The Offshore Voyaging Reference Site

Hurricane Mooring Pennant Photo Article

I have spent my entire life living in places regularly hit by hurricanes: my first fifty years in Bermuda, and a bit over twenty here on the Nova Scotia Southwestern Shore. And for most of those years I have kept a boat on a mooring.

So you might reasonably expect that I would have the ideal mooring bridle all figured out. I wish, but there are way too many variables for that.

That said, here’s a photo article on my latest pennant, and how I built it.

By the way, this is my second version of roughly the same design, so most of what follows has been proved out over two years and two hurricanes, albeit Category 1 to 2.

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Charles Roberts

Great article! Could you share your reasoning on an all dyneema safety pennant? Are you concerned about shock loads potentially damaging/tearing out the cleat or other attachment point on the boat?

Andre Langevin

Great article ! with most of the past nice anchorages now moving to buoys boat manufacturers should start to factory install a strong attachement point at the bow. It would lower center of effort and be less risky for shafing (thimble on the mooring penant so metal on metal). I had installed one while building the sailboat and its a life saver of simplicity.

Andre Langevin

In this case I sourced the 3/8″ (18mm) yellow bridle with 20,900 lbs break load from Hamilton Marine in Maine.

You meant the 3/4… i have yet to see a rope made of spider web susbtance at 20 000 break load of 3/8 diameter !

David Eberhard

John, a great article. A retired rigger would like to make a few comments.

Chafe guard; the polyester tube that you talked about. It works pretty good. If you’re using a short length, say less than a foot, you don’t really need to worry about the difference in stretch between the nylon and the polyester. However, if you’re using a long length of the polyester chafe tube, you need to bunch it up quite a bit so that when the nylon stretches, and it stretches a lot, the load is not transferred to the chafe guard. If it is, the seizings that hold it in place will break in short order. When that happens, the chafe guard may end up no longer where you want it. It may not look pretty unloaded, but it will stay in place. Samson makes a very thick, heavy, dynema chief guard, that works amazingly well. I believe the smallest size is 5/8, or maybe 3/4 inches. I don’t remember its trade name, I retired 11 years ago, but it comes out of their Commercial Marine department. It is truly amazing stuff. The mooring that we kept our boat on had about a 2 foot long leader of mooring chain under the mooring ball. The swivel wason the end of the leader. This was done by attaching the mooring ball to the chain about 2 feet down from the end of it. Thus, when pulled tight, the line never rubbed on the bottom of the mooring ball, the chain did. We never had chafe problems on that end.

Thimbles; a thimble serves two purposes. 1) it keeps the line from chafing on the hardware. 2) a lesser known purpose, is that it keeps the line from making a sharp bend. Hi Tech lines such as Amsteel, can easily loose 50% or more of their strength, if subjected to tight bends, such as you would find in a knot. Ideally, the width of the thimble should be at least three times the length of the thimble. Unfortunately most thimbles do not meet this. Even a 2:1 ratio will be a great help. Suncor makes a line of very heavy duty cast stainless steel thimbles that are relatively inexpensive for what you’re getting. We always used them when making mooring pendants. The stamped metal ones that are easy to find, would occasionally collapse, and then the ends would chafe through the line. The splice on the thimble wants to be really tight. If you can get the line to move on the thimble even a little bit it’s not tight enough.

Splicing Dynema; when, using a Brummel splice,the bury wants to be 48 times the diameter, no stitching is required. Doing it will harm nothing. If you’re doing a direct bury splice, it wants to be 72 times the diameter. Here it is mandatory to do a lock stitch. A lock stitch is different than a seizing. A seizing will create a stiff part of the spice that will not bend easily. Also, being on the surface, it is subject to chafe. A lock stitch will penetrate through the splice many, many times. This will keep the burry from slipping out when loaded and unloaded thousands of times. Try to use a contrasting color. That way you can tell if it’s breaking, or if you want to take the spice apart, you can easily find it to remove it. It is mandatory that in either of these spices you have to completely taper the burry. by that, I mean, when completed, run your hand from the eye all the way into the standing part. If you can feel where the taper ends, you have not tapered it properly. An improperly tapered splice will break at a much lower percentage of breaking strength of the line. It will break at the end of the taper that is not tapered properly.

Any questions, please ask.

Eric Klem

Hi David,

Thanks for the additional info. When we first made up dyneema leaders, I used a brummel with no lock stitching and both pendants had the tail pull out maybe half an inch so that the brummel lock would take all the load until it slipped. It looked like a poorly dressed splice that didn’t lay straight when unloaded. I suspect the cause was the handling of the splice in this application where you are passing it through chocks and bending it onto cleats regularly. We now put lock stitching in per Samson’s instructions and have had no further issues.


Edward Scharf

I am glad you made this article because I agree with using the different parts for what they do best. Too many boats are lost due to chafe. Minor point is I have read in more than one place that the long bury splice is stronger then the Brummel and like you said both need to be lock stitched. Practical Sailor listed the long bury first. I look forward to the next article.

Todd Edger

From my humble experience, the weak link in mooring pendents are the short length. Yes they have a high breaking strength, but under the tremendous cyclic load of a storm they can fail do to lack of shock absorption. If I had a chance to do over I would use nothing less then 20′, same as an anchor snubber.

Philippe Candelier

I like the small floats you are using. Instead, in our mooring field, the recommendation is to use pool noodles all along the mooring lines.
It works great, especially in no wind situation when the boat is doing bizarre move around buoy and tangle the line around it.
But I think it is not doing a very good job cooling the pendant under heavy weather.

