Hurricane experts are predicting an above average hurricane season in the Atlantic. As sailors, there’s nothing we can do to change the outcome of these predictions. But we can be prepared. Planning for the safety of your boat and where it will survive best is a lot like the real estate business: location, location, location. And learning how to moor a sailboat should should come well before the storm.
Where to keep your boat
A secure marina may not be the most hospitable location during a hurricane. There are several important considerations. Does the dockmaster have an established hurricane plan in place? If not, will you be required to evacuate? The physical characteristics of the marina, its surroundings as well as the layout, construction and design of piers and slips all play an important role in the safety of your boat. And despite your best planning efforts, your neighbor may not have been so diligent in his. Loose boats in a marina wreak havoc.
If you plan to keep your boat in a marina, you’ll need to consider your boat and slip design as well as the harbormaster’s configuration. Many marinas designate that alternate slips be vacated when a storm approaches. Others require complete evacuation.
Assess the condition of the marina docks. Are cleats firmly attached? Are the pilings solid? Can the physical condition of the docks, piers, pilings and cleats withstand the tremendous forces involved in hurricane conditions? Many years ago, a vicious low-pressure system carrying storm force winds swept through Sausalito, California, completely severing several finger piers from the main dock. The entire assembly, complete with boats, was swept intact into San Francisco Bay.
If your boat is to remain at a dock, you’ll need to devise a docking plan radically different from your normal arrangement. For most boats, consider pointing the bow toward open water if possible. If not, try to point the bow toward the least protected direction. Unlike boats at anchor or on a mooring, a boat lashed down in a marina cannot turn to face oncoming wind and waves, which may come from totally opposite directions during the course of the storm, radically redirecting the forces on a vessel.
The key to your docking plan should be long lines — the longer the better — to accommodate the predicted storm surge. A good rule of thumb: Storm lines should be at least as long as the boat itself.
Using longer lines will require using other boat owners’ pilings and cleats, and vice versa. Lines may have to be run across marina waterways to facing pilings or to anchors placed in channels. That requires extra planning with other boat owners and marina management. By the time you’ve completed docking your boat, it should resemble a spider in the center of a web.
Your efforts should prevent your boat from moving laterally and at the same time allow it to rise and fall during storm surge. Storm surge may raise your boat completely above adjacent pilings. If your boat isn’t held securely in place, it may be impaled when the surge recedes. Make sure the dock lines cannot slip off the tops of the pilings.
Severe storm surge may completely submerge docks, pilings and cleats. Floating docks present a different set of problems. Storm surge may lift them high enough to slip off their pilings and float away. Many marinas are protected by breakwaters or jetties. They may be totally submerged by storm surge, exposing your normally secure marina to increased fetch, open ocean surge and high waves.
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. 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.
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.
How to secure your boat
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.
Nylon line is well known for its ability to stretch under loads. Under severe loading, however, friction from stretching increases the internal temperature of the line to the point of meltdown. Heat from increased chafe accelerates the wearing process. Normal chafing gear is totally inadequate under hurricane conditions. Chafe protectors must be strong and longer. Remember, you’ll be using longer lines, increasing the percentage of stretch over a given distance. You can make your own protectors using heavy canvas (rubber or neoprene hose may cause trapped heat to melt line). If your chocks will accommodate two layers, add a second layer over the first. Heavy-duty canvas can be purchased through industrial vendors. Check with your local fire department — they sometimes discard used fire hose, which can be fabricated into high-quality, low-wearing chafe protectors.
Secure the chafe protectors to the docking lines. Canvas protectors can be sewn or tied to the line in a similar fashion.
Lines should also be larger in diameter to resist chafe and excessive stretching. Generally you should use 1/2-inch line on boats up to 25 feet, 5/8-inch line for boats 25 to 34 feet and 3/4 to one-inch line for larger boats. Double up on critical lines. Use chafe gear wherever the line comes in contact with anything such as chocks, pulpits, pilings or trees.
Longer, larger and more numerous lines will require larger cleats and chocks. In addition, the extra forces exerted during a hurricane will require stronger attachments of the cleats to the deck. Determine the size of lines you’ll be using and, if necessary, add bigger cleats to accommodate them.
Beef up your dock cleats by adding backing plates if your boat doesn’t already have them — unbacked cleats may pull out of the deck under heavy loads. Use stainless steel plates. Make sure you use the largest size screws that will fit through the mounting holes in the cleats. Use cleats with four mounting holes for added strength. Don’t overload a single cleat — two lines per cleat should be the maximum. If your docking plan calls for more lines than there are cleats available, install additional cleats. Check windlass mounting points as well. The windlass should be mounted solidly with appropriately sized hardware and backing plates.
Boats with keel-stepped masts can also use the mast as a line termination point. Don’t run a line attached to your mast through a deck chock — the extra line length between the mast base and the chock will allow excessive stretch between the two points, increasing chafe at the chock.
Reducing windage
Remove everything to reduce wind resistance: Biminis, antennas, deck-stowed anchors, sails, running rigging, booms, life rings, dinghies and so on. Besides reducing windage, you eliminate the probability of these items being damaged or blown away.
Remove furling headsails. Even when furled, they offer a sizable amount of wind resistance and additional load on the headstay. And despite your best attempts to secure properly the furling line, the ravages of hurricane force winds most likely will unravel your efforts, allowing the sail to unfurl during the storm with disastrous consequences.
Arrange your halyards to reduce flogging and damage, both to the fittings on the halyard and to the objects in their path. One method to eliminate halyard slapping and windage is to tie all halyards off to a common messenger line and run the halyards to the top of the mast, reducing the number of lines exposed to the wind from as many as three or four to only one. Tie the messenger off on a rail.
