Weight reduction for Norwegian pilot boats
LOS 118 is the first pilot boat built to a new fuel saving configuration.
When Dockstavarvet delivered LOS 116 to the Norwegian Coastal Administration in May 2008 the boat was received with acclaim at the Fedje Pilot Station outside Bergen. It fulfilled all their requirements regarding seakeeping, operational characteristics and comfort, with a noise level inside reaching only 61 db (A) at full speed.
Before executing an option for four more units of the same type, the customer ordered a review of the design aimed at reducing fuel consumption. Docksta’s design team soon found out that switching to Volvo-Penta D16 engines rated 552kW at 1,900 rpm and driving fixed pitch propellers through Twin Disc Quick Shift gearboxes would reduce weight by 3 tons, with another ton shed on piping and auxiliary systems. Yet another ton was shaved from other equipment, bringing the total weight saving to 5 tons. The preliminary calculations indicated that the same speed could be achieved with a reduction in fuel consumption of 25%.
LOS 118, the first boat of the new configuration, has now been delivered to the Ålesund Pilot Station. The trial results were overwhelming, as the full load speed came out at 29 knots, which has allowed a de-rating of the engines to 480kW at 1,800 rpm while still achieving the contract speed of 25 knots with a very good margin. At this lower Rating 1 the engines are expected to reach 20,000 hours MTBO with low maintenance costs and a fuel consumption of less than 8.5 l/NM. Compared with LOS 116, this is a reduction of over 30 %.
Although a full 5 tons lighter, LOS 118 is fitted with all the latest features of the original specification, including heated decks, boarding platforms and hand rails, a heavy duty fender system and, the Docksta trademark, a resiliently mounted deckhouse which registers a quiet 62 db(A) inside at full speed.
The boat is fitted with a 10 kVA Perkins/Stamford diesel generator for the 3 x 220V AC system which supports domestic loads and a SERVEX aircon/ventilation/defrost system. Each main engine drives a 120A alternator for the 24V DC systems, which have separate banks for start, service, emergency and radio batteries.
The navcomms package is delivered by PRONAV/JRC and includes JMA-5310 and JMA-5210 black-box radars, JHS-182 AIS, NCR-333 Navtex, FF-50 echosounder, CSI Vector PRO GPS compass, Northstar MX500 DGPS, SIMRAD AP-50 autopilot, Maris AEC-6910 chart system and one 19 plus two 17 inch interconnectable flatscreens from Hatteland.
For the pilots an additional 15 inch screen plus a Pilot-Plug provides for situational awarerness before boarding. Two SAILOR RT- 5022 stations are included in the GMDSS A1 package.
In addition to the standard safety equipment, LOS 118 is also fitted with a rescue platform with davit at the transom.
Dockstavarvet is building three more units of this highly specialized pilot craft for the Norwegian Coastal Administration, with delivery December 2009, May and November 2010.
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