PracticalBoater
Skills : Seamanship Techniques

 

Your Starring Role In
Going Aground

By Bob Adriance
Published: October/November 2012

Sometimes, does it feel like you're hitting bottom? Well, in boating, that can be more than a feeling! Here are some proven techniques to free your boat.

No matter if you've been boating 50 years or 50 minutes, whether you own a powerboat or sailboat, whether your boat draws two feet or six, or whether the tide is rising or falling; the first thought that pops into your head the instant your boat unexpectedly touches bottom is always the same: "Oh, &#@%!" If you're lucky, it's just a momentary annoyance the boat bumps and you continue safely on your way. But the boat could also be hard aground, with many hours of struggle ahead before it's freed. If you're going to get off lightly, you'll have to react quickly. A little luck won't hurt either.

Photo of a sailboat run aground being towed

Powerboats: A powerboat skipper's initial reaction should never be to push down on the throttle, either in forward or reverse, and hope for the best. The boat's engine gets its cooling water from somewhere under the boat, and if it sucks up enough mud or sand, the engine could be ruined. This could also damage or tear off the boat's running gear. Shut the engine down until you've ascertained how far the intake is from the bottom. A light displacement boat with a shoal draft can probably be walked to deeper water by the crew if they're good swimmers, wearing shoes if needed, life jackets, and if they're aware of any dangerous current or drop-off.

Check props and rudders (if you can, safely) to make sure they haven't been damaged. On most powerboats, underwater machinery is vulnerable and must be considered as you work to free the boat. Raising an outdrive or outboard slightly will reduce draft. If you decide to use the engine, check the exhaust and temperature gauge periodically to make sure it's pumping water and not sand or mud.

Sailboats: If a boat sailing upwind is to be freed quickly, the helm should be thrown over immediately, away from the shoal, and hopefully wind will heel you off. The crew should move to leeward to reduce draft and then, with a little luck, the wind will nudge the boat back to deeper water. If the boat is sailing downwind, the chances of getting free immediately are slim unless you happen to have bumped a very short shoal. The temptation will be to try and spin the boat 180 degrees so that it's heading back toward open water. This could work, but then again, it might damage the boat's rudder, especially if it's a deep, spade rudder. If the boat remains on the shoal, drop the sails immediately so that it won't be blown further aground.

If you use your engine, make sure it's pumping water. When a boat is heeled, the intake could be out of the water or, equally as serious, sucking up sand, mud, or gunk from the bottom. Check periodically to make sure water is flowing freely from the exhaust, and keep an eye on the temperature gauge.

A Few Considerations

Whether you're freed quickly or not, anytime your boat bumps bottom, check the bilge for rising water. Inspect rudder and shaft stuffing boxes, and on sailboats, the keel bolts. If the boat is leaking badly, man the pumps and call for assistance immediately. Even if the bilge seems dry initially, keep checking periodically to make certain it's still dry.

If wind and current are in danger of putting you further onto a shoal, you'll need to set an anchor to prevent the boat from going harder aground. The anchor can also be used as a kedge to free the boat (see "Techniques"). If a dinghy is available, the anchor should be hung on its stern and the line flaked in the boat so it will pay out smoothly as you row or motor. Whatever way you get the anchor set, you'll want at least 5-to-1 scope.

Next, take soundings of the surrounding bottom to learn what you're up against. Use a lead line (if you have one) or boat hook to measure water depth around the boat and, if possible, get in the dinghy and take additional soundings further away from the boat. While you're probing, find out what type of bottom the boat is stuck in. Boats aground in mud can be rocked from side to side to break the suction (see "Techniques"). Presumably deeper water is astern, and it's probably deeper to one side or the other.

Whenever you go aground, tide is an important consideration. Hopefully, the tide will be low and rising quickly. Consult the tide tables and/or jam your boat hook into the bottom next to the boat and mark the water level with tape. When the water has risen an inch or two above the tape, start working in earnest to free the boat. If it's anywhere near high tide, however, you'll have to work fast. A falling tide can leave a boat high and dry; if you can do so safely, put seat cushions, fenders, or extra life jackets between the hull and rocks to protect it from gouges. Things to check if the boat will be lying at an awkward angle include the battery, fuel vents, any points where water could enter the boat, engine-oil dipstick, and propane bottles (which should be shut off).

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Are Your Backing Plates Up To The Job?

Cleats, windlasses, winches, blocks, and stanchions should all be attached to the deck with substantial backing plates. The best are stainless. If yours are aluminum, check to be sure they’re marine-grade and very thick to minimize distortion from working and from deterioration due to galvanic corrosion where stainless bolts pass through. Thickness depends on the size of your boat and the component secured, but less than 3/8-inch could easily be inadequate. Bow tow rings (bow eyes) in the stem often can’t be backed with sufficient load spreading, and the construction of the boat may not provide enough hull strength for using this as a pull point when aground.

To get pulled off the bottom, you’ll probably need to use a cleat on a hefty windlass and/or heavy-duty bow deck cleats. The more area covered by any backing plates, the better. The wider the stress is spread under the deck, the less likely there is to be a failure. It’s not uncommon in some of today’s boats to have a windlass or cleat pull out, taking a part of the deck with it. Backing plates for windlasses, bow cleats, and other high-stress areas should be as long and wide as possible under the deck. It’s theoretically best to have a stainless backing plate for all stress fittings spreading under the entire bow deck. It also may help to utilize structural support such as bulkheads or ribs by bolting turned-down edges of the plate to these, unless this would weaken that support. Inspect regularly, looking for distortion, signs of corrosion, and flexing of the deck or other structure.

 

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