I am not an attorney and not an insurance rep so take my advice accordingly.
1. Most general umbrella policies require one to carry some level of liability insurance
regardless of whether it is a homeowners, auto, boat, etc BEFORE the umbrella
kicks in. The umbrella policy underwriter will want to know these things as it
determines their level of risk and of course the cost of the umbrella policy for you.
2. Most marinas will require you to have a certain amount of liability insurance on
a dedicated boat policy. Furthermore, it is very common for marinas to require
that you list them as an "additional insured" on the boat policy.
3. As others have mentioned, if your boat has a major oil leak or fuel leak (whether it
sinks or not), it will cost a fortune to comply with the USCG spill regulations. I cant
imagine the cost of a service company to place oil booms to contain a spill, suck it up
and dispose of it properly. Not to mention the liability for oil damage & stains to your
neighbors in surrounding slips.
4. If the boat sinks, you are going to have to pay divers to place inflatable bags, patch
a hole temporarily, and pump out the boat to refloat it or in the case of some
weather event, a barge and crane may be necessary to extract it. If the boat has to
be salvaged and destroyed, lord only knows what the cost would be.
5. If you have to have someone work on your boat and that person is injured, there
are differing laws as to how the liability is determined as compared to someone
working on your house. Jones Act and Longhsoremen's & harbor workers
compensation can sometimes become a factor that a smart attorney can pursue.
6. Boats in the 30' class become classified as "yachts" and for insurance purporses
they are treated as a different animal.
I wouldn't even contemplate not getting a "yacht" policy from a reputable insurance co., because of all of the potential liabilities. The cost of the policy on a fresh water lake that has no hurricane exposure should be minimal. Whether you insurance it for an agreed upon replacement value is optional. Also, I think the survey cost is a necessity on a 30 foot boat. I have been around boats for over 30 years; however, I don't know as much as good surveyor about potential problems areas; in my opinion the survey is money well spent. It would be really an embarrassing and costly dilemma to find out after you purchase the boat that an insurance company requires a survey and you find out there are major problems with the boat after the purchase, on
a "post purchase" insurance survey. It is a traumatic experience to lose a boat and have it totaled. My previous boat was totaled in Hurricane Katrina, 10 years ago. The insurance company handled EVERYTHING including extracting the boat, hauling it away, and salvaging it. Of course I had it also insured for an agreed upon value. The only thing that was required of me was to sign the title of ownership to the insurance Co. and have it notarized. I got a check in the mail about one month later. I couldn't imagine all of the headaches and expense of dealing with that myself. Believe me, you have my sympathy--boat ownership is an expensive hobby!