Preventing water damage
Rain during a hurricane flies in every direction including up. Remove all cowl ventilators and replace with closure plates or tape off the vents using duct tape. Make sure Dorade box and cockpit drains are clear of debris. Close all seacocks except those used for drainage. Put bung plugs in unused thru-hulls and one in the exhaust to prevent water from flooding your engine. Deck drains and pump discharges located near the waterline can back flow when wind and waves put drains underwater.
Use duct tape and precut plywood panels to cover exposed instruments. Examine all hatches, ports, coaming compartments and sea lockers for leaks. Use duct tape to seal them off. Make sure that all papers (magazines, books, catalogs) are high enough in the boat to prevent them from getting wet if the cabin is flooded. Wet paper can turn into a pulpy mush, clogging bilge pumps. Prepare two lists: one listing all items to be removed from the boat prior to moving it to where it will ride out the hurricane and another listing all equipment needed to prepare your boat for the blow.
Electronics are particularly susceptible to water damage; if they can be removed from the boat quickly, add them to the list, along with clothing and other personal effects. Other items that should be removed include: outboard engines, portable fuel tanks, propane tanks, important ship’s papers and personal papers, as well as any other essential personal effects.
What to bring aboard
The list of items to be taken aboard include everything you’ve assembled beforehand to prepare your boat. Many times, the extra “hurricane only” items will be stored ashore — a well-organized list ensures nothing is missed when the hurricane package is taken aboard: extra lines, chafing gear, fenders, anchors, swivels, shackles, duct tape, bung plugs — all the items identified during your planning session. Include a dinghy or some other method for getting ashore after you’ve secured your boat.
Make sure your batteries are fully charged. If needed, take additional batteries aboard to boost available capacity.
Moving your boat before a storm
If you’re planning to move your boat prior to a hurricane, take the boat there on a trial run, noting how long it takes as well as any problems you might encounter under actual emergency conditions. Are there any bridges? Many communities require drawbridges to be “locked down” when a hurricane watch is issued. During Hurricane Andrew, many boat owners were prevented from moving their boats to more protected locations because bridges were locked down.
If you plan on moving a trailerable boat out of the hurricane area, get out early. Many communities prohibit cars with trailers on the road after issuing a hurricane watch. Before the season arrives, inspect your trailer for defects and fix them.
During your test run, make a diagram of how your mooring/docking lines will be arranged. Note any additional equipment you’ll need to secure your boat and add it to the list.
Time is of the essence
Many of the above items will require a substantial amount of time to complete, considerably more than can be accomplished when a hurricane threatens your area. Chandleries will run out of gear quickly when a hurricane looms. After developing your survival plan, purchase and assemble the gear you need to implement it.
Finally, leave early! Waiting to take action until a storm’s imminent arrival is inviting disaster. A hurricane warning is issued when sustained winds exceeding 64 knots are expected within 24 hours. Hurricane-proofing your house or evacuating the area will take precedence over boat safety. Winds may rise quickly. Securing a boat in 35-knot winds is extremely difficult; it’s impossible in 45-knot winds.
A hurricane watch is issued when hurricane conditions pose a threat to a specific coastal area within 36 hours. Drawbridges may be locked down after a watch is issued. You may find your secluded hurricane hole or protected canal inaccessible or already filled with boats.
Start moving as soon as you feel a hurricane watch is probable. Don’t rely on emergency services for assistance. Many harbor and marine patrols remove their vessels from the water or sequester them prior to the onset of storm and hurricane force winds.
After you’ve secured your boat, double-check everything. Turn off all electrical power except the bilge pumps. Test bilge pump switches and pump intakes for debris.
Don’t stay on your boat! Fifty percent of all hurricane-related deaths occur from boat owners trying to secure their boats in deteriorating conditions. Develop a well-thought-out hurricane plan, be prepared to implement it in the shortest possible time and, when completed, leave the boat to its own survival. There is absolutely nothing you can do when hurricane force winds are screaming across the deck.
It’s been decades since William Redfield’s serendipitous discovery of the rotary motion of tropical storms. And the cirrus clouds first observed by Father Benito Viñes still race across a clear, blue, tropical sky ahead of an approaching hurricane. His early warning system has been replaced by weather satellites and advanced computer forecasting systems. Scientists can now predict, with reasonable accuracy, the approximate number of tropical storms and hurricanes that will form in a given season. Watchful electronic eyes constantly beam down updates of their wanderings as they relentlessly gnaw and churn across their expansive ocean feeding grounds.
But the best efforts to predict the path or the intensity of a storm at a given moment still escapes even the best scientists and the most advanced computers. Vilhelm Bjerknes, an eminent meteorologist, accurately describes the physicist’s present attempts at hurricane forecasting: We are in a position of the physicist watching a pot of water coming to a boil. He knows intimately all the processes of energy transfer, molecular kinetics and thermodynamics involved. He can describe them, put them in the form of formulas and tell you a great deal about how much heat will boil how much water. Now ask him to predict precisely where the next bubble will form.
Related Books:
Complete Book Of Anchoring And Mooring, Second edition, by Earl Hinz
A Guide To Preparing Boats And Marinas For Hurricanes, free from BOAT/U.S.
Preparing Your Boat For A Hurricane, Sea Grant College of the State University of Florida
– – –
Ed Eisenberger is an independent marine electronics consultant and the electronics manager for West Marine in Key Largo, Florida. He lives aboard and sails his 41-foot ketch, Wandering Star, from which he keeps a close eye on the weather.
