A hurricane watch is posted when hurricane conditions pose a threat to a specified coastal area, usually within 36 hours. Some hurricane observers believe waiting for a watch to be posted also may be too late to head for the marina or to move the boat to a safer location.
A hurricane warning advisory is posted when sustained winds of 74 mph or higher are expected within 24 hours or less--too late, in most situations, to head for the boat. Securing the house, gathering emergency provisions, and evacuating the family will need attention at this point.
The best advice is to prepare or move your boat when a hurricane is a substantial possibility, even before a hurricane watch is issued. If you wait longer, and your plan includes relocating the boat, bridges may be locked down and the hurricane hole you chose may be inaccessible. Or, if you planned to have your boat weather the storm ashore, you may find the marina is too busy to haul your boat.
One of the first steps when preparing your boat for a storm is to take off all loose gear that will create windage: canvas covers, bimini tops, spray dodgers, outriggers, antennas, anchors, running rigging, booms, life rings, dinghies, portable davits, etc. Sails also create a lot of windage, especially when they come unfurled, and should never be left on deck in a storm. If there's time, windage can be greatly reduced on a sailboat by unstepping the boom and mast.
Remove cowl ventilators and seal the openings. Use duct tape to cover instrument gauges. Duct tape should also be used around hatches, ports, lockers, etc. to prevent water damage below. Close all but the cockpit drain seacocks and bang a plug into the engine's exhaust ports. If the boat does take on water, it will sit lower, and water could back-up into the cylinders. (Remember to remove the plug before starting the engine when the storm has passed.)
Boats stored ashore are far more likely to be saved than boats stored in the water. There are some types of boats that must be pulled if they are to have any chance of surviving. Smaller, open boats and high performance powerboats with low freeboard will almost always be overcome by waves, spray, and rain. Fortunately, most of these boats can be placed on trailers and transported inland. Boats ashore should be stored well above the anticipated storm surge, but even when boats are tipped off jackstands and cradles by rising water, the damage they sustain in a storm tends to be less severe than the damage to boats left in the water. Windage is also a consideration. If nothing else, reduce windage as much as possible and make sure your boat has extra jackstands, at least three or four on each side for boats under 30’ and five or six for larger boats. The jackstands must be supported by plywood and chained together. Smaller sailboats can be laid on their sides. High-rise storage racks are vulnerable in a storm’s high winds. Several have been completely destroyed in recent hurricanes. If possible, boats on storage racks should be placed on trailers and taken home.
A trailer is a ticket to take your boat inland, to a more sheltered location away from the tidal surge. But your boat won't get far on a neglected trailer that has two flat tires and rusted wheel bearings. Inspect your trailer regularly to make sure it will be operable when it's needed.
If you take your boat home, you may want to leave it, and not your car, in the garage. A boat is lighter and more vulnerable to high winds than a car. If this isn't practical, put the boat and trailer where they will get the best protection from wind, falling branches, etc.
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. (Rain will add a lot more water later.) This has the added advantage of giving you emergency water (non-drinking) if the main water supply gets knocked out by the hurricane. Place wood blocks between the trailer's frame and springs to support the added weight. On a boat with a stern drive, remove the drain plug so that the engine won't be damaged by flooding.
Secure the trailer to trees or with anchors or augers. Strip all loose gear, bimini tops, canvas covers, electronics, etc. and then lash the boat to the trailer.
Any boat in the water should be secured in a snug harbor (don’t even think about riding out the storm at sea unless you’re the skipper of an aircraft carrier). The trick is deciding which harbors will be still be snug if a hurricane comes ashore and which will be vulnerable. Storm surge—high water—is a major consideration. A storm surge of 10’ or more is common in a hurricane, so a seawall or sandy spit that normally protects a harbor may not offer any protection in a hurricane. Crowded, rock strewn harbors are picturesque, but they may not be the best place to keep your boat in a storm. Rocks are hard on boats, should yours break loose, and in a crowded harbor the chance of another boat breaking loose and banging into your boat is that much greater. Finally, what is the bottom of the harbor like? If you plan to anchor, check your charts to see how much water your boat will be anchored in. The best anchoring is usually in sand, followed by clay, hard mud, shells, broken shells, and soft mud. Also, water can sometimes be blown out of the harbor, leaving boats stranded briefly. If this happens, your boat would rather settle onto anything but rocks.