Eric Klem

Hi John,

My thinking on the best way to construct mooring pendants is very similar. What you are proposing actually fairly closely follows the MIT study from the 1990’s? where they recommended nylon strop hitched to polyester because dyneema didn’t yet exist. Since we went to dyneema portions at the inboard end, our significant chafe problems have nearly vanished for exactly the reason you state, there isn’t movement anymore. On our mooring pendants, this is 3/4″ dyneema but on our snubber it is 1/2″ and we actually don’t run any chafe guard on that and see no signs of chafe at 500+ nights including some sporty weather. I just made a new set of pendants this year and previous 3/4″ dyneema showed no chafe at the chock and there was only a small amount of chafe on the chafe gear after 10 seasons.

We elected to use double braid nylon instead of a Dacron outer, nylon inner braid as the modulus is lower for the nylon line. Given that this portion is only ~12′ long for us and it is quite large in diameter, we wanted as much stretch as we could get to knock off the load peaks when chain catenary is vanishing. There are 2 downsides that I can think of with the nylon approach. The first is that it didn’t seem easy to buy what we wanted premade so that left me with splicing it myself. The other issue is that nylon is poor in fatigue but the way we are sized should be more than enough for a single storm duration, we just may need to replace after a prolonged storm even if there is nothing visually wrong.

On the backup pendant, I have very mixed feelings on having it there all the time versus adding it. I tend to dislike belt and suspenders solutions, I much prefer a really well engineered belt or suspenders, not both. This would have me agreeing with your method and what I would do in your case. However, for people who don’t have the mooring in front of their own house in a protected cove and plan to be around for any storms, I think it is likely better to have it there all the time. I know that in our mooring field, many people plan on adding storm pendants but very few actually regularly do as they are busy, it is already too rough to get out to the boat, etc. Another issue is that if you can’t add it at the last minute when the wind won’t go calm again, adding a second pendant often results in one of the pendants wrapping around the chain if they are not secured to each other (aggravated by pendant on top buoys which are common here). Finally, many mooring fields require 2 pendants so you don’t get a choice (I have moorings in 2 harbors and both require it). As a result, we keep the backup pendant on all the time knowing that it won’t last as long due to the UV exposure. The key to making it work is to lash it every 1.5′ or less to the main pendant but having it be longer and spreading the length along the pendants so that it never carries load. All the mooring balls around here have the pendant attachment on top and I find that with our 2 pendants of 7/8″ and 3/4″, a 1″ D shackle with lashing the pendants together works great. I would love to use a pear ring but that makes changing pendants really hard as they have to be spliced in place and not everyone owns a press to manipulate the thimbles. I share your concern about thimbles but haven’t removed any yet.

One issue we have had is small mussels have gotten into the backup pendant dyneema braid twice in 10 years. I suspect that this will not help internal chafe. For the time being, I am trying to be better about getting the pendants up on top of the ball when we are gone for extended periods but I have wondered if wrapping it would be better. Obviously your solution of removing it works too.

I am curious what your plan is for replacement interval? Do you have a storm level that would cause you to replace? A UV level? We are doing 5 US Northeast seasons on the nylon and 10 on the dyneema and storing out of the sun for the 6.5 months the boat is out of the water. I have noticed that the ones served by mooring services seem to look a lot worse than ours and I think that they are running them a lot longer and often storing outside in the offseason.

Thanks. If only we could get everyone to get to somewhere near your mooring pendant level big harbors would be so much safer in storms.


Eric Klem

Hi John,

I look forward to hearing more on your thoughts of where to attach the pendants. That is another place where I have mixed feelings and actually have our mooring setup differently than my parent’s which I set up longer ago.


Alastair Currie

Great article! I was not even aware that polyester, or Dacron sheathes were available; I used old fire fighting hose sections. This winter I sat through 60kt gusts in my marina (sheltered from waves) and storm winds were more frequent. For the first time I witnessed a nylon mooring line failure and it is exactly what you described – it was a back up bow spring, secured to the midship cleat i.e. a long run between cleat and fairlead at the bow. Also the line was slightly smaller diameter than my primary mooring lines. It must have been stretching significant distances (relative of course) in the gusts and eventually failed. I tend to keep my boat on the water all year and only lift out every second or 3rd year over winter. I am wondering now if some of the principles in your article could be deployed for my berth mooring lines. This winter my old fire hose sheathes all wore away, the first time that has happened in one winter season. The UK is predicted to have more frequent strong wind episodes, hence your article is very useful.

I’ll certainly be buying the polyester covers (already sourced on eBay in the UK) and likely will make up some berth specific mooring lines along your principles. Decades ago, I used staple spun polyester rope, low stretch, and noticed that the boat did not surge about in strong winds, nor did it shock load the cleats, hence I have always wondered if mooring line stretch was significantly beneficial. Anyway, food for thought.

Tana Bevan

Am diligently attempting to learn from your vast experience and finally understand enough to ask a couple questions (though whether intelligent or not I cannot say) so here goes. Are mooring pendants and while on anchor/on the hook anchor chain snubbers the same? If not, can one modify your mooring pendant construction instructions to snubber-ism and if yes, how? Appreciate you sharing your experiences which at times was hard earned knowledge. Thank you.

Tana Bevan

Thank you. I’ve read & will now post my questions there.