Ocean-going ships, presently in an excess for the amount of cargo to be lifted, increasingly steam at slower speeds in order to save expensive fuel oil bunker costs; better that than to be laid up reckon shipowners.

Photo courtesy of Maersk Line

The problem is that large marine diesel  engines are not designed to operate below 85% power for long periods without harmful effects; effects best ameliorated by getting lubricating oil of the right specs. After a quick look at lubricating oil solutions, a handy little device to check cylinder performance is spotlighted.

Marine Diesel Engines & Slow Steaming

Experts at Castrol Marine drew on OEM reports and their own engine performance tests to analyse the effects of slow steaming on engine performance, finding that the oil-feed rate as well as a lower engine operating temperature had a bearing on the amount of corrosion caused on piston rings and cylinder liners.

At lower loads, the cylinder oil’s feed rate is reduced, making less available BN (Base Number) constituents to neutralise acids and reducing the protective oil film thickness. This can mean lubricants degrade, increasing the potential for acidic corrosion and increased wear rates. Lower engine operating temperatures that come with slow steaming also further increase the risk of cold corrosion.

The conclusion drawn by Paul Harrold, Castrol’s Technology Manager, Marine & Energy Lubricants: “Higher BN lubricants provide greater neutralisation and hence better corrosion protection across the fuel sulphur range during slow steaming.”

While 40 BN cylinder oil suits vessels predominantly operating in ECAs, cylinder oils of 70 BN and above are better suited to those vessels regularly slow steaming, to ensure piston ring packs and liners remain in good condition.

With slow steaming likely to cause damage to cylinder components it seems apposite to mention a portable, inexpensive gadget made in Sweden  – Prisma Teknik’s ‘Bohman DEC-Tester'  –  which provides a simple, yet useful tool for  assessing cylinder condition.

Bohman DEC-Tester

Prisma Teknik’s ‘Bohman DEC-Tester': Photo courtesy of Prisma Teknik

Air (at standard 6 − 8 bar) is injected into the cylinder via the DEC-Tester, which the manufacturers say is an improvement on similar methods as it controls the pressure as well as the flow of air.

The unit is connected to the indicator valve of a cylinder whose piston has been cranked near TDC and will immediately show a reading on a scale 1 – 10. For example, a recently overhauled cylinder might show a reading of 1.5, another unit with a reading of 7.4, would indicate the need for investigation, while a reading at the top end of the scale normally suggests serious valve problems exist.

The tester can be used on both auxiliary and main diesel engines with a bore diameter of from 160 mm to 460 mm for both continuous follow-up of cylinder condition as well as for troubleshooting.

Worth its 3 kg weight in gold for the solutions it provides, the DEC-Tester comes for just 862 Euros.

The Volvo Penta IPS steerable pod drive introduced in 2004, is well known in recreational applications. The subsequent introduction of larger drives up to the IPS1200 model and the availability of light commercial ratings for the drives has widened the appeal of this type of propulsion system to workboat applications.

Caption: Alu Marine’s new Lightning 1200 Pilot Boat, designed by Geronimo Naval Design
office powered by twin IPS 450s cruises at 30 kn and has a top speed of 35 kn.
Image Credit: Geronimo Naval Design

In its publicity material Volvo Penta is claiming performance improvements of an increase in top speed of up to 6 kn and an improvement in fuel consumption of up to 30 per cent at cruising speed! While these claims may well be under perfect circumstances even if the improvements are only half of claimed, the benefits are considerable. Taking this a step further the considerable benefits in a recreational application become major through life operational cost savings in a commercial environment. What is saving hundreds of dollars annually in pleasure use becomes many thousands of dollars per year when considering the high number of hours a vessel is used in commercial applications.

A number of workboats and patrol boats have started to use IPS and recently Alu Marine, France introduced a new Lightning 1200 Pilot Boat, designed by Geronimo Naval Design office powered by twin IPS 450s. The 39 ft (12 m) LOA hull has a beam of 13.6 ft (4.2 m) and draft of 1.8 ft (0.55 m), draft, including IPS propulsors is 3.2 ft (1 m). Twin Volvo Penta in-line six cylinder D6 engines of 5.5 litres are each rated at 330 mhp (243 kW) at 3,500 rpm and power the smallest IPS drive in the IPS programme (of three drive sizes). The cruising speed is 30 kn and the fuel consumption is given as being 11.3 US galls per hour (43 l/h) per engine. The fuel capacity is 350 USgalls (1320 liters), sufficient for 15 hours operation at cruising speed: the top speed is 35 kn.

