Mooring Warp Diameter

steveej

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A lot of my warps have been shredded whilst the boat was waiting for a few days on the visitors pontoon before being allocated my club berth. 24 hours of exposed force 8 has chafed through a lot of my lines which now need to be replaced.

What do people use for a 32 ft AWB? The previous lines were 20mm which should be overkill. Guess it shows how important it is for the boat to be in a sheltered position.
 
On a boat of similar length on a pontoon but not in a marina, I use 24 to 28mm diameter octoplait lines with tubular webbing on all eyes and chafe points. Although the breaking stain of these lines may appear excessive, the wider contact area reduces the focal loading and chafe. Jimmy Green & Co. sell tubular webbing in various sizes.
 
We are careful about chafe. If it's going to be windy, we moor the boat such that the warps are not rubbing on anything.
 
A lot of my warps have been shredded whilst the boat was waiting for a few days on the visitors pontoon before being allocated my club berth. 24 hours of exposed force 8 has chafed through a lot of my lines which now need to be replaced.

What do people use for a 32 ft AWB? The previous lines were 20mm which should be overkill. Guess it shows how important it is for the boat to be in a sheltered position.

There is a mooring warp size guide on Jimmy's website https://jimmygreen.com/content/44-mooring-warps-size-guide
 
Our boat's a bit longer than yours and we have 14mm lines, as suggested by Jimmy Green. We used to have thicker lines but they were much more difficult to handle than those we have now. Having plenty of thinner lines is a lot more practical than a few chunky ones.
 
We had 20mm nylon as mooring lines but, after a couple of seasons they went rock hard and were impossible to handle. Now on 16mm mulitplait and we have short lengths of clear hose slipped over then at all the chafe points. So far, so good.
 
We use 12 or 14mm lines on our 42 footer - often left by itself for 4-5 months each Winter in a marina.

We have rarely suffered from any chafe even in windy or swelly marinas and have never added chafe protection. I’d have a good look at your fairleads and feel/polish them smooth. I also put rubber snubbers on the shorter lines.
 
I have a heavy (~15T) 42' boat and I use 14mm lines. But I use 3-strand - never, ever braid - and I use doubled up lines when leaving the boat or any swell is expected, so that should a single lie fail the boat is still secure. Not that a line ever has. I also use snubbers for the breast ropes, using the mantra 'springs tight and breast ropes slack'.

Shamefully, I'm still using some of the original warps from 2005 when she was new - the others I have replaced only because I've dropped some overboard / had some stolen / Alzheimer's is setting in and I can't remember where I put them. Why never braid? Because you can't inspect its innards, especially if spliced: it may be - and probably is - fine but I prefer to see the strands. I also use anti-chafe material around the ropes if the lead isn't fair.

But the more important aspect for me is to avoid above all else movement through the fairlead. This implies no stretch in the section between the fairlead and the cleat, which is achieved by (i) don't use Nylon, use polyester, (ii) have only a short distance between the cleat and the fairlead, and (iii) put some elastic (eg snubber, or a length of nylon) between the pontoon / quay-side and the fairlead.
 
34’ Jeanneau SO and I use 14mm 3 strand polyester.

One important property often overlooked is the stretch and elasticity to reduce snatch loading on both the deck and dock fittings.

If you oversize the ability to absorb the snatch load will be reduced. They are also not usually fitted well to the deck fittings.

Better to double up standard sized warp as I do over the winter.
 
I use 3 strand 20mm polypropylene warps because it is cheap & floats. I never pass them through the fairleads, preferring to go from the cleats ( spliced loops), over the gunwale & to the pontoon. At the pontoon cleat I do not double up & return to the boat but have spliced loops through which the line is doubled through so there is no friction.
The only wear I get is when visitors use my berth & pass my mooring ropes through their fairleads.
The rope I use is from 40 No. 7 metre long strops that I purchased at 50 P each from Tilbury docks; so I have plenty to cut & re splice. But they normally last 3-4 years unless someone nicks a couple, which happens from time to time.
As with the 3 strand nylon ropes I use when visiting other ports, it is not the strength of the rope, it is how they wear that is the problem.
I find braid on braid pretty poor for that use as once there is the slightest nick in the outer covering it is gone.
 
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I agree with Daydream Believer, the problem of mooring line failure inevitably arises from wear due to chafe and is not due the original tensile strength of the line. For this reason, I use mooring lines designed to cope with chafe, i.e. the largest diameter that will fit fairleads and cleats, combined with anti-chafe measure, such as tubular webbing, on loops and other points of contact. I believe that the issue of elasticity or "give" is best dealt with separately to the diameter of the lines, by the use of compensators, such as rubber or helical springs or other physical arrangements. It should also be remembered that doubling the lines reduces the modulus of elasticity in the direction of extension of the lines by half, akin to the effect of increasing the diameter of the line. Incidentally, I have found that large diameter "Octoplait" or similar 8 strand lines are less prone to hardening than the alternatives.
I have used such arrangements for 30 years on pile and pontoon moorings all year round, without ever having a mooring line part during use.
 
For our 44 foot AWB I use two solutions. Those nice black mooring lines that are very stretchy are good for short spells when we are on board; SWMBO finds them easier to handle and coil. I think mine are 18mm.

Home mooring is on a river pontoon near the mouth of the Hamble. It is quite exposed to an easterly and, more significantly, to wash from every single passing boat. A semi-displacement MOBO at the 6-knot speed limit creates serious wash; in my personal view those driving such boats near pontoons should kindly limit themselves to 4 knots. If you drive past boats and see them bucking up and down, you went too fast.

So when unattended we use 20mm polyester 3-strand, doubled up properly. I don't think the braided lines would hack it in terms of chafe. In case not clear, that means start from the yacht and go ashore, fully make off on the cleat, then back to the yacht and make off again under similar tension. That's for breast ropes.

I have plenty of room fore and aft so I go an extra cleat or two away from the yacht, creating a very acute angle and 1/2 boat length of span; I figure that gives me enough stretch even allowing for the doubled-up line. I have sat watching the moorings as aforementioned MOBOs go past; there's no snatch. The one time I went to bed with the breast ropes perpendicular, there was the most alarming snatch.
The only disadvantage is she does get blown well off the pontoon in a westerly, which I regard as no problem at all; easy to heave on a line in order to climb aboard.

Springs - I mount two separate bow and stern springs. Two are 20mm polyester 3 strand again; the other two are currently whatever I have left in the locker!

Following extensive research I have come down on the side of polyester vs nylon, for greater durability. I would always favour 8-plait over 3-strand but it's expensive and so I will await natural life replacement. I have found with 8-plait (on my nice new kedge) that you need an extra turn on the cleat before you can hold it with confidence under load.
 
My 5-ton 34 doesn't have fairleads as the cleats don't need them, but on a previous boat we always put a hose over the line for other than light overnight moorings. I imagine that a snubber reduces chafe to some extent but protection is really the only answer. For a shore cleat a series of turns will be ok, but for a ring I often see boats moored with only either a simple turn or a double turn, which is only marginally better. For this purpose, and also on mooring buoys as visitor, I add a cow hitch to my usual bowline or round turn etc.
 
Our boat lives on a swinging mooring.
Leaving it unattended long term on a pontoon is scary by comparison. I'd want to sit with it through at least the first gale.
 
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