1. A large percentage of claims are fraud. The insurance company is not out to get you, but to protect the premiums of the rest of us.
2. Maintenance is the single biggest cause of sinking at the dock. It is not a covered loss as the insurance company will not cover a loss due to inadequate maintenance.
If you have any survey from the past, especially one given to the insurance company at any time, all items should be fixed, repaired, or mitigated in some way and keep proof of that. A maintenance log, receipts and pictures will go a long way to saving your butt when the time comes.
If you have any glaring issues like hose clamps, hoses, etc. They will cost you a fortune if they are the cause of sinking.
As stupid as it sounds, we use a pilots checklist on our boat.
Why is it not stupid? Just about any dock sinking can be attributed to a maintenance issue. If you walk into court with documents, receipts and logs showing you have maintained the boat as prudently as possible, there is not a judge or jury who would side with the insurance company unless the act was proven deliberate or a result of workmanship on a recently completed job by a yard or other hired professional.
3. This leads me to the "out" many yards and professionals are using in their work-orders. They ask you to sign away your right to allow the insurance company to subrogate on your behalf. This means if they cause the boat to sink, the insurance company would pay your claim, then go after the yard that was found to be the cause. If you sign away that right, your policy is null and void and you have to fight the yard yourself and their liability can be written as such they that they will replace the defective part only, and pay for the haul to do so. Leaving the rest of the boat ruined and possible hefty environmental and towing/salvage bill.
4. Document EVERYTHING. Times you called, who you called, who you talked to, what you did, etc. If you are ever asked a question in court and state that you kept notes on everything and if you may refer to them, then give exact details, you will impress a judge. Trust me, they will come in with those records of when you called, who you talked to, etc.
5. If you have good records, can document everything, the boat was in great shape, etc. Talk to a good attorney in a consult and have him at the ready if it starts to go south.
6. Same as #5 on shape and documentation, make sure you stop at nothing to find the reason the boat sank, if they can't find a reason, get the police involved with a police report if you think it may have been human caused, or pay the yard to keep the boat in a slip next to the yard until the problem is found if you think it was caused otherwise. Be more concerned with finding out why then who is going to pay or get paid.
A lot of people blast the insurance companies for failure to pay on the loss when they don't maintain their boats at all and then complain to the world about it. If there is a years worth of growth on the bottom and the boat looks like it was last cleaned when Carter was president, don't even bother putting a claim in.
It breaks my heart to hear the many stories about a boat sinking after a yard or mechanic made a mistake. Make sure not to sign your rights away and let the insurance company fight the yard for you.