After trying out fully controllable trawl doors, it’s not easy to go back to standard gear, said skipper Tor Magne Drønen of Norwegian pelagic vessel Storeknut, which has been using a pair of Vónin’s fully automatic Twister trawl doors since the spring.
“We have been fishing with Twister doors for about five years; first with the manual doors that have to be adjusted to the right settings for a tow before the gear is shot away. Then in May this year, we got new doors and the complete automatic system,” Drønen said.
This has made a significant difference, he believes. Fishing is better, as the automatic doors keep the gear uniformly open throughout a tow, so the trawl is also fishing effectively in a turn.
“With the manual doors, if we took a turn, one door would drop 30 or 40 metres, the gear could collapse and it wouldn’t be fishing,” he said. “Now we can set the doors to the depth that’s required, and they just stay there. This is particularly useful when we’re fishing with the gear high in the water and the headline right on the surface. The trawl stays steady and opens very well. We’ve also seen that we’re using less power and less fuel with these doors. You just adjust the door settings instead of powering up and down all the time.”
Drønen added: “It’s like having more power in the engine room, expect that you don’t have to pay for it. It’s a real gamechanger.”
Switching focus
Storeknut has been fishing with the automatic Twister doors this summer on North Sea herring – but now the focus is on mackerel, and that means a switch to purse seining. “That’s because of the better prices we get for mackerel caught in a purse seine. We’ll be back trawling again with the Twisters doors for North Sea herring, and next year we’ll be using them for fishing blue whiting.”
Storeknut fishes with 1,200- and 1,600-metre trawls for herring and mackerel gear, but there is blue whiting gear on board as well. The 11-square-metre Twister doors adjust seamlessly to all of these trawl rigs and adjustments can be made during a tow, while with the older doors this had to be done manually when there was a change that needed to be made between tows.
“They are very easy to use. We set the depth we need for the trawl doors and they stay there, which is very useful fishing on the surface, and also when we’re working close to the bottom. If you see a mark of fish on the sonar, then the doors can be adjusted to lift or drop the gear, and it responds every quickly without any loss of spread when you have to take a turn,” Drønen said, commenting that they have just once had a minor problem with the setup, and technicians from Vónin had the doors fixed and back to sea the next day.
“That’s very quick service,” he said. “After using these fully controllable doors, it’s very hard to go back to doors without control. So, if there’s a problem, you want it fixed as soon as possible. You try these doors once, and you’re addicted.
