The Faroese company Vonin has been making trawl doors for only eight years, but according to sales manager Olí Gravarbo, its Twister controllable trawl door has been the top seller in Europe for the last three years. “We can barely keep up with the orders,” Gravarbo says.
Vonin introduced the manual control Twister doors in 2020 and brought the semi-automatic Twister doors to market in 2022. “In 2023 we started selling the fully controllable Twister doors, and we are about to upgrade the control system to make it smaller and lighter.”
Gravarbo points out that Vonin’s semi-automatic doors require a wi-fi connection for the captain to adjust their depth and spread.
“That means it has to be out of the water on the gantry,” he says. “The captain can make changes on a computer or tablet. But the fully controllable doors use an acoustic connection with the vessel. There are two hydrophones on the vessel and one on each door.”
Each door has what Gravarbo and the folks at Vonin call a “brain.”
“When we first developed the door we were using components that were available and it was quite large,” he says. “It weighed 50 kilograms. The new brain we have developed weighs only 2 kilos and it can do more.”
The new brain turns the Twister into a smart door. “The doors can talk to each other and keep the spread automatically, even when turning,” says Gravarbo. “More importantly, they keep the depth. The captain sets the desired depth and the doors will control themselves to stay at that depth. That is one of the big benefits of this system.”
In the doors, the brain communicates with a battery-powered motor, a gear and gear shaft that opens and closes the shutters that in turn control the depth and spread, and a pressure compensator. “The semi-automatic door is best for mackerel,” says Gravarbo. “The fully controllable is good for herring and blue whiting, which are our big fisheries here in the Faroes.”
Gravarbo notes that the Twister doors can be upgraded to the second-generation brain. “We just sold an upgrade to a vessel in Norway,” he says.
Located in Fuglafjordur in the Faroe Islands – an autonomous Danish territory situated north of Scotland, about halfway between Iceland and Norway – Vonin has the steelwork on its doors done in Lithuania.
“We have about 400 employees across all our bases of operation and here in the Faroe Islands,” says Gravarbo. “Usually we bring the doors here to install the systems. Sometimes we send our technicians to other countries. We’re sending a team to Morocco next month, for example.”
Vonin’s Twister doors have come on strong in Europe, with skippers like Hjörvar Hjálmarsson, skipper of the Börkur – a 282-foot Icelandic pelagic trawler – vouching for them.
“I am highly satisfied with Twister,” says Hjálmarsson. “We have been in all types of fisheries— capelin, herring, mackerel and blue whiting—since we got the Twister trawl doors. Each fishery has its own challenges, but the Twister trawl doors have not disappointed and have performed very well on every occasion.”
“We have kind of filled the European market,” says Gravarbo. “Now we are bringing the Twister as our icebreaker to the US market. We are also launching the Altura which is designed for fishing close to the bottom, it uses the bottom as a reference point rather than the depth.”