Caption: The Volvo Penta IPS450 has a D6 engine rated at
330 mhp (243 kW) at 3,500 rpm
Image Credit: Volvo Penta

In the April 2012 Journal of Ship Hull Performance from the Hydrex Group, international
specialists in underwater hull treatments, a White Paper called the 'Ship Propeller
Maintenance: Polish or Clean, explains how to save up 15 per cent of propulsion fuel
costs without harm to the environment.

Caption: USS_Arleigh_Burke: average periods between full cleaning of the US Navy
DDG51 Arleigh Burke class destroyers is five years with interim cleaning including
propellers at about six month intervals.
Image Credit: US Navy

It describes how a propeller is most efficient when its surface is smooth. Immersed in water,
within hours it starts to loose its smoothness and become rough. The rougher a propeller is
allowed to become before it is remedied, the more rapid further roughness occurs in an ever
worsening spiral.

There are a number of reasons why or the speed at which a propeller becomes rough and get rougher in service. Split
into groups, there are two man made sources, material of manufacture and improper polishing or
cleaning. Static in water sources are marine fouling, corrosion and calcareous deposit (chalk
layer) as a secondary effect of corrosion protection. In service sources are impingement attack
(small water bourne objects), cavitation erosion and mechanical damage from impact with foreign
objects, flotsam etc.

Despite the reason, the effect must be remedied and there is no remote method of assessing
propeller surface roughness. A manual check must be made either by a diver or in drydock:
obviously the former is faster and cheaper. Failure to check regularly causes loss of speed with an
increase in fuel consumption the consequence

This was accurately quantified in trials by the US Navy on the destroyer USS McCormick which
indicated that about two-thirds of the increase in fuel consumption due to fouling was due to
propellers fouling. After 226 days out of drydock the average fuel consumption required to
maintain a given speed had increased to 115.8 per cent of the consumption with a clean bottom.
After cleaning the propellers (only), the fuel consumption dropped to 105.5 per cent. Thus in
seven months the propellers alone were responsible for a 10 per cent increase in fuel consumption.

Caption: Trials by the US Navy on the destroyer USS McCormick indicated that about two-thirds
of the increase in fuel consumption due to fouling after 226 days was due to propellers fouling.
Image Credit: PD-US Navy

Average periods between full cleaning of the US Navy DDG51 Arleigh Burke class
destroyers is five years with interim cleanings (including propellers) at about six month
intervals, however rates of fouling depend very much where and how the vessel is
being used.

The conclusion of the White Paper is that "a little and often" is preferable to "seldom and severe"
when it come to propeller cleaning. To illustrate the point a case study of a 442 ft (134 m) cruise
ship is given. The propellers were cleaned by one of the ship's crew who was a diver, using a
rotating brush alone - no grinding or polishing disc was required. As the propellers are often
cleaned, the fouling was not very heavy so both propellers could be cleaned in a total of 40
minutes. The resultant fuel savings were calculated at 6 per cent. In the first 30 hour trip, the fuel
savings were estimated to be $2,142. Had the propeller been cleaned by an outside company it
would not have cost more than about $2,000. Since the fuel saving would accumulate until the
next cleaning - in one or two months, the savings are obviously substantial.

Caption: Cleaning a propeller with a brush and abrasives. The ship's two propellers were cleaned
in approximately 40 minutes.
Image Credit: Hydrex

Merchant ships in MARPOL Vl Emission Control Areas (SECA) have to burn either low sulphur fuels/distillates; or heavy fuel oil plus an exhaust gas scrubber; or LNG, in order to comply with engine exhaust gas emission regulations – it’s as simple as that. The first two fuels are readily available worldwide, but not liquid natural gas (LNG). The past week saw minds concentrated, in locations half a world apart, on ways to make LNG with its cleaner exhaust gas emission characteristics, and (likely) lower price more widely available.

