in

order to avoid chlorine.

If in any doubt as to whether condensate is “clean” of “dirty”, contact the vessel’s Marine

superintendent and Marine Superintendent.

b. Aviation Gasoline (Avgas)

a) Avgas Aviation Gasoline

b) Aviation Spirit

Comments:

Av-Gas has a high lead content; a flashpoint within the ambient temperature range, and is usually

dyed. It has a strict specification for aviation purposes and cannot tolerate contamination by water or

any grade other than very small quantities of Motor Spirit.

c. Leaded Motor Spirit

a) Premium Motor Spirit (PMS)

b) Regular Motor Spirit (RMS)

c) Motor Gasoline Mogas

Comments:

Leaded Motor Spirits are frequently dyed and may contain surface-active additives. Any measurable

contamination with unleaded products (over 1%) will cause the Research Octane Number (RON) to



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drop. Where contamination between grades is unavoidable the lower RON grade must be

contaminated with the higher.

Tanks will require washing after carriage of Marked/Dyed Gas Oil or Kerosene.

d. Unleaded Motor Spirits and Motor Spirit Blending Components

a) Regular Unleaded (ULMS)

b) Premium Unleaded (PULMS)

c) Superplus (SUMS) Methyl Tertiary Butyl

d) Ether (MTBE)

e) Toluene Reformate

f) Cat Cracked Spirit (light/heavy)

g) Alkylate

h) Steam Cracked Spirit (light/heavy)

Comments:

Thorough water washing of tanks after leaded products and draining of pumps/lines is essential to

remove any lead contamination. Tanks will require washing after carriage of Marked/Dyed Gas Oil or

Kerosene.

e. Solvents

a. Special Boiling Point Solvents (SBPS)

b. Rubber Solvent Unleaded Cleaning Spirit

Comments:

These products are unleaded and have flashpoints within the ambient temperature range. Due to a

considerable variation within grades guidance on cross-contamination will be specific. No

contamination by other products can be tolerated.

f. Jet Fuel / Aviation Kerosene

a) Jet A-1 Aviation Turbine

b) Kerosene (ATK)

c) Avtur Kerosene Water White

d) Dual Purpose Kerosene (DPK)

e) Avcat High Flash/Low Freeze

f) JP5 High Flash/Low Freeze

g) JP8

h) TS1 (Russian) RT (Russian)

Comments:

These products are unleaded and have flashpoints from 28°C upwards. They have a strict

specification for aviation purposes and cannot tolerate contamination from water or any other grades

except for very small quantities of un-dyed Gas Oil or Kerosene.



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If loading on top of un-dyed Gas Oil or Kerosene, the tank must be well drained or educted to reduce

ROB to less than 0.1% of the Jet / ATK to be loaded.

Water haze in Jet / ATK can cause filter blockage by ice particles. Water will eventually settle out if

left standing but this is not possible at most installations. Great care must be taken in ensuring that

tanks, lines and pumps are free from water before loading or discharging.

Hand mopping is essential for Aviation Turbine Kerosene (JP5) for the U.S. Forces, as any water will

leach out an antiicing additive mixed with JP5.

Similar UK Ministry of Defence requirements may be advised at the time of loading.

g. Un-dyed Premium & Regular Kerosene

a) Regular Kerosene Blending Kerosene

b) Premium Kerosene Odourless Kerosene

c) Kerosene Feedstock Superior Kerosene

d) Burning Oil (US / Canada) Lighting Kerosene

e) Stove Oil (US / Canada)

Comments:

These products are similar to Jet and ATK but can tolerate small quantities of water and will not

require mopping after water washing.

h. Dyed Kerosene (with the same characteristics as Un-dyed Kerosene)

The very small quantity of dye used in dyed kerosene can put Jet/ATK or other un-dyed Kerosene off-

spec for colour. Tanks which previously contained dyed kerosene must be washed and educted prior

to loading un-dyed products.

i . Un-dyed Gas Oil

a) Automotive Gas Oil (AGO) Odourless Gas Oil

b) Automotive Diesel Oil (ADO) Odourless Gas Oil

c) Feedstock

d) No. 2 Furnace Oil (US / Canada) Mud 47/20 Dieso

e) Drilling Oil

f) Extra Light Fuel Oil (ELFO) Inferior Kerosene

g) Navy Distillate

h) Distillate Marine Diesel (Pale) DERV HS Diesel Oil

i) Navy Distillate

Comments:

Unleaded with minimum flashpoint requirements, varying between 55.5°C and 65.6°C. The level of

acceptable contamination by lighter distillates such as Kerosene depends on the flashpoint. Although

lead free, very small quantities of lead can be tolerated.



