Indra Nath Bose Head – Vessel Performance Management,

The Great Eastern Shipping Co. Ltd.,

Tanker Operator Conference Making Money in a Tough Market

Mumbai 5th February 2015

Technical Measures - retrofits;

Hull and Propeller Maintenance

Vessel Performance Management

Becker Mewis Duct device are known to provide an energy savings of around 5% depending on hull profile;

It channels the water flow more accurately over the propeller to offer more bite and so create better efficiency;

Fins also add pre-swirl to reduce rotational loss.

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5 Source: ABS

Modeling and tank test cost can be spread across ‘sister’ vessels;

Manufacturers are building up a database of ‘standard’ ship types that could benefit most from this feature, and thus the cost for this would be less as the design work has already been concluded.

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Means of validation:

◦ Model tests

◦ Full-scale trials

Retrofitting takes 4 days;

The return of investment of the MEWIS Duct is strongly

depending on:

◦ Number of vessels in the ship series

◦ Bunker prices

◦ Operation profile of the vessel (sailing days and speeds)

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Source: Schneekluth Website

Source: Ship energy efficiency measures – status and

guidance by ABS

10 Source: ABS

Means of validation:

◦ CFD

Easy to retrofit and maintain;

Mitsui claim that they have installed more than 1700+ of

its Propeller Boss Cap Fins.

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Kappel Propellers (KAPPEL, Denmark, now MAN Diesel & Turbo);

CLT Propellers (SISTEMAR, Spain, evolution of TVF Propellers);

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Source: MAN PrimeServe

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Source: MAN PrimeServe

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Thanks to the end plates the pressure and suction side do not

communicate, inhibiting the formation of tip vortexes and allowing the generation

of thrust along the entire blade and the reduction of pitch. They have smaller

diameter.

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Propeller efficiency reaches the highest value when thrust generated on a

propeller blade continuously increases from the boss to the tip.

In a CLT Propeller (Contracted and Loaded Tip Propeller) this theoretical

principle is realized by fitting an end plate at the blade tips.

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Higher efficiency (between 4 - 8%)

Fuel saving => Reduced emissions

Higher top speed => greater operational flexibility

Inhibition of cavitation and of the tip vortex

Less noise & vibrations

Lower pressure pulses

Lower area ratio

Greater thrust

Smaller optimum propeller diameter

Better maneuverability.

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• Fitted on Bulk Carrier

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• Retrofitment does not pose any problem • The hub will have the same geometry as that of current

propeller

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The payback period will depend on ◦ Vessel’s operational profile, and

◦ Bunker price.

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Finally these propellers are compatible with most of the Propulsion Improvement Devices currently offered, thereby allowing even further efficiency gain.

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The frictional resistance is governed by the wetted surface (main dimensions and trim) area and the surface roughness of the hull consisting of

◦ roughness of steel hull,

◦ coating,

◦ added roughness due to fouling

◦ and coating degradation.

The initial roughness is taken as 120 µm which is the approximate roughness value for a typical new building though some ships are delivered with a very low surface roughness at around 75 µm.

Average Hull Roughness (AHR) of ≈65 μm is very good,

AHR of 150 μm is standard and

AHR > 200μm is sub-standard.

Historical records have shown that even with good maintenance practices average hull roughness can increase by 10 to 25μm per year, depending on the hull coating system, even when fouling is not included.

As a rule of thumb, every 25 µm (25/1000 mm) of hull roughness increase corresponds to 0.7-1% of increase in fuel consumption due to additional propulsion power requirement.

Source: Jotun A/S

Source: Jotun A/S

Source: Jotun A/S

Source: Jotun A/S

It is a layer of microscopic organisms including bacteria and diatoms and the slimy substances they produce. Often referred to as a ‘slime layer’, microfouling can usually be removed by gently passing a finger over the surface.

Large, distinct multicellular organisms visible to the human eye, such as barnacles, tubeworms, mussels, fronds of algae and other large attached or mobile organisms.

Use of Formal Checklist - for evaluation of products

Longivity

Suitability

Product Features

Efficacy

Maintenance – Repainting / Repairing

Fuel Saving

Environmental concerns

Cost

Guarantees being provided by Manufacturer

1. Propeller Polishing every 6 months;

2. Use of superior anti fouling paints and control of hull roughness.

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It is a system for gathering data related to ship operation viz. trim, draft, main engine, aux. engines, steam plant, voyages, navigation etc.

Categorizing the same for different operating conditions viz. At Berth, Manoeuvring, Sea Passage and Anchor / Waiting etc.;

Comparing the data against given baseline values viz. model test results / sea trial results.

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It generates new information system expressed as: ◦ Deviations from baseline conditions. ◦ Trending of the deviation from the baseline. ◦ Diagnostic of vessel performance based on fuel

consumption.

It assists the shipboard staff in taking early and immediate action in preventing wastage of fuel;

It allow onshore management to see the data in a variety of graphs, tables and trend charts which assist in finding optimal operating characteristics;

Helps in benchmarking the performance of each vessel and trade;

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Helps in making sound investment decisions;

It delivers the necessary insights for improving a ship's operational efficiency;

It helps in backing up efficiency claims with hard evidence;

With the knowledge that the data provided is accurate and free from human error, analysis work can be carried out and decisions made confidently.

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Suitable energy saving devices can be beneficial;

Controlling hull roughness and maintaining propeller in polished condition helps in energy saving;

Performance monitoring provides insight for enhancing energy efficiency.

Thank You