In 1999 a request was made by Jan Bungaard (Thyboron trawldoors) to test their pelagic trawl doors type 8 (11 m²) At that time we applied the American foam doors with reasonable results. A large disadvantage that these type of doors had relatively high drag resulting in towing forces requiring maximum propulsion condition and high fuel consumption, while the maximum trawl spread could not be achieved. The raising oil prices of the last five years were another motive to switch over to fishing doors with lower drag. The results of the first tests were astonishing, especially the high towing speed fishing on sardinella in Mauritania showed very good results with a reduction from 25 to 15-18 ton, leaving opportunities to increase the horizontal spread under equal propulsion conditions.
After several years of successful fishing the type 8 trawldoors the new type 10 (11 m2) became available, with had an adapted shape leading to another hydro-dynamic drag reduction. Personally the switching over to this new type was a logical step. With this type of trawldoors the towing force was further reduced to 12-14 tons with a towing speed increase of 0.3-0.4 miles resulting in a higher horizontal spread, a stable operation, all resulting in an increasing catch efficiency. Also fuel consumption reduced and especially in Mauritinia the improvements were significant.
With these results the type 10 (13 m²) trawldoors were applied in European fisheries on Blue whiting (300-600 m depth) and Greater Argentine (500-900 m depth). This type of doors cpould also be applied in more shallow waters (English Channel).
In Juni 2006 type 15 (11 m²) became available, which were especially succesful in shallow water (15-40 m). Due to the changed shape the stability of these doors in shallow water conditions was further improved, leading to another increase of the horizontal spread with approx. 20 m.
Also in Mauritania these doors were a success with good catch results.
Summary
Fishing the Thyboron trawldoors brings a number of advantages:
higher stability, less drag, optimum performance of fishing gear with less fuel consumption.
Also the application and setting of the trawldoors to the different towing conditions and gear riggings in Europe and Mauritania is easy and time-efficient with low losses of operational time.
We are very satisfied with Thyborøn Trawldoor and also the service is very good!!!!
As skipper fishing with these type of trawldoors results in confidence, which is important issue in relying on the rigging of the trawl, which is expressed in a higher overall efficiency.
Martin van der Meij
skipper Fv Johanna Maria