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Water haze, produced by pumping fuel containing free water, can deposit a water layer in terminal or

domestic customers’ tanks. When such water contains salt it presents a potential corrosion hazard if

allowed to accumulate. This problem has been particularly associated with hazy ELFO used for

domestic heating and is unacceptable.

Although water haze in Gas Oil supplied as fuel for gas turbines is not in itself harmful to the operation

of the engine, its presence indicates that sodium (which can cause severe pitting of the turbine

blades) may be present in an unacceptably high concentration. Care must be taken to ensure that

tanks are well drained or educted prior to loading and all water is drained from cargo pumps and lines.

If Gas Oil is hazy on loading, water will generally settle out during the voyage. If water dips show free

water prior to discharge, receivers should be advised and where possible agreement reached for the

settled water to be stripped ashore before the bulk discharge of the cargo. This will minimise the risk

of re-hazing the oil from the mixing action of the ship’s pumps. If stripping ashore is not possible then

transfer of the water to a slop tank on board should be considered.

j. Marked or Dyed Gas Oil

(with the same characteristics as Un-dyed Gas Oil)

The very small quantity of dye used in dyed Gas Oil can put un-dyed Gas Oil (and Jet/ATK and other

un-dyed Kerosene) off-spec for colour. Tanks which previously contained dyed Gas Oil must be

washed and educted prior to loading un-dyed products.

k. Ultra Low Sulphur Gas Oil

Ultra Low Sulphur Turbine Gas Oil Low Sulphur Marine Gas Oil

Comments:

These products have a very high specification with a sulphur level below 0.5% and cannot tolerate

any contamination with salt water (sodium). Vessels may be instructed to rinse tanks with fresh water

prior to mopping.

l. Crude Oil / Dirty Condensate

The “Crude Oil - Carriage Temperature and COW Requirements” Spreadsheet must be consulted

prior to loading any Crude Oil or Condensate. Although specific tank preparation and carriage

instructions may be given by the Charterer in the voyage instructions, in the event of any conflict

between the voyage instructions and the information given in the spreadsheet, the Master must

contact the vessel’s Marine superintendent to query the voyage instructions and obtain confirmation

of the Charterer’s requirements obtained.

m. Lubricating Oil

Lubricating Oil cannot tolerate water and tank preparation is to be the same as for Jet/ATK. For

quality reasons, Lubricating Oil is often loaded, carried and discharged in non-inerted tanks due to the

possibility of contamination from IG. If no written instructions regarding the use or non-use of IG are

provided when the cargo is nominated the Master must contact the vessel’s Marine superintendent to

request specific written instructions.



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n. Wax Distillate/Vacuum Gas Oil / Cracker Feed

These products cannot tolerate sodium and tanks which have been washed with seawater must be

rinsed with fresh water prior to draining tanks and lines. Vacuum Gas Oil may occasionally be loaded

on top of very light crudes and condensates without washing. On these occasions, specific

instructions will be given by the Company or Charterer.

o. Medium & Heavy Fuel Oils

a) Medium Fuel Oil (MFO) 100-225 cSt@50°c

b) Heavy Fuel Oil (HFO) 380 + cSt@50°c (including High Sulphur Atmospheric Residue)

Comments:

These products have a significantly lower pour point than Low Sulphur Fuel Oil (LSFO) and only

minimal contamination by LSFO can be tolerated. Tanks containing LSFO must be well drained and

educted to minimise ROB prior to loading MFO/HFO.

