Preparing Your Boat for a Tropical Storm

Posted by By Darrell Nicholson at 01:01PM - Comments: (10)

Boats doubled up on dock lines in local marinas as storm surge sets in.

With Hurricane Dorian threatening Florida and possibly the Carolinas, it is time to start activating your hurricane response plan.

You might want to start with our July 2008 report, “Lines, Snubbers, and Other Gear for Battening Down Ahead of Storms.” Safety expert Ralph Naranjo’s first-hand account of his storm preparations “Tropical Storm Dos and Don’ts” and “How to Help Your Boat Survive A Major Storm” should also be required reading. These articles all discuss the first line of defense against a hurricane: secure your boat in a boatyard or hurricane hole.

But what if you have no option but to stay on a municipal mooring? Will these hold? Although we've never put much faith in mooring systems that we didn't have a hand in designing and installing, there are some mooring systems that deserve a closer look.

One class of product that has been gaining more attention in the wake of Hurricane Irma is the elastic mooring systems being used in Florida's municipal mooring fields as well as throughout the Caribbean. Florida's mooring systems were installed as part of a statewide pilot project to regulate anchorages and to minimize environmental damage to the bottom. As Practical Sailor's report on mooring systems revealed, all but one of the moorings in Marathon, Florida were still intact after the storm. Irma tore dozens of boats free from their moorings, but most these failures were linked to the owner-supplied pennants.

The Eco-mooring uses a sheathed, elastic rode. Other systems like the Hazelett and Seaflex systems take a similar approach to absorbing shock loads.

Three manufacturers offer products in this class. Eco-mooring System is effectively a super, heavy-duty bungy cord. It operates on the same principle as others like it, including the Seaflex Mooring System and the Hazelett Mooring System. These mooring rodes incorporate an elastic rode that allows mooring fields to pack more boats into smaller spaces. The elasticity also helps reduce shock on boat hardware.

We haven’t yet tested these systems, but we have taken a close look at how these moorings fared in Hurricane Irma. Prior to that report, the second most recent discussion of mooring holding power was published in 2009.

A couple other mooring-related products on our radar are the new helix-type mooring anchors offered by the same company that sells the Spade anchor in the U.S. These also held very well in Hurricane Irma. We should mention that similar screws installed by a professional contractor here in Sarasota, Fla., initially failed to meet specified pull tests, so it is important to carry out post-installation load testing.

As marine surveyor Jonathan Klopman pointed out in response to our discussion of elasticity in anchor rodes, the topic of how much stretch is a good thing is a “hot” topic so to speak. Heat-induced friction in nylon rode, it seems is on everybody’s mind.

New England Rope's Cyclone Mooring Pendant incorporates two types of cordage.

Because of this, we are also interested in evaluating England ropes’ approach to storm moorings. In the New England Ropes system, the cyclone mooring pendant (set between the mooring ball and the boat) is made of two components—a length of low-stretch Endura 12 to handle abrasion on the boat and a high-grade nylon mooring pendant that goes from it to the mooring ball. New England Ropes has also launched a new line of chafe protectors, which we will be pitting against the best chafe protection from our last chafe-guard test.

There’s plenty to say about this topic, but the most important thing is this: The time to plan your hurricane strategy is long before the storm hits.

Comments (10)

"With Hurricane Dorian threatening Florida and possibly the Carolinas..."

Happy to hear Georgia will be spared!

Mark B.
Atlanta, GA

Posted by: | August 30, 2019 6:31 AM    Report this comment

This is good. We have a Catalina 30 up a river off of the Chesapeake.
From my 65 years of sailing, I would say this:
You can get more and better advance weather warnings than ever before.
Weather seems to be more aggressive in the last 5 years than I can remember.
To ready for a storm, absolutely do remove all sails.
Don't forget the hatch in the head.
Dock lines, springs, and extras crossed to the other side.
Be sure to secure your boom to minimize swaying.
I fortunately do not have the big water exposure that some of you have, and I have new bollards deep in the mud, so I can be comfortable about dragging. However, in a slip, your scope is shorter than at anchor, and I had seen back in 2003, I think, when storm surge caused some to sink at the pier, because their lines between boat and cleat or bollard were too short.
Last thing, figure this all out in advance. That way, you will have the opportunity to re-think your plan and replace anything that shows signs of being a weak link.

Posted by: Otis P. Driftwood | August 13, 2019 8:42 AM    Report this comment

I keep my Beneteau Oceanis 321 on fixed steel docks at Edgewater Yacht Club in Cleveland, Ohio. The docks are exposed to winds from every direction except south. We rarely get winds gusting over 60 knots but it does happen. We do get surge. Every few years we get the tail end of a hurricane. Superstorm Sandy caused a lot of dock lines and cleats to fail in the Cleveland area. Storms and squalls with winds gusting over 50 knots happen at least once a season.

