Page 45: of Maritime Reporter Magazine (April 2022)

TECH FEATURE PROPULSION when one of the jets sustained major the jet room where you can clean it up damage, AG EMS was faced with a and continue with your repairs. You dilemma. “These things always seem don’t have to go outside, onto the water, to happen at the height of the season,” where everything is wet, dangerous and

Claus laughs, “never in the winter- slippery. It’s all so much easier and safer time! So we had two options: one was now for our ship engineers.” to repair the old SII version, taking on board the lead time and expenditure of ‘It’s an easy process’ sourcing all the necessary spare parts, Kongsberg’s own ? gures suggest that or to change the complete system to the upgrading from SII to S-4 waterjets will next-generation Kongsberg Maritime improve a vessel’s acceleration by 15%,

Kamewa S-4 waterjets.” its propulsive ef? ciency by 7%, and its

The lead times for repair or replace- steering and reversing manoeuvrability ment were almost identical, so there was by 25%, equating to a reduction in to- no discernible advantage in that respect tal fuel consumption of approximately to remaining with the existing arrange- 25%. Calculations of this kind are all ment. More than that, however, was the very well in abstract terms, but custom- realization that no progress would be ers investing in a pair of new S-4s can be made by merely repairing the damaged forgiven for requiring hard proof. In the

SII. “We wouldn’t have had any better case of AG EMS and Nordlicht, this in- outcome later on; we’d still be looking volved taking a series of comprehensive at the same operational status,” Claus performance measurements both before said. “So in that moment, it was a case of and after installation of the waterjets – weighing up whether to invest €150,000 a procedure which Claus characterises to stick with our old system, or spend as straightforward. “You cut out the aft more money but improve literally every- plate and insert the new adaptor plate, thing? We did discuss it at length; but the and the inner ring of the old waterjet ? ts answer was always obvious.” the new one, so it’s an easy process.” It’s

The type S-4 Kongsberg Maritime worth pointing out that swapping out the

Kamewa waterjet boasts a radically old units and replacing them with S-4 improved steering and reversing unit. waterjets was accomplished remarkably

Building upon the proven technology of quickly, in fewer than 10 days.

the SII, it combines an increased work- Following the stringent before-and- ing life expectancy of 10 years with a after tests conducted along Nordlicht’s 15-20% reduction in weight, 20% fewer regular route between Emden and Bor- parts in the waterjet unit and a substan- kum, the results were as decisive as tial decrease in CO2 emissions. Con- everyone had hoped. It was found that veniently, the hydraulic cylinders and the passenger catamaran’s speed had hydraulic hoses are located inboard; a increased from 30 to 32.6 knots while development that has been very grate- still only consuming the same amount fully received by the AG EMS engi- of energy as before. The extra speed is neers, as Claus explains. “Everything a godsend in situations where, for ex- used to be located outside the cockpit, ample, passengers require more transit in the water: you had to carry out repairs time between the train station and the in wintertime on the ice. And then you’d ferry terminal. have the feedback cable getting crushed “Being able to travel more rapidly in the ice, so you’d have no steering if passengers need to make train con- anymore. It was terrible.” nections is a choice we’ve never had

Claus points out that the inboard before,” Claus says. “With the new placement of these components also European passenger rights, you have greatly reduces the risk of oil spills. to make special compensations for any “Even if the hydraulic hoses are broken delays. If it’s half an hour, you have to or damaged, the oil is contained inside give everybody coffee! If it’s an hour, www.marinelink.com 45

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