Every year there are a number of vessels, often small ships, that sink while moored at berth. Mostly this happens due to connections to openings below the water line (e.g. cooling water intakes) freezing up. The inflow of water causes damage to the ship and can incur substantial costs for the owner. In addition there is a risk that leaking oil, above all, will cause environmental damage around the ship. There may be good reason to review such ships and the sensitive points that could cause them to sink. It may also be a good idea to check that any pumps have a good electricity supply and that there is suitable reserve equipment that can start up if something should occur.