How to stop boat from flooding

Beefing up your onboard emergency kit to stop a boat from flooding needn’t be expensive. You probably have most of the supplies and tools at hand.

On recreational boats, add the following items to your onboard emergency kit:

Plugs and patching material. Get wooden wedges and tapered wooden plugs in a variety of sizes to match the boat’s through-hull fittings. You’ll also want an assortment of rubber sheets and gasket material; rags, waterproof putty, and other filler for stuffing in and around patches for a better seal.
Fasteners to hold the patch in place. Make sure you have hose clamps, nylon ties, twine, grease tape, fiberglass tape and duct tape.
Tools. You’ll want screwdrivers, a hacksaw, an adjustable wrench, a pipe wrench, a nut driver, and a hammer. Besides using them to patch a hole, these tools can help you close watertight doors and hatches, shut down machinery that could make a flooded area hazardous, and close off drains and discharges that can siphon water into a boat if it sinks below the waterline.
Dewatering pump. Since bilge pumps aren’t designed to handle large volumes of water from a hole, add a dewatering pump to your kit.

Put these supplies in a clearly marked container kept close at hand. Attach a flashlight to the handle in case an accident happens at night, and make sure everyone on board knows where to find the emergency kit.

Additional precautions

Careful maintenance and regular inspection of pipes, gaskets, valves, and fittings can greatly reduce the chance that mechanical failure will lead to flooding. Likewise, boating education and knowledge of navigation rules and local conditions can minimize collisions, allisions (hitting fixed objects) and hard groundings.

Hold a monthly drill to practice quick action in an emergency. The amount of time a boat operator has to respond to sudden, uncontrolled flooding strongly depends on the size of the hole and its location below the waterline. The lower the hole, the greater the incoming pressure. A 1-inch hole 1 foot below the surface floods at a rate of about 20 gallons a minute. That same small hole 6 feet below the surface floods at nearly two and a half times that rate. Having the proper supplies at hand will help you respond quickly to stop a boat from flooding.

If your boat is taking on water, notify the U.S. Coast Guard and other boaters in the area and make sure everyone is wearing a life jacket. Saving your boat is important, but if you can’t control flooding, saving lives should be your priority. –U.S. Coast Guard