How do I winterise my boat?

Most craft will have fresh water on board either in water tanks, engines or toilets. To prevent frost damage all water systems need to be drained off or inhibited. Outboard motors self drain so are safe, inboard engines whether directly or indirectly cooled require attention. All domestic water systems particularly water heaters require draining off. Sea toilets have to be winterised. Craft that are ashore are vulnerable to frost damage as there is no surrounding water to partially insulate the craft.