International Training Course in Trawl Technology

At the North Sea Science Park Flume Tank,
Hirtshals, Denmark

For fishing gear technologists from the fishing industry, research and education

October 28 – November 2, 2012


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The objective of the course is to give the participants an enhanced understanding of trawl performance in practice, both from an engineering, biological and a management point of view. Therefore catch efficiency, fuel consumption, bottom impact, species and size selectivity are all important topics for an optimal use of trawls and keywords for the course.

The participants will study different commercial trawl designs in the Flume Tank and learn how the performance and efficiency of the gear is influenced by changes in net specification, rigging and towing speed. This information will help the participants to select different nets for different fisheries, and assist them in maintaining the trawl.

The participants will be informed of the ongoing research within this field that relates to fish resource management and sustainability e.g. development of species selective gears, measurement and improvement of codend selectivity, as well as environmental impact of fishing gear.


The course is conducted as a residential course at the North Sea Science Park in Hirtshals. It will take the form of both lectures in the classroom on theoretical aspects and practical exercises carried out in the North Sea Science Park flume tank.


October 28 - November 2, 2012. Participants are expected to arrive on Saturday, October 27. They are thereby likely to benefit from cheap air-fares. The Course will start at October 28th at noon. The course ends November Friday 2nd at noon, enabling most participants to return before the weekend.


Demonstration of the design, performance and operation of trawls using scale models in the North Sea Centre flume tank. Introduction to gear research topics like energy savings, computer aided design and simulation of trawls, use of new materials, trawl door design and performance etc. The existing knowledge of fish behaviour in and around the trawl illustrated by means of underwater video recordings taken at sea by cameras mounted on towed underwater vehicles observing trawl performance.

Review of selectivity in fishing gear in general and trawl gear in particular, and possibilities to change the selectivity pattern by altering use and operation, design parameters, construction, etc. Demonstration of various selection devices like grids, sorting panels and windows. Information on gear selectivity characteristics including: influence of cod-end design parameters on fish size selection and utilization of fish behaviour differences to achieve species separation.

Other important aspects of trawl fishing operations: gear legislation (technical regulations measures), requirements for catch quality assurance and hygiene on board fishing vessels, fuel reduction possibilities.


1st day: Trawl engineering performance,
Welcome and introduction,
Introduction to the flume tank,
2nd day: Trawl design
Construction of different trawls, both bottom trawls, pelagic and semi-pelagic,
Design of trawls, and influence of different design parameters,
Flume tank demonstration of trawls for different fisheries.

3rd day: Forces acting on trawls
Trawl reaction to changes in rigging, towing speed, etc.,
The influence on towing resistance of mesh size, netting materials and the orientation of the net bars relative to the flow, T0, T45 and T90,
Overview of the possibilities of reducing gear drag and hence fuel consumption,
Maintenence of trawls.
4th day: Trawl selectivity
Fish behaviour in the catching situation,
Development of selective trawls for different fisheries,
Methods of studying mesh selectivity in cod-ends,
The influence on the size selection of fish of cod-end mesh size,
overall cod-end dimensions, netting materials and cod-end attachments.

5th day: Fish as food and a vital resource,
Morning visit to fish auction in Hirtshals,
Technical regulation measures and sustainable fisheries,
Handling of fish on board,
Influence of the fishing gear design on fish quality,
HACCP (Hazard Analysis and Critical Control Points) and other methods of quality assurance on board,
Evening: Banquet.
6th day: Trawl doors
Demonstration of trawl doors and the influence of design parameters on spreading force and towing resistance characteristics,
Evaluation, ending at noon.

Course organizers

Ulrik Jes Hansen, CATch-Fish, Hjørring, Denmark, and
Mike Montgommerie, SEAFISH, Grimsby, UK
in cooperation with SINTEF Fisheries and Aquaculture, Hirtshals


Everybody who in their professional life are involved with towed fishing gear both from the industry, service industry representatives, and research:
Fishing masters and fleet managers, net and trawl door designers and manufacturers, fisheries biologists and technicians, fisheries college lecturers / instructors, persons who have recently started working as fishing gear technologists / researchers and other persons who want a general introduction to the design and operation of modern commercial fishing trawls.

It is anticipated that the course participants will have a basic knowledge of fisheries and fishing gears.

Minimum number of participants: 12. Maximum number of participants: 20




Course participants will be accommodated at the Motel Nordsøen. Meals will be provided there and at the North Sea Science Park canteen.


€ 2,800 including course fee, meals and accommodation, and transport while in Hirtshals, but exclusive of VAT. Invoice will be forwarded on 22 September 2012.

Please note that the Danish Tax Authorities specify that training in Denmark is charged with VAT. Registered companies in EU will have to pay in their own country, but private persons have to pay Danish VAT of 25%. Registered companies outside the European Union does not have to pay tax in EU.


Please forward registration to CATch-Fish before September 22, 2012. Registration is binding from this date. Payment to CATch-Fish before October 18, 2012.

Click here to fill out the registration form

Registration form

Please note

The organisers has the right to cancel the course in the event that less than 12 participants register for the course.

The Flume Tank