We have four point tie ups at our slip. We have been using one high grade 5/8" three strand nylon dock line from New England Ropes in each of the four corners. These are the boat's primary dock lines. We use Davis chafe protecters on the two forward lines at the chocks. Each of the lines has a 16" Davis Shockle.

In addition the boat is tied up with high grade New England Ropes 1/2" three strand nylon spring lines fore and aft, port and starboard. We have midship cleats.

The boat has six factory installed chocks with nylon rollers to reduce abrasion. Two are midship and the others are in the four corners.

I bought the boat, the docklines, the first pair of Shockles, and the chafe guards in March 2015. I bought the second pair of Shockles last month to help manage the increased fluctuations in water levels. The are attached to the 5/8" corner dock lines with a clove hitch. The boat is in the water from May through the last half of October. There has been zero line or cleat failures. I give the combination of spring lines, the Shockles, and the three stand nylon line credit for helping control the boat's motion and absorbing the shock loads when the winds and the surge are high.

Posted by: mark2 | August 8, 2019 12:07 PM    Report this comment

The non-stretch bit of line through the chocks to reduce chafe by reducing motion is well-proven by rock climbers for over 50 years. Although the ropes they use are some of the highest stretch (to absorb shock), the short runners that go to anchor points have always been non-stretch to reduce chafe. When Dyneema arrived on the scene, it took over the market withing a few years and is now used almost exclusively. For heavy duty applications, it is sometimes covered with loose fitting (so it can move) tubular webbing chafe gear.

Motion through the chocks or over the roller is very bad. Many builders locate cleats well back from the bow for convenience, but that allows a lot of motion (resulting in friction) when nylon stretches under high load. It's not something you notice on a nice day.

Posted by: Drew Frye | June 10, 2017 8:40 PM    Report this comment

This article is mixing apples and oranges, starting with photos of boats tied to a dock and then a discussion about mooring buoy anchoring systems...they are very different. As someone who has successfully moored boats (San Juan 28 and Tayana Vancouver 42) to a buoy in Puget Sound since 1995 I have learned four things: 1.) A mooring is only as strong as its weakest part which can be as simple as 25 cents worth of seizing wire; 2.) It must be immovably secured to the bottom...anything that can drag will drag eventually and that includes concrete blocks; 3.) Like everything else, it will require periodic it simple enough to do yourself; and 4.) A multiple leg mooring system design has built-in backups should one leg fail, single leg systems do not.

~ ~ _/) ~ ~ MJH

Posted by: MJH | June 9, 2017 11:32 AM    Report this comment

PS July 2016 studied dockline forces and gave some examples based upon direct measurement. There were two basic recommendations: first, add a full compliment of spring lines (fore and aft on both sides) with just enough slack to allow for storm surge. They reduce the forces by reducing the motion of the boat in the slip and by sharing the load, and they add important redundancy if something fails. Because of the nature of fatugie and chafe, reducing force by 1/2 will increase line endurance by at least 10 times. Second, dock lines should be sized about the same as the anchor rode for storm use. See ABYC H-40 table 1 (the most commonly referenced guidance). Finally, chafe is a combination of many factors, not the least of which is the presence of sharp edge and abrupt turns through the chocks or on the dock edge. Use tubular webbing or other durable chafe gear, and keep the turns as gentle and few as possible.

Posted by: Drew Frye | June 8, 2017 1:35 PM    Report this comment

I'd like for PS to comment on correct sizing of anchor rodes and dock lines from the perspective that some stretch is desirable...but not so much to build up heat across a chock. Oversized lines give no protective shock absorption.

Posted by: Wayne Richard | June 8, 2017 8:50 AM    Report this comment

I'd like for PS to comment on correct sizing of anchor rodes and dock lines from the perspective that some stretch is desirable...but not so much to build up heat across a chock. Oversized lines give no protective shock absorption.

Posted by: Wayne Richard | June 8, 2017 8:50 AM    Report this comment

All good data. The fundamental violation I see repeatedly is boats left in slips or on moorings with sails still on roller furlers. You must absolutely take all sails off.

Posted by: MARK H | July 2, 2012 9:18 PM    Report this comment

Having had a brand new 1" bridle break, and the next year losing the boat to a sustained blow with new bridles, I can claim a certain experience. Here's what I discovered after making the changes and weathering Hurricane Irene's NE quadrant with just a little chafe. USE A LONG BRIDLE. Your boat cannot stay on a mooring if it rears up, instead of pulling back. We quadrupled the length. I was advised that the minimum length is 5 times the freeboard plus the distance from the chocks to the cleats. The boat is 43 feet long. In a storm, the front end goes up in the air ALOT! The line cannot make a turn in radius so small as that going over the edge of the deck or chock. If the boat pulls back, the radius is much bigger.

Posted by: DAVID 0 | June 30, 2012 8:04 PM    Report this comment

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