If you want to learn to sail with peace-of-mind, you will want to know the steps you need to take if water floods in to your small sailboat. Did you realize that the average small sailboat has ten to twelve holes below the waterline–called “thru-hulls”. Most of these thru-hulls are covered by a valve called a seacock. The seacock has a handle that can be opened to allow seawater in or shut to keep it out.

Marine toilets, sailboat diesel engines, and some galley sinks use sea water to operate. Instruments like knot meters or depth sounders are installed in a thru hull in order to operate. Other thru-hulls allow drainage, like shower sump drains, sink drains, or cockpit scupper drains.

Thru-hulls can become a big problem if not tested often enough. Many folks forget to exercise (open and close) their seacock handles. And this can lead to corrosion, which causes the seacock handle to stick (freeze) in the open position. Each month, conduct this easy three step test on each seacock aboard your boat.

1. Exercise seacocks monthly. Open and close the handle twice.Tap frozen handles with a hammer to free them .
2. Check hoses at the top of the seacock for hardening, cracks, or failure. Replace any hose that shows signs of deterioration. 
3. Inspect hose clamps for rust, corrosion, or cracks. Double clamp each hose to the top tailpiece of each seacock.

Secocks often fail at the hose. The hose cracks or blows off the end of the tailpiece. Then you are unable to close the seacock because the handle has corroded and frozen in the open position. Follow these five easy  steps to make sure you are ready in case of any future flooding emergency.

1. Draw a Hull Outline

Sketch an outline of your boat hull onto a piece of paper. Divide the hull into three separate sections; a “forward” section; “main cabin” section; and “stern” section.

2. Find Your Thru-Hulls

Lash your drawing onto a clipboard. Grab a pencil and flashlight. Start forward and work your way aft. Open up cabinets, lockers, inspection ports, bilge access plates, engine hatch cover, sail and cockpit lockers. Find, plot, and label each seacock on your drawing.

3. Neaten Your Diagram and Post It

Make any final changes to clarify your diagram. For example, you want to be sure that each seacock label can be understood by the greenest crew member. When done, cover your thru-hull diagram with a plastic document protector. Hang it up in the cabin so that it’s visible and ready to use by all of your sailing crew.

4. Arm Your Seacocks

Purchase soft-wood tapered plugs from a marine store. The softer woods swell when wet and will help seal the hole in the top tailpiece of the seacock. Lash a plug to each seacock with a small piece of twine that can be broken with a simple tug. This keeps the plug ready to use in an instant.

Use a small piece of rag over the tapered plug end before you drive the plug into a failed seacock. The rag will fill any voids in the seacock tailpiece and provide friction to keep the plug imbedded in the tailpiece. Keep a hammer or mallet mounted in the cabin. In an emergency, you will want to have one of these tools ready to drive the plug in against the force of gushing water.

5. Set a Flooding Watch

After you’ve made a temporary repair to a seacock, assign a crew member to monitor the repair. The pressure of sea water against a plug can be enormous, and you want to be ready to drive the plug in further if necessary. Set a flooding watch and rotate it once an hour until you can make more permanent repairs.

Learn to sail with safety in mind with a simple seacock diagram and a plan of action. You will be rewarded with the peace-of mind that you are ready to handle any flooding emergency aboard your sailboat–wherever in the world you choose to sail!

Captain John Jamieson shows sailing skippers fast, easy ways to learn to sail like a pro. For a free weekly sailing newsletter plus more sailing tips, articles, and sailing videos, visit skippertips.com