Washing is generally required for loading MFO/HFO after Crude Oil as any significant contamination

by Crude Oil will reduce the flash point of the MFO/HFO, but the need for washing may be avoided if

the following conditions can be met:

• Crude Oil ROB is less than 0.1% of the volume of MFO/HFO to be loaded into each tank.

• The tanks nominated to receive MFO/HFO are purged to reduce the hydrocarbon level to below

the LFL.

• The fuel oil is maintained at the maximum permissible temperature during the voyage in order to

correct the Flashpoint.

If no specific instructions are provided when the cargo is nominated the Master must contact the

vessel’s Ship Operator to obtain clarification of the tank preparation required.

p. Low Sulphur Fuel Oil (LSFO)

a) Low Sulphur Fuel Oil (LSFO)

b) Low Sulphur Atmospheric Residue

Comments:

LSFO has a sulphur content of 1.0% or less and is frequently manufactured with a sulphur content

very close to the specification limit. Only minimum contamination from other Fuel Oils can be

tolerated. Stringent hot washing must normally be carried out before loading Low Sulphur Fuel Oil

after Crude Oil.

q. Light Fuel Oil (LFO)

a) Light Fuel Oil (LFO) Fuel Oil 30/35

b) Furnace Fuel Oil 50/50 No. 4 Fuel Oil



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c) U.S. Navy Special Burner Fuel

Comments:

LFO has a low viscosity and wax can cause serious problems with some LFO grades. Tanks which

previously contained other Fuel Oils or Crude Oil must be washed with the highest temperature water

permitted by the tank coating and tank washing machine manufacturers respectively, in order to

remove waxy residues.

The need for washing after carriage of MFO/HFO may be avoided if the following conditions can be

met:

- MFO/HFO ROB is less than 0.1%;

- the previous cargo had a low wax content.



r. Low Sulphur Wax Residue (LSWR), Vacuum Gas Oil

(VGO) and Waxy Distillate Cargoes.

LSWR has made the headlines recently in the shipping industry, primarily due to its very high pour

point property and waxy nature and the difficulties experienced in shipping these cargoes.

VGO and Waxy Distillate have similar properties to LSWR and the following advice applies to these

cargoes also.

Cargo Properties of LSWR

a) Pour Point – Approx 48 deg C

b) Flash Point - >90 deg C

c) Density at 15 deg C – Approx 0.9

d) Viscosity at 80 deg C – 445 CST

e) Average load port temperature – About 45 to 50 deg C.

f) C/P requirement for temperature to be maintained on the

g) Voyage and during discharge – Above 65 deg C.

General issues in carrying this cargo The carriage of high pour point cargoes like LSWR carries some

risks. These risks are increased when the cargo is carried from areas of high ambient temperature to

areas of low ambient temperature (below pour point of cargo), and in areas of extreme weather.

Solidification is the main risk and the following problems could occur if care is not taken with planning:

• Solidification in the tanks if not heated / stripped properly

• Solidification in the pipelines – when the cargo comes up on deck it cools down rapidly resulting

in the formation of a coating on the inside of the pipe work. This will get thicker and thicker as

the flow rate slows and could well end up blocking the lines completely.



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• This solidification in the pipelines will be worse in the case of small drain lines.

• If loaded to 98% in tanks, the cargo may enter the IG lines, purge lines, flame screens, vent

lines and PV valves due to the sloshing effect in heavy weather and there is a good chance

that these will be blocked which could in turn cause hull/tank damage. In addition there is a risk

of inhibiting high or hi-hi alarms if these become coated with the product

• The cargo entering and blocking the tank cleaning machines.

• A high remaining on board (ROB) quantity can be expected due to all above factors. Apart from

the commercial aspect, this high ROB will cause further problems at the next load port. The

ROB quantity usually solidifies around and blocks the bell mouth area making it extremely

difficult to load the next cargo since it takes considerable time for the fresh cargo to melt this

solidified cargo.

• It may not be possible to use the fixed gauge system for ullage monitoring as they are prone to

getting blocked if used.

