How to Prepare Your Boat for a Storm
Don’t wait till the hurricane flag flies to ready your boat. Here’s a checklist...
Canals, rivers and waterways are usually better alternatives to marinas, although many of the same problems exist. And each requires a different approach. In canals, try to secure your boat in the center, tying the boat to both sides using the spiderweb technique. Move as far up the canal as possible; the boat will be better protected from storm surge and you reduce the possibility of blocking access to other boats. In wider canals and waterways, secure your boat to anything available: trees, secure pilings and anchors. The more lines and anchors, the better. Again, use lines as long as possible.
One successful technique involves using prebuilt chain and line assemblies. Secure one end of each assembly to a cleat, piling or tree on shore, the other to heavy shackles on one end of the chain. On the boat side of the chain, another shackle and heavy line attach to your boat’s deck cleats. This arrangement makes each line individually adjustable from the deck. Adjust the lines until each length of chain exerts an equal pull on the boat. This prevents the boat from being blown far enough in any direction to come in contact with other boats or objects on shore.
In a blow, the boat is forced to lift the chain. As the wind subsides, the chain settles back down, re-centering the boat. This arrangement also allows for significant amounts of storm surge while keeping the boat centered, because all chain assemblies must be lifted simultaneously. Additional weights (such as lead ingots, barbell weights, and so on) can be added to the catenary of the chain to increase its effectiveness.
Hurricane holes also offer an alternative to crowded marinas. In an ideal hurricane hole sturdy, tall trees and root lattices tend to protect the boat from high winds, in addition to providing excellent terminal points for dock lines and anchors.
Sturdy moorings in protected harbors are also a good alternative to crowded marinas or canals. A boat on a mooring can swing freely to face the wind, reducing windage, and it can’t be slammed into a dock unless the anchor(s) or mooring drags. Several questions arise: What constitutes a sturdy mooring, and will it hold in a hurricane? Other considerations in a harbor are the depth of water and the type of bottom. The proximity of other boats is also a concern.
Considerable testing of the holding power of anchors in all types of bottoms has been conducted by West Marine, BOAT/U.S., numerous anchor manufacturers and Cruising World (April ’96). Most effective were the fluke-type anchors such as Bruce, CQR and Danforth, which bury themselves under load. Mushroom and dead-weight anchors drag with relatively little effort. A mushroom anchor that isn’t sufficiently buried has almost no holding power. During the "Storm Of The Century" in March 1993, which pushed 90-knot winds through my anchorage in Key Largo, Florida, a 40-foot yawl dragged a 10’ x 10’ x 12"-thick slab of concrete 75 yards.
One particularly effective arrangement is to use three burying-type storm anchors with chain rodes, deployed 120 degrees apart and connected together using a heavy swivel. This mooring arrangement was one of the few that held during Hurricane Bob’s onslaught.
In all mooring and anchoring arrangements, remember to increase scope to allow for storm surge -- 10:1 if possible. Use heavy, oversized chain and oversized line in an approximate 50/50 ratio for the bow line. If you are using all-chain rode, use a sturdy snubber approximately 1/10 the length of the rode. The addition of a sentinel (riding weight) to the rode will lower the angle of pull on the anchor and reduce jerking and strain on the boat. Remember that additional scope requires additional swinging room.