Heavy Weather Moorings

Hurricane Season is Coming, Are You Ready?

26th July 2001.
By Roger Marshall

The Helix Anchor

The Helix Anchor

According to various experts the East Coast will be hit by 12 to 14 hurricanes this year. Since the hurricane season is between June and October, it is highly likely that your boat will be in the water when a hurricane hits. To protect your boat when it is on its mooring in a harbor you need to have the best mooring possible. You also need good chafe protection, a strong pennant, and good mooring tackle.

There are a number of things you must attend to when the boat is sitting on its mooring during a storm. First you need to cut down on as much windage as possible. That means removing the roller furling headsail, the mainsail, any dodgers, biminis, leecloths, and awnings onboard. You should also take your dinghy ashore and put it in your garage or other safe place. If you can’t get your boat ashore, make sure you take electronics, sails and any other gear ashore before the storm hits.

The best preventative measure

Long before a hurricane hits, make sure that you are on your yard’s list to have your boat hauled and taken ashore. According to an MIT survey made after hurricane Gloria in August 1991, no boats that were lifted out and stored ashore above the tidal surge line suffered damage. So the safest course of action is to get your boat hauled out.

Around here the local yards start hauling boats as soon as a hurricane watch is forecast. They literally work around the clock to get as many boats out as possible. Jim Archibald, Manager of the Jamestown Boatyard, said “We haul until we have finished our list. Then we check every boat on one of our moorings and make sure it is secured properly. We also call owners and make sure they know what we are doing with their boat.”

Facing a Storm on a Mooring

If your boat is on a mooring and you cannot move it, check your mooring or confirm that the yard checked it in the spring. If you have any worries about your mooring, before a storm hits, hire a diver to go down the mooring line and make sure that there are no corroded spots (corrosion weakens chain and a storm surge may cause it to break). Check the shackles to ensure they are tight, and check that the anchors or mooring blocks are firmly embedded in the sea bottom. If you find corrosion or have any doubts about your chain, replace it or move to a new mooring.

Check your mooring pennants for chafe. If a pennant shows signs of chafe, replace it. In the past, I recommended that you put heavy duty plastic tubing around the pennant to protect it from chafe, but an MIT study found that nylon lines actually heat up internally from the friction of stretching and shrinking. Dry nylon suffers the worst. Wet nylon is much less likely to be affected by heat because water acts as a lubricant. By putting a plastic cover over your nylon line you may be keeping it dry, containing the heat, and helping to destroy the line. I now recommend that a mooring line be made of braided polyester line between the boat and the mooring buoy, with nylon below the mooring buoy. Some experts suggest that mooring lines be fitted with a Hazelett rode and be backed up with a chafe protected polyester line running from the boat to the mooring buoy. Never having used a Hazlett mooring rode, I have yet to verify first hand if they are effective.

In my opinion, on an ideal mooring, a nylon line should run from the buoy to the chain, with 12 or 15 feet of chain fastened to a helix mooring. Above the mooring buoy, the line should be braided polyester. With this system the scope of your mooring rode can be reduced cutting down on the amount your boat swings, but the anchor will not be lifted off the seabed.

Check, too, the cleats on the bow of your boat. They should be strongly fastened to guard against being torn out of the deck. If you have any doubts about the strength of your mooring cleats, take a line from the mooring pennant around the mast or windlass. Based on all the information I have seen lately, I would also suggest that builders strongly mount cleats where they do not have to pass through chocks. This will reduce chafe on the line when the boat is tied up at a dock, when it is moored, and when the boat is lying to a sea anchor.

When a storm approaches, double up your mooring lines or put a bridle around the bow of your boat to take the strain. Any line leaving your boat should have some form of chafe protection on it. The best chafe protection is a 3 to 4 feet length of fender tubing available from Davis Instruments or Perimeter Industries. It should be placed over your mooring line and secured in place by sewing or with a lashing. With this lashing, the chafe protection cannot slide down the anchor line. Check, too, that there are no sharp edges around the bow of your boat that might abrade the mooring line enough to break it. Quite often, the stemhead fitting has a sharp corner, or there is a sharp edge at the corner of the deck or on the bow chock. These edges will chew through an anchor line in a remarkably short time.

You should take an additional line from the bow to the mooring chain under the mooring buoy. Often when a mooring line snaps it is the swivel at the buoy that breaks. An additional line fed directly through the chain can give your boat an extra factor of safety. Also in a very severe storm, you might lay out your own anchor line to relieve the strain on the mooring line. Remember, though, that if the eye of the storm passes over you the wind direction will change, making your boat swing around and causing your anchor line to tangle in the mooring line. This might be enough to cause your mooring line to lift or part.

Make sure that the mooring anchors are large enough to take the weight of your boat. Many marinas use concrete blocks, or old railroad wheels. If you consider that a one ton block weighs significantly less than a ton when submerged in water and that it takes a 40 foot boat about a ton to be submerged two inches, a 40 footer can easily lift a large concrete block off the seabed. For that reason I recommend using a Helix anchor as shown in the photo on the right. Its holding power is quite phenomenal.

With an 8 to 10 foot storm surge, your boat may be large enough to lift the mooring anchors right off the seabed. If you have any doubts, move to a heavier mooring before the storm hits. A Helix anchor is screwed into the seabed by a diver and is probably the most secure form of mooring I have seen. According to manufacturer’s testing, the results are impressive. Royce Randlett. President of Helix Mooring Systems, said that the Helix results were terminated when they were about to break the measuring gauge, not when the anchor lifted out. He also mentioned that several cruisers now carry a Helix anchor as an additional anchor. They don’t use it for routine anchoring, but if a storm is forecast or they are going to leave their boat for a week or two, they don diving gear and screw the anchor into the seabed.

Another trick is to put fenders horizontally down the side of your boat, in case another boat breaks loose. The fenders may not prevent damage, but if another boat breaks loose and comes down on your boat, it will help minimize it. Then go ashore and watch the storm from your window, not from the deck of your boat.

The Coast Guard recommends that you do not stay aboard during a storm, but if you elect to do so make sure that fuel and water tanks are topped up and your sails are bent on, ready for instant use. The additional weight of a full load of fuel and water will help make the boat more stable. On the other hand, in the event that your boat broke free, a full load of fuel would create quite a mess.

By taking the right precautions before a hurricane strikes you can protect your boat. If you don’t take adequate precautions, you risk damaging or even losing your boat.

Helix Mooring Systems
PO Box 723
Belfast, Maine USA 04915

Phone 207 338-0412
Toll Free 800-866-4775
Fax 207 338-0415
Email: helix@ctel.net


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