As many as 50% of the boats damaged during Hurricane Fran could have been saved by using better docklines: lines that were longer, larger, arranged better, and/or protected against chafing. If you decide to leave your boat at a dock, you'll need to devise a docking plan that is liable to be far different than your normal docking arrangement. By the time preparations are completed, your boat should resemble a spider suspended in the center of a large web. This web will allow the boat to rise on the surge, be bounced around by the storm, and still remain in position.
Take a look at your boat slip and its relation to the rest of the harbor. For most boats you'll want to arrange the bow toward open water or, lacking that, toward the least protected direction. This reduces windage. Next, look for trees, pilings, and dock cleats-anything sturdy-that could be used for securing docklines. With most docking arrangements, lines will have to be fairly taut if the boat is going to be kept away from pilings. The key to your docking arrangement is to use long lines, the longer the better, to accommodate the surge. (A good rule of thumb: storm docklines should be at least as long as the boat itself.) You will probably want to use other boat owners' pilings (and vice versa), which calls for a great deal of planning and cooperation with slip neighbors and marina management.
Lines should also be a larger diameter to resist chafe and excessive stretching. On most boats you should use 3/8 inch line for boats up to 20 feet, 1/2 inch line for boats 20-34 feet, and 5/8-3/4 inch lines for larger boats. Chafe protectors must be on any portion of the line that could be chafed by chocks, pulpits, pilings, etc. To secure lines to hard-to-reach outer pilings, put the eye on the piling so that lines can be adjusted from the boat. For other lines, put the eye on the boat to allow for final adjustment from the dock.
Remember to also remove all loose items on deck including bimini tops, plastic side enclosures, sails and dinghies. Store them on land. Store small, loose items below deck, including antennas. Secure all hatches and doors, and tape all windows from the inside. Disconnect electric, water and other connections from dock. Shut off fuel lines at the tank and close through hull fittings. Remove all electronics and valuables to prevent destruction or theft. When you are through: Help your neighbors. All it takes is one boat incorrectly tied up to damage many in a marina or Harbor.
Mooring in a sheltered location can also be a good alternative to exposed harbors and/or crowded marinas. A boat on a mooring can swing to face the wind, which reduces windage, and it can't be slammed into a dock unless the anchor or mooring drags.
The first question, then, is will your mooring hold? As a result of numerous moorings being dragged during recent hurricanes and northeasters, a search has been underway for a more secure mooring anchor. A recent BoatU.S. test using a large tug and several types of moorings found that the moorings that are the least likely to be dragged are the "embedment" type anchors-a helical and an expanding fluke anchor- which are deliberately screwed or driven into the harbor bottom. Traditional moorings-mushroom anchor and dead-weight blocks- were far more likely to be dragged with relatively little effort. A mushroom anchor that isn't sufficiently buried has very little holding power. The holding power of a mushroom or deadweight anchor can be increased by extending the pennant's scope, but you also have to consider the proximity of other boats. Embedment anchors do not rely on scope to increase their holding power, but scope must be sufficient to allow for tidal surge.
If you have doubts about your mooring, the chances of its dragging can be reduced significantly by using one or two additional storm anchors to enhance its holding power and to decrease the room your boat will need to swing. An arrangement that uses two anchors (or a mooring and an anchor) set 45° apart has been used successfully to moor boats in storms. Chafe gear is essential on any line, but it is especially important on a mooring line. Recent storms have given dramatic evidence that a boat on a mooring is especially vulnerable to chafing through its pennants. Unlike a boat at a dock, which is usually sheltered and is secured with multiple lines, a boat on a mooring is typically in a more exposed location and secured with only two pennants, which are under enormous loads and will chafe through quickly if they aren't protected.
Whenever canals, rivers, or waterways are available, they serve as shelters-hurricane holes-and offer an attractive alternative to crowded harbors and marinas. Your mooring arrangement will depend on the nature of the hurricane hole.
