The cost of repairing a boat that has been underwater, even briefly, is usually about 40% of its value.

Besides having to pay the deductible, the skipper typically loses the use of the boat for several weeks while it is being repaired. The best defense against a dockside sinking?

Visit your boat. And, at least twice a season, inspect any fittings above or below the waterline that could be letting water into the boat. All too often, skippers rely on bilge pumps to bail them out when they can’t visit their boats. The pump fails and the boat sinks. If you can’t visit your boat often, consider using a buddy system with your friends to watch each other’s boats.

Modern boats sink for a variety of reasons, which is the point of this section. According to the BoatU.S. Marine Insurance claim files, for every boat that sinks underway, four boats sink in their slips. There are two reasons for this discrepancy.

One reason is whenever a boat leaves the dock, someone is aboard, which leaves open the possibility that the leak will be discovered and the problem corrected before it sinks the boat. And, reason # 2, boats tend to spend a majority of their time at the dock.

Boats with motor wells such as this have scuppers that can become clogged with debris. In the case of this boat, the access port had been opened but not resealed. Water trickled into the bilge when it rained, eventually overwhelming the bilge pump.