• The Pressure Gauges at the manifold may become unreliable as they do not show any

pressure due to Solidification of cargo in the small line leading to them.

• The ODME is prone to getting fouled with the LSWR cargo during decanting operation on

ballast passage.

Procedures to be adopted while carrying LSWR on any class of vessel

The following procedures are to be adopted by the vessels prior to, during and after every LSWR

cargo carried:-

The maximum ullage to be loaded in any cargo tank should be limited to 90%.

All the IG lines, purge lines, venting lines and PV valves must be checked by hammer (use a

nylon headed mallet) test to ensure no blockage. If any doubts exist in any of the pipelines

then they must be opened up to confirm no blockage exists.

The floats of high level alarms must also be checked prior to every cargo operation to ensure

these are not blocked.

There should be a minimum of four MMC tapes on board prior to the carriage of LSWR.

These must be checked to ensure they are working satisfactorily. The number and status of

these tapes must be reported to the Superintendent prior the carriage of LSWR. Also, the

MMC tapes in use must be cleaned after every ullaging to ensure the sensors are not blocked

with cargo.

Careful planning of ballasting operation will have to be carried out with regards to the ballast

level in the tanks, above DB levels, so as not to allow cold ballast water to come in contact

with the tank-top and thereby cool the cargo above.

Leave tank valves open while transiting tropical waters – perhaps leave head trim on for one

day for draining forward main lines then stern trim to drain after lines.

While in tropical waters try and drain manifolds as best as possible down the main deck drain

(using the Wilden pump if practical)

Discharge plan should be carefully drawn up taking into account the following considerations:



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• Discharge even tanks with a good stagger between each set of tanks (can be odd tanks

• When first set at stripping level (try to make it 2w) stop discharge from 4w, 6w and strip

2w tanks, deck line and manifold.

• Repeat procedure for 4w, then 6w.

• So far as practicable, discharge each tank out of its respective manifold, avoiding use of

the manifold crossover. This would be the best option as it would allow direct stripping of

each manifold to shore using the small bore stripping line (this can be used in this

configuration as there would be no dead ends)

• If using each tank's manifold is not possible (as the downside is of course that manifold

connections would have to be changed after each set of wing tanks and the trade off

between increased out-turn (also for vessel decreased risk of line blockage) and excess

pumping time would have to be agreed by the terminal) then:

a) Avoid using the design small bore stripping lines. Strip the main lines and manifolds

through the manifold crossover (this will probably result in a relatively high line

content ROB);

b) When stripping through the slop crossover allow air pressure to build up before

opening the valve to try and 'shoot' the cargo up and into the slop line; and 3) Send

flushing oil through each line as it is completed and return to the slop tank.

• Discharge will be slower than normal in any case. This is because each set of tanks will

need to be s stripped before moving on to the next set. Normal procedure of stripping

back to the slop tank while maintaining bulk discharge would best be avoided as the slow

flow of cargo through the line to the slop tank in the cold temperature may result in a

blockage

• Ballast can be commenced in adjacent tanks as soon as cargo is out.

• Once even tanks are out and ballast is going in, start on the odd tanks and repeat the

whole procedure.

• Make sure any stoppages for stripping are minimized

• Strip over the top; as previously mentioned, do not use any small bore lines

• Subject to restrictions in the charter party heat the cargo to above 70 deg C prior to arrival

at the discharge port.

• Give thought to heat the non-discharging tanks if the temperatures are observed coming

down to 65 deg C. (note this will slow the discharge a little but not too much, no more

than running ballast pumps.

A Risk Assessment must be carried out for every cargo operation assessing all the

problems set out above. In particular the possibility of carrying out cargo operations without

an operational SAAB system must be explored here. Also careful planning should be carried

out to drain all lines without exception.



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Ballast Passage: 1) Leave all the valves open. 2) Air blow and use the Wilden pump to clear

lines back to slop tank.

As the ODME is prone to get blocked and damaged if it is allowed to come into contact with

LSWR cargo, care should be taken to stop the decanting well before the oily mixture reaches

ODME, even though this may add up the slops quantity. This is necessary in case tank

washing has to be performed for the carriage of next cargo.