LNG Bunkering in Europe

A few days ago the European Sea Ports Organisation (ESPO) brought together in Zeebrugge, Belgium, a group of fifty professionals to consider safety aspects of LNG bunkering, where it became clear that a number of ports within the European SECA area are already well advanced in setting up LNG bunkering stations, with supply mainly by special bunker barges.

Clearly though, Norway, which incidentally has large natural deposits of LNG, leads the field in its take-up of the fuel. At present, there are 25 LNG fuelled ships operating in the Baltic and North Sea Emission Control Area.

Trond Giske, Norway's Minister of Trade and Industry, describes the LNG bunkering infrastructure problem as something of a conundrum – bunker distributors do not want to set up a supply network until there is sufficient demand from shipping, while shipping cannot change to LNG without a supply infrastructure. He referred to this as a ‘chicken and egg’ problem; solved in Norway by the allocation of funds from the national budget to clean energy development company Enova to set up the necessary natural gas infrastructure.

 Meanwhile, DNV hosted the annual Process and Asset Risk Management Conference (PARC) in Brussels that focussed attention on LNG opportunities, with news that Antwerp, Zeebrugge and Ghent add to the list of European ports making an investment in LNG bunkering facilities, joining those in the Netherlands, Sweden, Finland and Poland.

Photo courtesy of Lloyd's Register

LNG Bunkering in South East Asia

If Europe is leading, Asia-Pacific regional bunker hub Singapore aims to catch up. Its Maritime and Port Authority (MPA) established a joint industry project (JIP) managed by DNV earlier this year to investigate the operational feasibility of LNG bunkering in Singapore with finance from MPA’s ‘MINT’ fund (the Maritime Innovation & Technology Fund).

Just as in Europe, the key barrier to more widespread adoption of LNG as ships’ fuel was recognised to be an immature bunkering infrastructure. It was mainly to address this issue that the MPA set up its JIP project, which includes participation by a household-name list of shipping industry stakeholders.

Dr. Anthony Barker, General Manager for BG Singapore Gas Marketing, and Chairman of the JIP steering committee said: “This JIP is a school book example on how industry and regulators can work closely together to accelerate the implementation of new technologies and industry solutions that one single player can not accelerate alone.”

Despite that though, resolution of the LNG bunkering infrastructure ‘chicken – egg’ problem may best be hastened, as it has been by LNG leaders Norway, with a financial push from an interested government.

Wing-in-Ground (WIG) craft development took a firm step forward with the recent announcement that two Korean companies –  Daewoo Shipbuilding & Marine Engineering (DSME) and Wing Ship Technology Corp –   are to co-operate to make production of WIG craft a viable operating and commercial proposition. The offshore support vessel market is in their sights, and they also have plans to develop a 200-seat WIG craft for military use.

Wing Ship Technology successfully produced their 50-seat prototype WSH-500 (classed by Lloyd’s Register) late last year with $6.3 million funding assistance from DSME.

Wing-in-Ground Effect Craft WSH-500: Photo courtesy of Wing Ship Technology Corp.

WIG Concept & Maritime Safety

A WIG craft is a vessel capable of operating completely above the surface of the water on a dynamic air-cushion. The 'ground effect' refers to what a pilot (commonly passengers too ) feels when landing a large aircraft – just before touchdown it’s as if the plane wants to go on and on – due to the cushion of air trapped between the wings and the runway. Hence ‘aerodynamic ground effect’.

Presently there are no safety standards in place for WIG craft, although the International Maritime Organisation (IMO) did publish interim guidelines ten years ago. The United States Coast Guard, in conjunction with the Federal Aviation Administration and the IMO (a pairing that underlines the WIG concept’s intersection with both air and sea) say this is a work in progress.

Propulsion & General Particulars WSH-500

Gas Turbine Engine by MTT & Shaft Prop: Photo courtesy of MTT

US-based MTT Corp was contracted to design the special 1,400 hp gas-turbine propulsion systems for the WSH-500 to drive customised 10 ft propellors developing 4,800 lbs thrust.

German naval architect Hanno Fischer, a pioneer in WIG craft development, brought his expertise to bear on the Korean initiative by Wing Ship Technology (founded in 2007) to develop the WSH-500, and the builders say they intend four vessels for delivery in the current year at a price of about US$ 6.7 million each for the basic configuration.

