15.05.2008 - Sights set on tanker safety

A private Swedish group has installed a cutting-edge alternative propulsion system on four Croatian newbuildings.

Marinvest of Sweden has taken delivery from Brodosplit Shipyard in Croatia of the fourth in a series of 75,000-dwt long-range-one (LRI) products tankers it claims are among the safest vessels ever built.

The private shipping and investment group has designed and installed an alternative propulsion system that harnesses the ice-class-1A vessels' hydraulic power to keep them moving in the event of main-engine failure.

It is claimed the system, which potentially could avert major tanker disasters, can be operational within around 15 to 20 minutes of a breakdown.

So confident is Marinvest in the so-called power take-in (PTI) system that it has installed it straight from the drawing board without running a prototype.

It is claimed to be the first of its kind for slow-speed two-stroke main engines.

Marinvest says the system has already been fitted on the earlier three tankers and on the Mariann , the fourth sistership that left the yard on 7 May to load its first clean-products cargo.

Developed by Marinvest Engineering and its marine-design guru, Bo Bengtsson, the system links the main shaft to the vessel's Framo hydraulic system normally used to power the cargo/ballast pumps and mooring equipment.

The "take-me-home" device involves a customised shaft/main-engine disconnector. Only five bolts are then needed to connect the hydraulic drive package to the shaft line for the ship to continue sailing.

Manoeuvring of the vessel is still controlled from the bridge by setting the propeller pitch. Trials have produced 2,400 kW and 9.5 knots in moderate weather. A spin-off is having propulsion power available also during engine maintenance.

Marinvest chairman Lars Mossberg says it took a lot to convince the yard but the intention now is to market PTI commercially. Brodosplit has built the disconnectors under licence from Marinvest.

Marinvest technical director Roger Karlsson says the equipment can be easily sized up and down depending on the vessel. Other power sources including electric motors can also be used to power the system.

It is understood the four panamaxes at Brodosplit each cost around $40m. The first three are the Marilee (built 2006), Maribel (built 2007) and Mari Ugland , which was delivered in the first quarter of this year.

The 228.6-metre-long vessels are also innovative in having corrugated bulkheads, which has allowed smooth sides in the cargo tanks and enables easy switching from dirty to clean cargoes, according to Marinvest. The phenolic epoxy-coated tanks have no internal webs or other structures.

Although the ships are not earning more than standard LR1s, Mossberg insists that going forward, charterers will appreciate their flexibility and high 85,659-cbm cargo capacity that can take 55,000 tonnes of naptha, a low-density cargo.

Combined with the design's safety features, Mossberg claims the LR1newbuildings will prove to be "very profitable" vessels for charterers interested in quality. He describes them as the best panamaxes in the market. Thome Ship Management of Singapore is handling the technical management.

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