It was practically love at first sight when a pair of Thyborøn Type 23 Bluestream doors were delivered to Icelandic factory trawler Hrafn Sveinbjarnarson. Now the test set are on board to stay.
‘We’re really impressed with these new doors, and after testing them, both of us are convinced that we need to keep them. After a discussion with the company, the decision was taken to purchase the doors, so they’re staying with us,’ said Valur Pétursson, who skippers freezer trawler Hrafn Sveinbjarnarson opposite Sigurður Jónsson.
These doors are Thyborøn Type 23, a new design of door for demersal trawlers, based on the Bluestream technology used in the company’s pelagic doors.
The same technology has been adapted for this demersal design, making them a semi-pelagic door towed off the bottom, which means they need to be more effective than standard bottom doors as there is no ground contact to provide part of the squaring force. These doors are also lighter to tow, and this makes a significant difference.
The pair that Thorbjörn hf bought were first tested on board Kaldbakur in the autumn with excellent results before they went to Björgvin and then Drangey for evaluation, before it was Hrafn Sveinbjarnarson’s turn.
Square away well
Valur Pétursson said that before the new doors came on board they had been using pelagic doors, a pair of Thyborøn Type 22s with added weights.
‘Those doors worked very well, but to get results we needed to hang a 1600kg weight on the gear. The weights were towed on the bottom and the doors squared very well. There’s no denying that handling the weights in heavy weather could be a challenge. But with the new doors that’s something we don’t have to worry about,’ he said.
‘There’s no problem shooting the trawl and the doors and they work quickly. They’re good in a turn, without the doors losing any efficiency and they hold the square well. As an indication, the door spread is five fathoms more than the bridle length, and we’re happy with that. These doors have a smaller surface area than conventional doors and they’re light to tow, and that includes when we’re coming about.’
Shooting less warp
According to Valur Pétursson, the Type 23 doors are ideal for demersal trawls.
‘The trawls we use are a Hátoppur, otherwise known as a Grindjáni, that Hörður Jónsson makes for us, and a Bacalao trawl. Although we don’t have that much experience yet with these doors, they look promising,’ Valur Pétursson said.
‘These last few weeks we have been fishing in some properly heavy weather and it hasn’t been a problem to get the gear into the water. We can shoot away fast, and that’s because the doors respond quickly and start to square away. This is something we can see clearly from the warp length. We often used to tow with 300 fathoms of warp on a 100 fathom depth, and now we’re using 190 to 240 fathoms, depending on the current.’
He commented that fishing has been good in spite of the long spell of bad weather. He added that it’s particularly satisfying to see the haddock stock gaining strength as there is haddock to be found over a wide area.