Principal particulars are as follows:

• Passenger capacity: 47 passengers and 3 crew
• LOA: 28.5 m (93.5 ft)
• Breadth overall: 27 m (88.6)
• Height: 6.7 m (22 ft)
• Displacement: 17.1 tons
• Construction material: aluminium alloy
• Propulsion: MTT gas-turbine: 2 x 1,400 Turbo-shaft/Prop
• Cruising speed 100 kts (on trial achieved 73 kts in GE mode)
• Fuel: 1 tonne capacity, consumption about 250 kg/hr
• Range: 300 (162 nm)
• Cruising height: 1 to 5 m (3.3 to 16.4 ft) with safe landing at all times

WIG Craft Advantages

High speed transportation without the need of an airport is the great advantage. Speeds of a light aircraft or helicopter are capable of being matched, but require less redundant systems as the craft can land quickly and smoothly in an emergency.

The designers reported good stability and minimal pitch and roll during sea trials of the WSH-500 in air-borne operating mode, assuring passenger comfort.

DSME vice president Y.Y. Koh said WIG craft are well suited to meet the needs of the offshore market, considering that they were safer and more economical than widely-used helicopters.

The European Commission proposed new rules a few days ago requiring ships of the European Union (EU) to be recycled (scrapped) only in facilities that are approved as safe for workers and environmentally sound; while shipowners would have to apply for an ‘Inventory Certificate’ of hazardous waste on board (reduced if deemed necessary) before delivery to a listed shipbreaker. Hazardous waste in lder ships contains many hazardous materials, including asbestos, polychlorinated biphenyls (PCBs), tributyl tin and large quantities of oils and oil sludge.

Shipbreaking on Beach, Bangladesh: Photo credit Wiki CCL Stéphane M Grueso

Environment Commissioner Janez Potočnik said: "Although the ship recycling sector has improved its practices, many facilities continue to operate under conditions that are dangerous and damaging. This proposal aims to ensure that our old ships are recycled in a way that respects the health of workers as well as the environment. It is a clear signal to invest urgently in upgrading recycling facilities.”

Ship Recycling – Asia the Preferred Destination

According to the current legislation (the Waste Shipment Regulation) EU flagged ships going for scrap can only be dismantled within a member state of the Organisation for Economic Cooperation & Development  (OECD). This legislation is almost systematically circumvented by EU flagged ships, say the Commission ( on cost-saving grounds) and currently most EU controlled ships are dismantled in Asia (India, Pakistan and Bangladesh), usually through the ‘beaching’ method and with significant environmental and health impacts. The new proposal aims to address the shortcomings of this legislation and to allow, under strict conditions, the recycling of EU-flagged ships in these Asian non-OECD countries.

In 2009 ship dismantling data revealed:

Ship Recycling Yards and Shipowners – New Responsibilities

Some of the requirements to be met by the ship recycling facilities are stricter than those foreseen by the Hong Kong Convention on Ship Recycling (stalled, perhaps for some years, as ratification by member states is tardy) whose foundations are built on by the EU proposal. The proposed new regulations will ensure European-flag ships are better traced for accountability, and will guarantee that the waste resulting from dismantling (and any hazardous materials it contains) is managed in an environmentally sound way.

For shipowners, the proposal a system of survey, certification and authorisation for large commercial seagoing vessels that fly the flag of an EU Member State, covering the whole life cycle of the ship from construction to operation and recycling.

To ensure compliance, the proposal requires ship owners to report to national authorities when they intend to send a ship for recycling. By comparing the list of ships for which they have issued an inventory certificate with the list of ships which have been recycled in authorised facilities, authorities will be able to spot illegal recycling more easily. The European Commission also intend that sanctions proposed in the new regulations will also be more specific and precise.

For full information on the European Commission proposals click here.

The new Wärtsilä low speed, electronically controlled X35 has successfully passed its Factory Acceptance Tests (FAT).

Caption: The Wärtsilä 6X35 during Factory Acceptance Trials at the
Yuchai Marine Power Co., Ltd. (YCMP), China factory.
Image credit: Wärtsilä

Two six cylinder X35 engines successfully completed the Factory Acceptance Trials last month in two separate facilities, one at 3.MAJ Engines & Cranes, Croatia, and the other at Yuchai Marine Power Co., Ltd. (YCMP), China. The trials were witnessed by representatives of the Classification Society, the shipbuilder, and the shipowner.

