Dave, I looked up several brands, not just one , and found several listings. Again, not as extensive as the info that you would normally have to pay for, but it may be helpful to some. Hope so.
Liability only
I have used Ski Safe (Part of Geico Insurance Agency, Inc) since 2013 for liability only for my 1988 Albin 34. No increases in premium over this period of time; however, no claims either. Covers salvage and spills. Phone for Ski Safe is 1-800-225-6560