My uncle had a previous boat, it was I believe a 1993 Bayliner 26' boat that he had insured through Allstate. I'm not too familiar with insurance terms but he didn't have an "agreed on value", he had I believe a "fair market value" or whatever it's called. Anyway, we have a beach cabin on Whidbey Island with a mooring buoy in front of our cabin, of which one day we had a really bad storm and 60-70 mph winds. The chain on the buoy broke off and the boat drifted down the beach until it beached itself on the sand several miles away. I walked/drove after the boat, anchored it up so it wouldn't go anywhere and later on the next day when the tide was high, we got in the boat and took it back to the dry storage area where he typically stored his boat. I don't know if he ever had the boat inspected after that but a week or two later we put it back out on the buoy and then a couple days later it sunk completely and was a total loss. I can't imagine that being on a flat, smooth sandy beach for a day or two would've put a crack in the hull or damaged it but yeah.
The insurance company jerked him around and said "we'll give you $8k for the boat because we found a similar one in Louisiana", even though he was paying the premium on a $35k policy... and even though the boat they found that was "similar" wasn't even close to being similar. Long story short, he went back and forth with them several times and finally settled I think in the low to mid $20k's, even though he was paying the premiums on a $35k insurance policy and even though he probably had at least $35k into the boat, including purchase price. Allstate basically said take us to court if you're not happy but since then I've become a bit anal on insurance and if it's $500 a year as opposed to $350 for a policy, then I'll pay the extra $150 a year. He also got the boat back from the insurance company as I guess they didn't want to get rid of it, and so we sold it to a local guy I think for $3500 iirc. Frustrating that all insurance companies seem to act differently and some do more than a couple of shady things that make you a bit on the suspicious side when dealing with them. I guess the bottom line is that no one expects to need to file a claim or have a total loss until it actually happens to you, and then you'll very much wish you had a good insurance company with a great policy. Just my 2 cents of course.