Not uncommon, even today for merchant seamen to take their wives and small children with them on long voyages, much more common in earlier times. I was brought up in Boston near the docks, and in the late 1940s and 1950s the small coastal ships using the docks, generally from Netherlands, Germany and Denmark, but with a few rarer visitors from Eastern Europe and Russia thrown in, along with some British often had women on board. Some of the Eastern Europeans were often officers.
By that time there was no trawling out of Boston, the Boston Deep Sea Fishing co. had moved to Fleetwood in the 1920s, so there were only the local inshore boats left. None of these stayed out overnight really, sometimes though due to tidal conditions.
Scandinavian names in Grimsby are quite common, when compiling payroll for Grimsby railway staff in the 1960s I was struck by the numbers of people whose names ended in ---sen and ----mann, so again this does not surprise. Regarding spelling, it is always well to remember that there was no standard spelling before the late 18th century, and then due to lack of education it caught on rather slowly. Like a registrar recording a birth etc. a painter naming a fishing boat would record what he heard, and paint that on the side of the boat. There are similar records of eccentrically spelt locomotive names from the railway engine builders. Again the same cause.
