Whether you store your boat in your backyard or have it docked on the water, there are some simple things you should do before a hurricane hits:
Remove small boats from the water and move them to a secure location; the more inland the better.
Be sure your trailer and boat are secured above the likely flood areas.
Remove all loose items on board.
Tie the boat securely to the trailer or tie it to trees. It doesn't hurt to throw out the anchor.
Let some air out of the trailer tires and block the wheels.
You can increase the weight of lighter outboard boats by leaving the drain plug in and using a garden hose to add water. This has the added advantage of giving you emergency water (non-drinking) if the hurricane knocks out the main water supply.
Place wood blocks between the trailer's frame and axle to support the added weight.
In some cases you may want to plug the engine's exhaust outlet.
If possible, boats on stor age racks should be placed on trailers and taken home.
If your boat is too large to take out of the water, move it to a safe haven well before the storm approaches. You should know where safe havens are in the area where you boat.
Double up and secure mooring lines.
By the time preparations are completed, your boat should resemble a spider suspended in the center of a large web.
Secure all hatches and portals and cover windscreens.
Take down mast whenever possible.
It's best NOT to leave your boat on davits. If you must, be sure to remove the drain plug to avoid excess water weight.
A study by MIT after hurricane Gloria found that boats stored ashore were more likely to be saved than boats that were kept in the water. Members of the BoatU.S. Catastrophe team estimated that as many as 50% of the boats damaged during Hurricane Fran could have been saved by using better dock lines.