The new engine series was originally introduced in May 2011 as the RT-flex35, following these good results, the X35 engine series as it is now known, is henceforth available for introduction to the market.

It is a completely new engine that, together with the Wärtsilä X40, will cover the small-bore end of the market and fills a gap in a segment where Wärtsilä has not been present for a number of years.

Caption: Specifications of the X35 series.
Image credit: Wärtsilä

The X series engines has a bore of 350 mm and features an extra long stroke of 1,550 mm offering improved fuel economy and greater operational flexibility. In addition, the optimum propeller requirements can be realized within the low engine speed of the rating field lying between 142 to 167 rpm. During the 6X35 tests, the low fuel consumption characteristic of the engine was verified with the predicted brake specific fuel consumption (BSFC) returning a value of 176g/kWh, within the usual 5 per cent margin under IMO Tier II conditions.

Caption: Cutaway drawing of a 6X35 showing internal parts.
Image credit: Wärtsilä

Oil fuel and lube oil testing proves its worth (let the buyer beware) advises chemical analysis specialist companies Lintec and Intertek, telling a few days ago of their joining hands to provide a service to help guard ship operators world-wide against the perils of using off-specification oils. A case study illustrates their point.

The entire fleet of a Hamburg-based shipowner was placed on Lintec’s chemical screening programme. On one of the ships, on long-term charter, a sample fuel analysis revealed that bunker fuel containing DCPD (Dicyclopentadiene) and Styrene had been taken on board; the charterer being duly informed of the inherent risks to the ship’s engine that might arise from this bunker stem. Soon, operational difficulties, including blocked oil filters, were reported to the extent that the fuel had to be pumped out and replaced at the next port of call. Further lab analysis was done to determine the exact levels of contamination, with results that persuaded the charterer to accept financial liability for all costs incurred.

Oil Fuel Bunker Barge: Photo credit Wikipedia CCL DKrieger

Fuel Oil Contamination – a Global Problem

Oil fuel contamination is not limited to off-the-map bunkering ports. Another chemical analysis specialist in the field, US-based Guardian Marine Chemical has stated that samples of Low Sulphur Fuel Oil with DCPD levels in the range 200 ppm to 600 ppm, and Styrene from 500 ppm to 2,200 ppm were found at bunker stations on the Gulf coast of the US. At these levels, and lower, vessels have reportedly suffered serious engine damage, not only blocked filters, but also at greater cost, blocked purifiers, broken piston rings and seized fuel pumps.

Interestingly, Guardian Marine points out that high levels of these contaminants had exclusively been found in LSFO samples, whereas strangely enough, heavy fuel oil (high sulphur content) was free of DCPD and Styrene in that particular area. They thought a low sulphur cutter stock containing refinery waste might have been used to blend the fuel down to a MARPOL-compliant <1.5% Sulphur content.

In news of their liaison Lintec/Intertek say that an internet-based laboratory management system, a feature of their ‘ShipCare Services Programme’, offers an efficient and speedy process for testing bunker fuel in order to circumvent damage to ships’ engines, costly down-time and repairs, as well as to help avoid costly exhaust-gas emission related infringements. Reports of fuel analysis come with full engineering comments, and helpfully, in the event of off-specification fuel, recommendations by Intertek’s industry experts.

Roll on roll off freight ferry Seatruck Performance was launched from the Flensburger Schiffbau-Gesellschaft (FSG) shipbuilding yard at Flensberg, Germany, earlier this year, the third of the same class whose initial delivery (Seatruck Progress) was acclaimed Hansa’s ‘Ship of the Year 2011’. These compact, fuel-efficient ships for British operators Seatruck Ferries are for service between Irish Sea ports and have interesting features.

Launch – Seatruck Performance: Photo credit FRG

Design Features

Maximum length as well as draft of the newbuildings was entirely dictated by port usage restrictions at one of the main operating ports – Heysham, on the North-West coast of England – and accordingly the quartet of new ships are exactly 142 m (465.9 ft) LOA with a loaded draft of 5.2 m (17.06 ft).

