Yes, Amanda. I would expect EVERY underwriter to say "thanks, but no thanks". An underwriter is not required to be rational - he is only required to make what in HIS opinion will be good bets :-)
If I were in your shoes I would begin to look for a reasonable way to dispose of the boat lest it should become a white elephant. I know those are hard words, but do not forget that any "ship breaking costs" are now yours to carry (because you are the owner) and they might well be onerous. If no marina will take you because you cannot get insurance, she'll eventually wind
up on the hook and abandoned somewhere. I've seen many such, and the Canadian government
in fact has a program to do the work
of impounding and breaking boats left on the hook in public waters. The government
comes back on the owner, of course, with a judgement to recover the costs.
Do see if you can get Liability Insurance, only, and a marina berth. Then extricate yourself a graciously as you can.
All the best to you.