Modernisation underway on Bering Sea factory trawler

Alaska Spirit (Photo: O'Hara Corporation)

Work is currently underway to modernise a 204-metre fishing vessel owned by US-based O’Hara Corporation.

Originally completed as an offshore supply vessel in 1974, Alaska Spirit was converted to a factory trawler in the 1990s and then acquired by O’Hara in 2017.

Prior to the refit, the vessel was operated by O’Hara as a head and gut factory trawler in the Bering Sea off Alaska.

Seattle-based naval architecture firm Elliott Bay Design Group (EBDG) has been providing engineering support for the modernisation, which includes replacement of the generator and the hydraulic engines, installation of a new fish factory, conversion of under-utilised aft tanks to stores, rebuilding of the trawl deck, and upgrading of accommodation spaces.

For habitability, O’Hara has refurbished the crew quarters including upgrades to staterooms, laundry, showering and toilet spaces. The company is currently in the planning phase for galley and mess area upgrades, which are expected later this year.

O’Hara has also added silencers to the exhaust lines of all diesel engines, substantially reducing onboard noise pollution for the crew.

Prior to installation, noise on the trawl deck measured approximately 130 dB while the main, generator, and hydraulic engines were operating. Following installation of silencers, the sound level dropped to 85 dB.

For the silencers, EBDG engineered two new stacks and a rebuild of one. The starboard stack aft of the amidships gantry houses the main engine silencer, and the port stack outboard of the gantry houses two silencers for the new generators installed.

The port stack forward of the gantry was also modified to allow installation of a silencer on the new hydraulic engine.

When the vessel was converted for fishing in 1989, the crew relied solely upon burtoning gear; there were no net reels installed and spare nets were carried outboard of the trawl fence. O’Hara has since removed the forward burtoning gear and installed a knuckle boom crane. New trawl winches are being installed this year, and an equipment room is being constructed around the crane pedestal.

Next year, the existing trawl machine located at the forward end of the trawl deck will be removed. In its place will be a pair of net reels and a new gantry.

The base of the gantry and reel foundations are being incorporated into an enlarged changing room for the deck crew. All these modifications have been lofted by EBDG and analysed using finite element analysis (FEA) software.

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