In a narrow residential canal, a boat should be secured in the center with several sturdy lines ashore (the "spider web ") to both sides of the canal. This technique was common to most of the boats in canals that survived Hurricane Andrew. Conversely, boats that were left at docks without the benefit of lines to both sides of the canal didn't fare any better during Andrew than boats at marina docks. The boat should be facing the canal's entrance and be as far back from open water as possible. Besides sheltering the boat, being away from the entrance should help with another consideration, which is the need to maintain a navigable waterway.
Securing boats in canals with private homes is possible only if you make arrangements with the homeowners whose trees and pilings you will be using to secure your boat. This can be difficult if your boat isn't normally moored in the canal. If your boat is already in the canal, getting other homeowners involved in planning for a hurricane increases the chances that your boat (and theirs) will survive. This is important. All it takes to wreak havoc in a narrow canal is one or two neglected boats coming loose.
In wider canals and waterways, boats should be secured using a combination of anchors and lines tied to trees ashore. The more lines and anchors the better. Try to find a spot that is well away from open water and that has tall banks, sturdy trees, and few homes. Moor your boat away from the main channel. Other considerations: a hurricane hole that ordinarily takes an hour to reach may take two hours to reach when winds and seas are building; bridges may not open as frequently once a hurricane warning has been posted; or the bridges may be locked down to evacuate cars. (This was the case on the Miami River before Hurricane Andrew.) Plan on moving your boat early.
One of the most dangerous mistakes a skipper can make is to stay aboard his or her boat during a hurricane. Several accounts given in claim files indicate that there is little, if anything, a skipper can do to save a boat when winds are blowing 100 mph, tides are surging, and visibility is only a few feet. A boat is no place to be during a hurricane. The unpredictability of secondary weather events such as tornadoes coupled with violent wind and wave action in proximity to other boats and docks is potentially deadly.
When a hurricane is approaching, you should certainly do everything you can to protect your boat: secure extra lines, set out anchors, add chafe protection, strip the boat above and below decks, etc. Do whatever you think it takes, then head inland. Your boat can be replaced; you can’t.
Chafe protectors are essential on all lines: at a dock, at a mooring, or at anchor. Nylon stretches and absorbs shock, which is good, but this stretching under tremendous loads also works the line against chocks and other contact points. On moorings or at anchor, the line stretched over the edge of the rail can create sufficient heat to melt the line internally. Polyester (Dacron) has much less stretch, but is more chafe resistant than nylon. By using a polyester line from the cleat through the chock and then joining it with a nylon line (use two eyes) to the piling or mooring, you can get the best of both types of line-the chafe resistance of polyester and the stretch of nylon.
Any line must be protected in a storm. For a super system, if your chocks are large enough, fit a second, larger diameter hose around another hose that fits snugly to the line. Drill holes in both hoses, and use cord to tie them securely to the line. In a pinch you can use a single hose.
If you need chafe protection quickly, use duct tape (a lot) to secure several layers of heavy canvas to the lines. This won't be as rugged as hose, but it is certainly better than leaving the line unprotected.
Many boats have cleats and chocks that are woefully inadequate. This problem becomes critical when more and larger diameter storm lines are used during a storm. If necessary, add more and larger cleats and chocks now; they'll make securing the boat easier all year. Asses the ability of cleats to carry heavy loads. This means making sure all are backed properly with stainless steel or aluminum plates. Marine plywood is OK if it's healthy-free of rot and delamination. On sailboats, winches (if backed properly) and even keel stepped masts can also be used to secure lines at a dock. (NOTE: Anchor lines should NOT be secured to the mast, as it creates that much more stretch on the line at the chock, which further increases the chances of chafe failure.)
Don't put too many eggs in one basket by leading numerous lines to a single cleat, even if it is backed properly. Two lines per cleat is probably the maximum. Also, a cleat is not reliable when lines are led perpendicular to the base and the cleat can be wrenched out by the tremendous loads (see diagram). Two-hole cleats are more vulnerable than four-hole cleats.Source: Boat U.S. Hurricane Resource Center