Fishing Trawler

Overview

A fishing trawler catches fish by dragging a large cone-shaped net through the water and storing the catch in a chilled hold until landing. It is a working platform organised around that cycle: shoot the net, tow it for hours, haul it, empty it, and stow the fish cold. The hull is built heavy in steel because the boat works year-round in open water and takes the strain of the gear it drags behind it.

The vessel rides a welded steel Steel Hull & Superstructure with a deckhouse forward and an open working deck aft. Below it, the Marine Diesel Engine turns the Gearbox, Shaft & Propeller propeller, and the boat is steered by Steering Gear gear. The fishing is done by the Trawl Gear across the stern, and the catch goes into the refrigerated Fish Hold & Refrigeration. The skipper runs the boat and finds fish from the Wheelhouse, with power supplied by the Diesel Generator and the Electrical System switchboard.

How it works

The main diesel develops slow, high-torque rotation through its reduction gearbox so the large propeller can produce the steady pull needed to tow a net against the drag of the water. At the stern, the Trawl Gear winch pays out two warps that lead to a pair of otter boards; angled like underwater kites, the boards sheer outward and hold the net's mouth open while it is towed along the seabed or in midwater. The net drum then reels the gear back aboard over the gantry when the tow is done.

Finding the fish is the wheelhouse's job: the Wheelhouse sonar sweeps the water ahead and below for schools, while radar and a chartplotter keep the boat safe and on its grounds. Once aboard, the catch drops into the insulated Fish Hold & Refrigeration, where a motor-driven refrigeration compressor and cooling coils hold it near freezing so it stays in good condition until landing. The diesel Diesel Generator supplies the heavy intermittent loads of the winches and the constant draw of the refrigeration plant.