What size mooring warps?

[wazza]

Our boat weighs around 7 tons. I'm going to be buying 4 new dockline mooring warps for our pontoon marina berth, my question being what size do you think I should get??

14mm@ 3550kgs
16mm@ 4750kgs
18mm@ 6100kgs

I'm thinking 16mm is good, 18mm overkill and 14mm is sufficent or......

 

[sailorman]

Our boat weighs around 7 tons. I'm going to be buying 4 new dockline mooring warps for our pontoon marina berth, my question being what size do you think I should get??

14mm@ 3550kgs
16mm@ 4750kgs
18mm@ 6100kgs

I'm thinking 16mm is good, 18mm overkill and 14mm is sufficent or......

i think your assumptions are ok

 

[CAPTAIN FANTASTIC]

I would go for 18mm; little difference in physical size and money between 16 and 18 but the 18mm is much stronger and perhaps longer lasting.

 

[westernman]

Chafe is the danger for mooring ropes. I would go for as big as you can get through your fairleads, tied to cleats etc.

Having chafed through 5 warps two years ago I went and bought a 220m reel of 22mm. This is lasting very well and I also now have the critical chafe points protected with fire hose.

 

[VicS]

See the guide on Jimmy Greens website http://www.jimmygreen.co.uk/p/technical/mooring-warp-size-guide

Before going for the overkill sizes be sure your cleats are large enough for it.

 

[wazza]

See the guide on Jimmy Greens website http://www.jimmygreen.co.uk/p/technical/mooring-warp-size-guide

Before going for the overkill sizes be sure your cleats are large enough for it.

Thanks, just looked at the site and they say, as I thought 14mm is ok for our size boat, so as to be a little more cautious I will go for at least the 16mm that's suitable for a 40 footer...

 

[westernman]

Thanks, just looked at the site and they say, as I thought 14mm is ok for our size boat, so as to be a little more cautious I will go for at least the 16mm that's suitable for a 40 footer...

Check your cleats and fairleads.

 

[Coaster]

Our current 14mm mooring lines are now 3 years old. The 34' boat, true displacement in use about 8 tons, is in the water for 8 months of the year. There is very little chafe evident on the lines.

14mm mooring lines are easier than larger sizes, to handle and stow.

We use 2 bow lines, 1 stern line, 1 spring from boat centre cleat to finger pontoon end cleat and 1 line from boat centre cleat to finger pontoon cleat continuing on to bow cleat, effectively 6 lines in total.

Our marina berth is sheltered. It might be a very different story in a different location.

 

[Talbot]

My boat is 39ft cat. I use 14mm with one bowline and one stern, but two foresprings and two backsprings.

 

[Tranona]

14mm is sufficient from a strength point of view. As others have said it is chafe that is the problem - that is losing strength by wearing through at critical points. If your berth is exposed and you get a lot of movement is worth considering using snubbers of some sort.

 

[ukmctc]

If its chaff then put some plastic hose at the point of chaff and that'll sort that.
My boat is 11 ton, Moody 33 MK1 and I use 14 mm mooring lines with no problem.

I have 4 x 10m, 2 x 30m, 1 x 50m and that covers most mooring in dock/harbour or marina that I have came across. They have held in all weather including F10 in Shetland with no problems.

 

[wazza]

11 tons for a Moody 33.. blimmey
.. We have a Najad 343 & she weighs 6.5-7 ton, and we've had 20mm standard warp so the cleats are ok, we are pretty sheltered I'm buying these warps called "docklines" but will put snubbers on them anyway..

Thanks for everyone's input

 

[Tranona]

11 tons for a Moody 33.. blimmey

Thanks for everyone's input

Think he is referring to its registered tonnage, which as you no doubt know is not connected with displacement/weight. Expect it displaces around 5-6 ton(ne)s

 

[VicS]

Think he is referring to its registered tonnage, which as you no doubt know is not connected with displacement/weight. Expect it displaces around 5-6 ton(ne)s

Absolutely. Displacement of 4.69 tons according to my book.

 

[KenMcCulloch]

With a bit over 8 tons displacement we also use 14/16mm lines. In the recent extreme weather (3rd January) two very substantial warps broke, not through chafe (although that may have contrubuted to some extent) but overload. One at a sharp turn through an enclosed fairlead, the other at the pontoon cleat. The rope near the point of failure had the 3 strands 'welded' by the heat and pressure created under breaking load conditions. I have never seen warps break before and I don't think there is anything wron with our / your thinking about appropriate sizes, my cautionary tale is simply that.

 

[srah1953]

With a bit over 8 tons displacement we also use 14/16mm lines. In the recent extreme weather (3rd January) two very substantial warps broke, not through chafe (although that may have contrubuted to some extent) but overload. One at a sharp turn through an enclosed fairlead, the other at the pontoon cleat. The rope near the point of failure had the 3 strands 'welded' by the heat and pressure created under breaking load conditions. I have never seen warps break before and I don't think there is anything wron with our / your thinking about appropriate sizes, my cautionary tale is simply that.

I have a theory that if one used two lines at each mooring point, with one being a much smaller diameter than the "main" mooring warp, with this light line being shorter than main line so that it will stretch a lot and absorb a lot of the pressure before the main line is called upon.
No doubt someone will put me right!