Breki and Páll Pálsson: big propeller, high-efficiency
The latest additions to the revitalised Icelandic groundfish fleet, fresher trawlers Páll Pálsson and Breki, are expected to dock in Iceland as World Fishing goes to press, as their long delivery trip from China via Singapore, Sri Lanka, Suez and Gibraltar comes to an end.
The two new trawlers replace older vessels built in Japan in the early 1970s, a series of some of the first stern trawlers built for Icelandic companies and which were lengthened and modernised in the 1990s.
The new Páll Pálsson ÍS-102, built for Hraðfrystihúsið-Gunnvör in Hnífsdalur, replaces an older trawler of the same name, while Breki VE-61 is a replacement for Vinnslustöðin (VSV) trawler Jón Vídalin.
The pair measure 51.30 metres overall, with a moulded breadth of 12.80 metres and design draft from the keel of 6.60 metres. The trawlers are identical and were built side-by-side at the Huanghai yard, and they also have the same equipment packages on board. Accommodation is for a crew of up to 18 in three twin and twelve single cabins, and they each have a 615m3 fishroom fitted with a slurry ice system consisting of twin 80-tonne/day icemakers with a 25% ice content.
The new trawlers are designed by Sævar Birgisson of Icelandic naval architect Skipasýn, and a key feature of the sister vessels is the combination of fairly modest engine power with an oversized propeller to provide optimum fishing efficiency. The trade-off is that the draft of the trawlers is greater than usual for vessels of this size, although this does not present any problems in the ports they are expected to operate from.
Páll Pálsson and Breki each have a 1790kW MAN 6L27/38 main engine powering a Reintjes LGF4566 gearbox to turn a MAN VBS1020 three-bladed, 4700mm diameter propeller inside a low drag nozzle designed to provide optimum performance while steaming at 12 knots and towing at 4 knots. The two fishing companies wanted to place the emphasis on energy efficiency and performance, hence the decision to opt for this arrangement.
“The propeller of a fresher trawler uses 90% of the energy produced on board, and 60% of that is required to tow the trawl,” said Sævar Birgisson. ‘So to achieve maximum efficiency, we decided from the outset to focus on the key element, which is the propeller.”
He commented that it is well known that a large, slow-running propeller make more efficient use of energy than smaller propellers running at high speed, so the way forward was seen as maximising propeller size. The limitations lie in how slowly the propeller can be made to turn and the depth of water available.
“The ports these trawlers work from have a working depth of 8 metres, allowing a propeller of 5000 to 5500mm in diameter,” he said. “Most medium speed diesel engines run at 750-1000rpm, and a five metre propeller would ideally turn at 80rpm, so we were looking for a gearbox ratio of 1:10.”
The hull design has distinctive Skipasýn lines, developed for the best possible flow of water back to the propeller and to provide the best possible platform to carry the transducers for fishfinding electronics.
“For a fishing vessel it’s essential to have a clear view of the down into the sea,” Sævar Birgisson said. “So a deep keel with clear lines from the bow and all the way back are what deliver an uncluttered flow around the transducers and to the propeller.”
In addition to the MAN main engines, Páll Pálsson and Breki each have a 1500kVa shaft generator and Caterpillar auxiliaries, with a 440lW C18 and a 150kW C9. Steering gear is from Scan Steering. and each trawler has a high-lift rudder and a 300kW bow thruster.
Páll Pálsson and Breki are designed as twin-rig trawlers, each fitted with three 210kW, 28.30-tonne Ibercisa trawl winches with Naust Marine winch management systems. The decks are laid out with six 55kW, 11-tonne sweepline winches so that three trawls can be kept rigged for use, and a 130kW, 15.60-tonne net drum is located over the deck.
The winch package includes pairs of 55kW gilsons, 45kW codend winches and 30kW outhaul winches, as well as 22kW auxiliary winches and 4kW pullers for the backstrops and gilson backhaulers. Palfinger supplied the PKM550 deck cranes and each trawler also has a 2.50 tonne offloading gantry.
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