Kirkella - named after the village to the west of Hull - will be catching thousands of tonnes of cod off Norway to supply to fish and chip shops across the country.
Built in a Turkish shipyard, its owners Hull-based UK Fisheries, say they have no idea why there’s a sauna - but it should come in handy during 40-day trips when the crew will be working in some of the world’s most inhospitable waters.
Chief executive Jane Sandell said: “It is not normal for trawlers at all, which is why it is causing a bit of a stir. It didn’t look like it had been used when the boat was recently in Hull and it will probably end up as a storeroom.
“But if you are at sea for 40 days some luxuries are probably due to you.”
As well as sophisticated processing and freezing facilities, the ship, which can take up to 24 crew, the majority from East Yorkshire and northern Lincolnshire, also has a hospital on board.
The vessel, skippered by Icelander Sigurbjorn Reimarsson, is currently in Germany picking up technicians to make sure the processing and freezing facilities are working before embarking on a “half” trip.
UK Fisheries, an amalgamation of two Hull trawling firms J.Marr and Boyd Line, which own two other trawlers, are aiming for a 1000 tonnes of product per trip, and may land on the Humber.
Ms Sandell said: “We have been looking at the opportunities for landing into this area.
“It would be absolutely great if we could have the company back here. At the moment our priority is to get the vessel to sea and make sure everything works.”