How to Prepare Your Boat for a Storm
Don’t wait till the hurricane flag flies to ready your boat. Here’s a checklist...
Depth and bottom type must also be considered. Normal depths may be altered radically during the approach or departure of a storm. Allow enough scope for storm surge. Conversely, if depths are minimal, your boat may go aground if the wind blows the water out of the harbor. Are there rocks? Your boat may survive the storm only to be torn apart as the storm recedes.
Test the holding ground. Anchor pull tests show that the best holding grounds are hard sand, soft sand, clay, mud, shells and soft mud, roughly in that order. Note that burying-type anchors in an ideal bottom may be impossible to retrieve after a storm.
There is one additional alternative: storing your boat ashore. A study by MIT after Hurricane Gloria found that boats stored ashore were far less likely to sustain damage than those kept in the water. For many boat owners, hauling their boat is the foundation of their hurricane plan.
Boats stored ashore should be well above the anticipated storm surge levels, which is sometimes difficult because most marinas and yards are at or near existing water levels. The same study, however, stated that boats tipped off their jack stands during a storm surge still suffered less damage than their waterborne counterparts.
If you haul your boat, make sure the boat has extra jack stands. Add a layer of plywood between the jack stand pad and the hull to distribute the weight. Chain the stands together. Some smaller sailboats can be laid on their sides to eliminate the risk of being blown or floated off their stands.
No matter where you’ve decided to keep your boat -- in a marina, at a dock, in a canal, hurricane hole or on a mooring, there are several additional points to consider: chafe, cleats and chocks, and windage. Hurricane-force winds exert tremendous strains on boat’s hardware.
Wind force, and the damage it causes, increases exponentially. A doubling of wind speed increases the force on your boat four times. For example, a 20-knot wind exerts a force of 1.3 pounds per square foot; doubling the speed to 40 knots quadruples the pressure to 5.2 pounds per square foot.
Chafe protectors are essential on all lines, wherever you keep your boat. Unprotected lines will chafe and sever within minutes under the rigorous conditions of a hurricane. Boats on a mooring are particularly vulnerable because the boat is usually held in place using only two pennants; the enormous forces generated are concentrated on only two lines.
Depending on your boat, wave surge may increase loading by 1.5 times the values shown. These same forces are transmitted to the mooring; make sure all eye splices have thimbles to reduce wear at the attachment point on the mooring.