The Type 21 VFA “Flipper” standard semi pelagic trawl door is an all-round high aspect trawldoor, being used for many different kinds of fishing setups such as bottom fishing and pelagic fishing.
The type 21-VFA “Flipper” semipelagic trawldoor is built for bottom fishing on soft, sandy grounds and for Pelagic fishing. They are all built with bolted on wearknives and / or flat wide mudshoe. This door is one of the most efficient semipelagic trawl doors in the world.
This semipelagic “Flipper door” has four flaps on the backside of the door. Two on the upper part and two on the lower part, that can be opened manually. The advantage when doing that is, that the surface area is reduced by up to 12,4% and the spreading power can be reduced by up to 17%. At the same time the door’s resistance can be reduced up to 25%. Basically you will have two door sizes in one. Furthermore these flaps can also be used to adjust the pitch and roll.