Despite this restriction, the design with the bridge placed above the bows yields a surprising 2,166 lane meters for carriage of unaccompanied trucks, trailers and Ro-Ro casettes on four loading decks including the tank top.  Away with bottlescrews and chain lashings! On these decks heavy vehicles are instantly secured using the ingenious SAT system manufactured by Scandinavian Ro-Ro Construction which mechanically joins the trailer to the ship’s deck for the sea passage.

The shipyard claimed a 30% reduction in fuel consumption for this design against similar carriers, probably key in winning the ‘Ship of the Year’ award, mainly achieved through propulsion enhancements and a refined hull design as will be seen.

Propulsion

Main propulsion system is by two MAN 7L48/60-CR medium speed diesel engines, each with an output of 8,000 kW operating through Renk gears to drive twin 4-bladed high-skew variable pitch propellers.

A cone-shaped shaft deflection cap fitted to the trailing edge of the MAN propellor hub caps which in conjunction with a hydro-dynamically optimised Costa propulsion bulb boosts propulsion efficiency, while at the same time cavitation damage to the rudder is prevented. The rudder itself is a twist-flow design by FSG, turned by a rotary vane steering gear from Rolls Royce. Service speed is 21 kts, then for docking assistance there are two (controllable pitch) Wärtsilä transverse thrusters.

Electrical needs are met by two diesel generator sets from MHI, with emergency backup from a MAN diesel set capable if necessary of feeding 400k VA to the on-board grid. Fuel is warmed by an exhaust gas exchange heater, if necessary by a separate oil-fired thermal heater.

A SAM Electronics MCS 2200 automation system monitors and controls operation of the whole machinery with more than 700 installed sensors and control elements, enabling full control from bridge or engine room.

All four ships of these outstanding specialist ships are classed by DNV and built under their supervision.

Fishing trawler Vellee sank in the Little Minch channel west of Scotland’s Isle of Skye on a calm and clear night last summer apparently without being holed, leading MAIB (UK Marine Investigation Branch) investigators to conclude in their recent accident report that the loss probably resulted from a catastrophic failure of internal sea water piping or fittings – most probably the outcome of advanced electrolytic corrosion.

Fishing Trawler Vellee: Photo courtesy of Skipper JimmyT

Evidence of Corrosion as Probable Cause

A few days before the trawler’s final voyage (from Fraserburgh north-about mainland Scotland to Kilkeel on the east coast of Ireland for better fishing in the Irish Sea) repairs to the main engine were needed, and engineers discovered that two of the eight cylinder liners of the main Kelvin TASC8 engine were badly corroded by electrolytic action; thickness reduced by as much as 85% in some places. An electrician called to investigate, thought that a missing earth bonding strap on the main engine and an earth fault on communications equipment, could have caused the corrosion. It remained unknown whether electrolytic action had afflicted any other parts of the vessel and the wooden-hulled 19.8 m (65 ft) LOA fishing boat duly left port.

Cylinder Head Liner Corrosion Vellee: Photo credit MAIB

Bilge Alarms and Main Seawater/Bilge Pump System

The loss of the Vellee that night came without warning of the deluge as no bilge alarms sounded. Regulations require a minimum of two independently wired engine room bilge alarm systems be installed, and the report notes that those on board had not been tested  or maintained for fourteen months.

On account of the trawler’s main sea water/bilge pump system (designed capacity 420 litre/minute) a fairly large volume of sea-water was permanently circulating whenever the main engine was running. The outflow running continuously either to deck wash or to overboard discharge; if allowed to run dry this pump would seize up. For fairly obvious reasons the report did not favour this kind of arrangement, mainly because it increased the risk of flooding if any part of the system were to leak or burst.

MAIB Accident Report – Conclusion and Recommendation

Amongst other things the MAIB report mentioned the fact that an inoperable auxiliary engine reduced potential pumping capacity, and that emergency pumping systems were not maintained, tested or kept ready for use.

The crew –  skipper, mate (his son) and the deck-hand –  were safely rescued from a liferaft by helicopter. MAIB recommended the owners improve the planned maintenance and inspection regimes on all vessels in which they hold an interest.

The extensive and meticulous full report report on the loss of fishing trawler Vellee is available as a PDF file from MAIB.