Oil Tankers

A.A. B. Dinariyana

Jurusan Teknik Sistem PerkapalanFakultas Teknologi Kelautan – ITS Surabaya2013

ME 091304Teknik Bangunan dan Konstruksi Kapal II

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Tankers

Gas tankers Liquefied petroleum gas (LPG) Liquefied Natural gas (LNG)

Crude oil tanker Product tankers

Oil products like gasoline, kerosene, naphtha, diesel oil, lubricating oil, bitumen

Vegetable oil, etc Chemical tankers

Acids, alcohol, petrochemical products, etc

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Gas tankers

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Crude oil tankers

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Product tankers

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Chemical tankers

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Chemical tankers

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Standard size of crude oil tankers

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BKI – definition

"oil" means petroleum in any form including crude oil, refined products, sludge and oil refuse.

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Crude oil

"crude oil” means any liquid hydrocarbon mixture occurring naturally in the earth whether or not treated to render it suitable for transportation and includes: crude oil from which certain distillate

fractions may have been removed, and crude oil to which certain distillate

fractions may have been added

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Cargo arrangement

Every oil tanker of 600 tdw and above must comply with the double hull requirements of MARPOL 73/78, Annex I, Reg. 13 F.a) for which the building contract is placed on or after 6

July 1993, orb) in the absence of a building contract, the keels of

which are laid or which are at a similar stage of construction on or after 6 January 1994, or

c) the delivery of which is on or after 6 July 1996, ord) which have undergone a major conversion:

i. for which the contract is placed after 6 July 1993; or

ii. in the absence of a contract, the construction work of which is begun after 6 January 1994; or

iii. which is completed after 6 July 1996.

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Double hull requirements for oil tankers of 5 000 tdw and above

The entire cargo tank length is to be protected by a double side (wing tanks or spaces) and double bottom tanks.

Double side Wing tanks or spaces are to extend either

for the full depth of the ship's side or from the top of the double bottom to the uppermost deck, disregarding a rounded gunwale where fitted.

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Double hull requirements for oil tankers of 5 000 tdw and above

Double side They are to be arranged such that the cargo tanks are

located inboard of the moulded line of the side shell plating, nowhere less than the distance (w )which is measured at every cross section at right angles to the side shell as specified below:

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Double hull requirements for oil tankers of 5 000 tdw and above

Double bottom At any cross-section the depth of each double bottom

tank or space is to be such that the distance h between the bottom of the cargo tanks and the moulded line of the bottom shell plating measured at right angles to the bottom shell plating is not less than:

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Double hull requirements for oil tankers of 5 000 tdw and above

In the turn of bilge area or at locations without a clearly defined turn of bilge, where the distances (h) and (w) are different, the distance (w) shall have preference at levels exceeding 1,5 h above the baseline. For details see MARPOL 73/78, Annex I, Reg. 13 F (3) (c).

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Double hull requirements for oil tankers of less than 5 000 tdw

Double bottom

Oil tankers of less than 5 000 tdw are at least to be fitted with double bottom tanks or spaces having such a depth that the distance (h) complies with the following:

In the turn of bilge area and at locations without a clearly defined turn of bilge the tank boundary line shall run parallel to the line of the midship flat bottom.

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Limitation of cargo tank length Irrespective of the ship's deadweight, the length of

cargo tanks of oil and product tankers measured between oil tight bulkheads is not to exceed 10 m or the values listed in Table 24.1, whichever is greater.

BKI Vol. II, Section 24, Table 24.1

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Limitation of cargo tank length

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Limitation of cargo tank length

Where the tank length exceeds 0,1 L and/or the tank breadth exceeds 0,6 B calculations must be carried out in accordance with BKI Vol. II, Section 12, C.1. to examine if the motions of liquids in partially filled tanks will be in resonance with the pitching or heeling motions of the vessel.

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Ship arrangement

Cargo tanks are to be segregated by means of cofferdams from all spaces which are situated outside the cargo area.

A cofferdam between the forward cargo tank and the forepeak may be dispensed with if the access to the forepeak is direct from the open deck.

and the forepeak air and sounding pipes are led to the open deck and portable means are provided for gas detection and inerting the forepeak.

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Ship arrangement

Machinery spaces are to be positioned aft of cargo tanks and slop tanks; they are also to be situated aft of cargo pump-rooms and cofferdams, but not necessarily aft of the oil fuel tanks.

Any machinery space is to be isolated from cargo tanks and slop tanks by cofferdams, cargo pump-rooms, oil fuel tanks or ballast tanks.

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Arrangement of doors, windows and air inlets

Entrances, air inlets and outlets and openings to accommodation spaces, service spaces, control stations and machinery spaces must not face the cargo area.

They are to be located on the transverse bulkhead not facing the cargo area or on the outboard side of the superstructure or deckhouse at a distance of at least 0,04 L* but not less than 3 m from the end of the superstructure or deckhouse facing the cargo area.

This distance need not exceed 5 m.

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Superstructures

According to Regulation 39 of LLC 66, a minimum bow height above the waterline is required at the forward perpendicular.

Where the bow height is obtained by freeboard and sheer, the sheer is to extend for at least 15 per cent of the length Lc of the ship measured from the forward perpendicular.

Where it is obtained by freeboard and fitting a forecastle, it is to extend from the forward perpendicular to a point at least 0,07 Lc abaft.

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Superstructures

Machinery and boiler casings are to be protected by an enclosed poop or bridge of not less than standard height, or by a deckhouse of not less than standard height and equivalent strength.

Machinery and boiler casings may be exposed if there are no openings giving direct access from the freeboard deck to the machinery and boiler space.

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Superstructures

A weather tight door may, however, be permitted in the machinery and boiler casing, provided that it leads to a space or passageway which is as strongly constructed as the casing and is separated from the stairway to the engine room by a second weather tight door of steel or other equivalent material.

Openings in superstructure end bulkheads are to be provided with weather tight closing appliances. Their sills are not to be less than 380 mm in height. Reference is made to the respective requirements of the LLC 66.

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Anchor equipment

The anchor windlass and the chain locker are considered a source of ignition.

Unless located at least 2,4 m above the cargo deck the windlass and the openings of chain pipes leading into the chain locker are to be fitted at a distance of not less than 3 m from the cargo tank boundaries, if liquids having a flashpoint (closed cup test) not exceeding 60 °C are intended to be carried.

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Cathodic protection

Impressed current systems and magnesium or magnesium alloy anodes are not permitted in oil cargo tanks. There is no restriction on the positioning of zinc anodes.

When anodes are fitted in tanks they are to be securely attached to the structure. Drawings showing their location and the attachment are to be submitted.

Aluminium anodes are only permitted in cargo tanks of tankers in locations where the potential energy does not exceed 275 Nm. The location and position from the bottom of the tank should be taken into consideration

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References

MARPOL 73/78/97

Peraturan Biro Klasifikasi Indonesia Volume II, Edition 2006