12. The carriage of LSWR is only allowed in Summer seasons as below:

As a general guide as to whether the cargo is being carried or discharged in Winter or

Summer the world can be divided into the following zones: -

Northern Hemisphere (North of the Tropic of Cancer).

• Summer, 1 April to 31st October

• Winter, 1 November to 31 March.

Southern Hemisphere (South of the Tropic of Capricorn).

• Summer, 1 October to 30 April.

• Winter, 1 May to 30 September

Tank cleaning guide must be consulted prior and after the carriage of LSWR with regards to

the tank preparation

s. Carbon Black Feedstock

Carbon Black Feedstock is a high density black oil cargo with a low viscosity and pour point but prone

to solid deposits when the cargo is allowed to cool therefore requiring heating during carriage. The

Master must request specific instructions for carriage from the Marine superintendent if not provided

with the voyage instructions.

High ROB after discharge is common and every effort to load a small quantity of cutter stock after

discharge should be made in order to flush the lines and tank bottoms.

If the next cargo is a clean product then hot water washing as soon as possible after discharge is

required. Crude ships will generally be given crude oil as the next cargo and it is imperative that a full

COW be carried out to remove any solid deposits from the previous cargo. In order to be effective

particular attention should be paid to the bottom washing cycle with frequent multi-point dipping to

ensure the removal of solid deposits.

t. Carriage of Other Products

If products not contained in the Tank cleaning Guide are to be loaded, special instructions for tank

cleaning will be sent to the Master by the vessel’s Marine superintendent either with the loading

orders or as a separate document.





Rev. No: 1

Date: 20-Feb-15

Page: 28 of 29


15.28. BLENDING/COMMINGLING OF CARGO

This instruction describes the standing orders and lines of directions for the Master in the event that

the Charterers requires or instruct the vessel to blend / commingle the cargo products presently

being on board the vessel.

Procedure

Blending or commingling is mostly associated with oil cargoes in bulk and cargo interests may wish

to commingle or blend the cargoes loaded on different dates and/or at different places and / or with

different specifications.

Blending / Commingling may take place when:

A. two or more different grades of cargoes are requested to be blended / commingled on

board at same or at different ports;

B. cargo from one terminal / port is blended / commingled on board with the cargo loaded

from another terminal / port;

C. different cargo grades or cargo grades loaded at different terminals / ports are requested

to be blended / commingled on board the vessel while it is enroute.

Blending / Commingling instructions may be included in the Charterers “Voyage Orders”,

but should this operation be requested, the Master must refuse to perform any such

blending or commingling unless very clear approval and instructions have been received

from the Tanker Operation Department.

The blending / commingling of any oil cargo products on board may affect the specifications of

the cargo already loaded and the vessel may be held liable under any Bill of Lading already

issued for such cargoes.

The same liability may arise under the Bill of Lading being issued for the second, third, fourth and so

on parcels loaded. Whilst a remark can be inserted in the Bill(s) of Lading for the parcels loaded and

drawing the attention to the requested blending / commingling of the cargoes, should the cargoes

have been loaded in “apparent good order and condition”, there will be no basis for clausing which

throws doubt on the apparent order and condition.

There may be complications with regard to the date and place of shipment stated in the issued

Bill(s) of Lading because, if these are different, a single Bill of Lading should not be issued.

If the Charterers request for blending or commingling of the cargoes loaded, the Tanker Operation

Department will require a Letter of Indemnity directly from the Charterers indemnifying the Company

and the Master of the vessel for any cost and / or consequences related to such request for blending

/ commingling of the cargo’s.

In the event that blending / commingling of the cargoes on board is requested to be carried out while

the vessel is enroute after having departed loadport(s), the Master shall request and ensure that all

issued Bill(s) of Lading are being marked:



Rev. No: 1

Date: 20-Feb-15

Page: 29 of 29


“Cargoes have been Blended / Commingled on board the Vessel”

In the event that such request is not being fulfilled, the Master must approach the Tanker Operation

Department immediately for advice and clarification.

Cargo operations tanker manual -...

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