Docking and other ropes

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Docking and other ropes

Docking lines and other ropes.

hi all, having recently purchased Star and preping her for next year I want to replace practically all of the ropes. I’m in a quandary about breaking strain, in particular for docking lines:

10mm - 1835 kg

12mm - 2651 kg

14mm - 3976 kg

16mm - 4180 kg

but also the other other lines any advice would be useful.


rick.jones's picture
Hi Keith

Hi Keith

There should be no reason to use anything heavier than 10mm for mooring. I don't think I've seen a Mac with even 12mm lines. On my previous X my main lines were 8mm twist.

I assume you're aware you need to use the correct type of rope for docking? I.e. a rope with some give, not rigging braid. Either classic twist, or modern purpose-made docking line.

Rick Jones (Treasurer) 1994 Mac 19 "White Lightning", Isle of Wight

david.claassen's picture
Rick's advice is, as always,

Rick's advice is, as always, spot on.

I would only like to add that you need to consider what kind of docking situations you might find yourself in. I use up to 4 mooring lines if I am in a finger dock and need to rig springs. Additionally, if mooring rings/cleats are dodgy or sparse, or if you are mooring on a river using pins, you might need quite a long line or two. I have two rather long docking lines in my kit. I don't use them often, but when I do, nothing else will serve.

David Claassen

"Logan's Run"

2006 26M

I agree with the comments

I agree with the comments above but would add that the breaking strain of the rope is not the main reason ropes break - most mooring ropes fail because of the knots used or chafing. All knots reduce the breaking strain considerably (by about 30% to 50% depending on knot and rope type) but chaffing is an even bigger issue. I noticed that in our marina last week many boats were moored to fixed metal rings with either a loop passed once through or a single turn and a couple of half hitches - these are likely to chaff through over winter with tidal and wave action. The best knots to use on a fixed metal loop is a round turn and two half hitches - the round turns stop or minimises movement of the rope and prevent chafing and any turns more than two don't increase the strength of the knot. For long term fixed moorings a proper spliced in metal eye and a shackle are the safest option but even these need periodic checking for wear.

On our Mac 26M we use 12 mm soft twist mooring lines - anything larger won't fit our mooring cleats properly and we find this size easier to handle than smaller diameter dock lines. These are used on a finger marina mooring for both springs and fore and aft lines to good effect all year round (we leave her in the water over winter every other year.)

A couple of good long mooring lines are always useful to have handy when you need to moor outside other boats or on a high tidal key though - we carry two approx 30 meter lines as well as a spare anchor warp that can be pressed into service if needed for mooring.

Regards Mike C - Tarka 26M

leigh.ross's picture
I’ll add my 2p worth. As

I’ll add my 2p worth. As pointed out above. Breaking strain isn’t an issue. Look at your cleats. Would you really hang 1800kg ( 10mm breaking strain ) on it and expect it to hold? The entire boat doesn’t weigh that

So shock absorbsion and chafe resistance will be the deciding factors. 3 strand nylon would work well assuming measures to mitigate chafe are taken.

Leigh Ross


0777 558-4561

1990 MacGregor 26S Ptarmigan 

1992 MacGregor 26S Pelican 

There are anti-chafing

There are anti-chafing solutions but the cheapest and easiest is to cut a couple of lengths of old plastic/rubber hose pipe, split it if necessary, and fit over the mooring warp and place in the appropriate place or slide the warp through and position accordingly.

There are also shock absorbers available from good chandlers (or on-line) and they don't cost an arm and a leg but as a Mac is light, when compared to a keel boat I don't think a shockabsorber would be much use.

You can, of course, visit a chandlers on go on-line to see what solutions are available.

I wash all my ropes in fresh water at the end of each season. Gets rid of grit and salt, makes them softer to handle and they look better and last longer. Don't put them in a washing machine though even if wrapped up in a pillow case or similar. They don't like the spin.

Good Luck with it all.

Simon Armitage

Sowenna 26M.

Hi Guys,

Hi Guys,

Thanks for the great advice . I will be ordering new ropes now that I have the info. Thanks again