Prepare your boat for rough weather

As a boater, you need to know how to prepare your boat for rough weather well before you see signs of an approaching storm.

Recognize the signs of rough weather

Signs of approaching rough weather include a falling barometer, a swift change in wind speed or direction, waves coming from a new direction, a mass of dark clouds in the west, and fierce lightning. Of course, you’ll also be listening for radio or internet warnings.

Preparing your boat for rough weather

If you’re underway offshore, sail away from the storm, especially the “dangerous quadrant” on the storm’s right front (left front in Southern Hemisphere). To predict the path of a low-pressure storm system, use Buys-Ballot’s law: When you face the wind in the Northern Hemisphere, low pressure is on your right and high pressure is on your left. (This is because wind circulates counterclockwise around a Northern Hemisphere low. The low will be on your left in the Southern Hemisphere, where wind circulates clockwise around a low.)

In the Northern Hemisphere, keep the wind on your starboard side to sail away from the approaching storm except when the wind is south to southwest.

To prepare the boat and crew

Check the fuel. Make sure your tank is full before leaving.
Shorten the sail.
Suit up. Everybody should put on foul-weather gear, life jackets and safety harnesses, which must always be hooked on deck. Rig grab lines in the cockpit and cabin. Take seasickness medication.
Shut and bolt down hatches and posts, and install washboards in the companionway. Take loose gear off the deck. Put protective panels on large windows to keep them from breaking. Below, secure food and other items in lockers. While the boat’s steady, make some hot food and hot water to put in thermoses.

If you’re underway with squalls near shore, follow the steps above. When black clouds appear and sweep your way, expect a squall. After plotting your position, decide if you have time to return to harbor. (To estimate the distance to a squall in miles, time the interval between the flash of lightning and sound of the thunderclap, and divide by 5.) Because squalls are unpredictable, it’s often safest to stay in open water well away from land, shoals and other boats.

If your boat is in harbor, take the following steps to prepare your boat.

Reduce windage. Any exposed area makes the boat sail around its anchor or dock lines, so strip off everything, including all sails, the Bimini top and ventilators. Deflate the dinghy and put it in the cockpit. A hard-bottomed dinghy should be sunk or stored ashore.
At the dock, double or even triple up on dock lines, using plenty of spring lines. Tie leather or cloth chafe protection over lines and fittings. Deploy all your fenders. Tie plastic milk bottles full of water to the bottom of fenders to keep them from riding up.
Set out all your anchors with plenty of scope.
Close all seacocks and other through-hull fittings.