Over the last 18 months Hampidjan has been carrying out a great deal of development work on the company’s Poly Ice trawl doors.
Ventilated slats reduce turbulence significantly
As a trawl door is towed through water, a patch of turbulence forms behind it that pulls constantly against the direction of the tow and this turbulence forms a large part of a trawl door's drag. Hampidjan's aim was to reduce drag, and after some extensive testing, the conclusion was to add these ventilated slats, essentially forcing the turbulence into a constant flow behind the door.
This has improved lift, which the company refers to as the door's squaring power, by as much as 20%, depending on the towing speed.
The doors also have better stability with a more constant relationship between the warps, doors and the trawl while towing, as well as in shooting and hauling and when taking a turn.
Improved bracket
The brackets of the Viking Xstream bottom doors have been redesigned with five plates, each with three holes, to give a total of twelve possible towing positions – something of an improvement on the older design with a single bracket with three towing positions.
The Apollo Xstream pelagic door bracket on the other hand is designed to swivel up or down, forward and backward, to give a total of 20 possible towing positions.
