Seacock Installation

Thru-Hulls And Other Levelingbelow The Water Line Openings

If the boat must be left in the water, all thru-hulls, except those for cockpit drains, have to be protected by closing all seacocks and gate valves. If your boat has thru-hulls below the waterline that can’t be closed, it should be stored ashore for the winter.


Raising and refurbishing a boat that sinks is a daunting job that can keep the boat in the repair yard for many weeks over the spring and summer. When water freezes, it expands and will lift a poorly secured hose off a fitting.


Thru-hulls above the waterline are not required to have seacocks and most don’t. That doesn’t mean that these thru-hulls aren’t vulnerable. Ordinary plastic thru-hulls crack and deteriorate in sunlight, but that won’t sink the boat until the weight of ice and snow in the cockpit forces the thru-hull below the water.


Plastic thru-hulls near the waterline are especially vulnerable and should be replaced with bronze. Plugging exhaust ports will also prevent unwanted guests from finding their way aboard. There have been several claims involving muskrats chewing their way through parts of the exhaust system, sinking the boat.

boat shrink winterizationS

Wherever you end up keeping your boat, if you do not plan to use it for a month or more, you need to winterize it. An increasing number of boats can be stored ashore on dry storage racks. These racks are designed for typical boat hulls, but can’t always be adjusted to support unusual or atypical designs. If you have doubts about the support provided by a rack, consult a marine surveyor or consider an alternative winter location such as a trailer, which has adjustable rollers that can be adapted to different boats.