After years of development, testing, and refinement, auto height is now proving its value onboard working vessels. The system automatically keeps the doors at a set height above the seabed, resulting in minimized bottom contact, reduced fuel consumption, and simplified fishing operations.

A breakthrough for the seabed and for fishermen
“With the auto height feature you can maintain a given distance from the bottom,” explains Henrik Andreassen, Area Sales Manager at Thyboron Trawldoor.

“It eliminates seabed contact at a time when there is strong focus on how fishing gear interacts with the marine environment. That makes this feature groundbreaking for the seabed.”

The benefits go further than sustainability. Crews are finding operations easier, since the doors no longer need to be lifted completely out of the water during turns. This saves time and increases efficiency. By keeping the doors clear of the seabed, wear and tear is also reduced, which extends the life of the equipment.

The auto height edge is now available with Type 32 and Type 42 Bluestream controllable doors, where savings of 5–25% in fuel consumption have already been documented, depending on what equipment the new doors replace. Lower fuel use means less CO₂ per kilo of fish caught – and a stronger bottom line for skippers. The feature’s also proven invaluable on uneven seabeds, where precise clearance is critical.

As an example, Henrik Andreassen points to fishing on uneven ground: “On rough terrain, like around a seamount, the auto height edge really proves its value. You can fish with confidence, knowing the doors are maintaining the exact clearance from the seabed that you have set,” he says.

Proven at sea
The auto height feature has already demonstrated strong results at sea. Skipper Ola Hansson, from the F/V KRISTIN NC336, has tested the system in several fisheries and describes the difference it makes:

”In daytime sprat fishing in the North Sea, we use the auto height function set to 1 meter, and it works excellently. We can turn and steer in spots without one of the doors lifting off the bottom or simply falling. In the evening, we can follow the sprat when it rises higher off the seabed by increasing the auto height as needed,” says Ola Hansson and continues:

”We no longer need to adjust any settings on the upper or lower back straps on the doors, which provides a safer working environment. The auto height feature has given us an additional way to increase control of the doors, and thereby the trawl.”

Ola Hansson is very happy with the new options that make fishing a lot more convenient and easier.

“We can see that we have better control over the doors, and on the trawl sonar we can observe how just a few meters’ increase in auto height makes the trawl open more or less, and how the trawl tips work harder or softer against the bottom. This ensures the desired bottom contact with the entire trawl can be achieved – or avoided – as needed,” he says.

Developed in-house in Thyboron
The auto height feature is the result of Thyboron Trawldoor’s in-house development department, where naval architecture, hydrodynamics, and practical fishing knowledge are combined. The team uses CFD flow simulations, extensive flume tank testing in Hirtshals, and multiple full-scale trials before a design reaches the market. The Type 42, for instance, went through 14 model iterations before the final version was built.

By keeping design and hydraulics in-house – and reinvesting a significant part of revenue into R&D – Thyboron Trawldoor ensures it can stay ahead of the curve and deliver durable products that fishermen can rely on for years.

The future of fishing gear
Controllable doors are quickly becoming standard in modern fisheries. By successfully delivering the auto height feature to fishermen, Thyboron Trawldoor once again demonstrates its role as a technology leader, combining performance with sustainability.

“As quotas tighten and costs rise, fishermen need to catch efficiently, sustainably, and profitably,” concludes Henrik Andreassen. “Auto height is not just a feature – it’s the future of trawl doors.”

About Thyboron Trawldoor
Thyboron Trawldoor is a global leader in advanced trawl door technology, supplying vessels in more than 50 countries. With a strong focus on innovation, sustainability, and close collaboration with fishermen, the company develops and manufactures a full range of doors – from conventional models to the world’s most advanced controllable solutions.