Even wooden boats take a very very long time to fully degrade in salt water. If you go around the coast of the UK and look what's sitting in the mud on our sho

Even wooden boats take a very very long time to fully degrade in salt water. If you go around the coast of the UK and look what's sitting in the mud on our shores you'll find a surprisingly large number of ship/boat remains. It tends to be the only the structural parts like ribs and keel that persevere. I guess fibreglass will inevitably last longer, but to put some scale on this the Mary Rose sank in the Solent about 500 years ago, and her wreck was recovered in the early 1980s and put in a museum in Portsmouth dockyard.