What ropes?

A

adrianm

Well-Known Member
Joined
16 May 2001
Messages
529
Visit site
My new boat is almost ready and I need to get the ropes sorted for the delivery voyage. She's a 16m steel motorboat weighing in at 35 tonnes. What size (and material) ropes would be best. I have all sorts of conflicting information to hand at the moment and was hoping someone could give me some "real world" advice.

Thanks.
 
You really need to be a bit more specific about what ropes you are talking about. Are you referring to rope used to attach to chain for anchoring, rope for securing boat alongside the jetty, rope to tie up your christmas presents?
 
Mooring ropes; springs etc.

Yes I do know how to handle her. It's just that there is a huge difference between what I originally planned to use and what I've been told by a few "experts" since.

Personally I would be more concerned about the sort of person who doesn't seek advice and just charges blindly ahead.
 
I was planning to have 4 ropes of 60ft in length and 2 of 120ft in length all 3/4" nylon.

Talking to some people at the marina they said nylon is useless for warps and spring. They advised to use 1/2" polyprop instead and to have 6 ropes at 100ft instead.

Now that goes against everything I know but they've been at it a lot longer than me so thats why I'm now more than a bit confused.
 
I'd use Nylon or polyester for warps & springs partic with such a heavy boat and definitely not polyprop(only used where a floating line is required) think you're looking at 20mm + so 3/4 is probably a tad on the light side. Look at
Jimmy Green
 
I'm no expert, so take this for what it's worth, an opinion with no warranties!.

"High elongation characteristics make nylon ideal for applications where shock loading occurs, such as mooring tails." (Marlow Ropes Website) I think I'd trust them rather than some bloke in a marina!

I believe polyprop is more resistant to chafe and is probably stronger, for the same size, but is less elastic. My boat is a little plastic one weighting in at 2 tons, so it's not quite the same, but I prefer nylon. I don't want my cleats snatched out of her when some inconsiderate b*****d lays a 4ft wake across the pontoon! You can put plastic tube over the lines where they pass throught your fairleads to protect against chafe.

3-strand nylon rope is fairly easy to splice and handle, Octoplait has similar strength, will probably be more supple, but splicing is a bit more complex. 18mm nylon has a breaking strain of around 6.7 tons while 22mm goes up to 10 tons. Anything bigger is going to start getting harder to handle, cleat off and so on. If you only ever moor in sheltered marinas, you could probably go down a size or two, but having seen boats bouncing off their lines in a swell - or heavy wake, I'm a great fan of strong mooring lines!

As far as length is concerned, my main mooring lines are just too short to foul my prop if from the forward cleat. Springs are longer, but I tend to rig them onece I'm attached, so there's less risk of them going round the prop.
 
<ul type="square"> From Jimmy Green:

Boat length . . . . . . . 16m
Main Anchor . . . . . . . 12mm chain
Main Anchor warp . . . 20mm Octoplait
Kedge warp . . . . . . . 14mm Octoplait
Mooring Alongside . . .18mm 3 strand polyester
. . . . . . . . . . . . . . . .18mm Octoplait or 3 strand Nylon
. . . . . . . . . . . . . . . .18mm Dockline (hybrid nylon braid with polyester braid cover)
. . . . . . . . . . . . . . . .24mm 2 or 8 strand Polypropylene
[/list]
Now that gives you the numbers but doesnt really answer the best type of rope for what pupose.
Anchoring/kedge is easy as that needs to be stretchy to take the snatch loads and thus Nylon is best. Octoplait is the best type of nylon for anchoring cause it remains flexible.

However, mooring alongside is a different matter, and needs to be looked at in relation to where the boat is moored, amount of traffic by other boats, and behaviour of your boat in wash. Nylon will reduce the snatch load on cleats, but there are a couple of reasons for not using it. Firstly the very stretchiness that made you choose it in the first place will also cause high chafing at the fairleads, and this caught lead to premature failure. Secondly the elasticity can also cause a surge effect (especialy in the springs) where the boat ends up in a increasing movement forward then aft powered by that elasticity to the point of failure.

To get the same strength in Polyprop will need a much larger diameter rope, and it is more susceptible to UV degradation. Thus my recommendation is that all the lines should be polyester or the hybrid polyester/nylon braid, and that you should add rubber mooring snubbers
SnubberEng.JPG
 
4 x 4 times her length, min

personally we use plaitted for comfort of handling, would go for the better qualities (last longer as well)& size as the momentum/energy at this weight can be high.

can also vouch for jimmy green. good service.
 
You must log in or register to reply here.

Share this page

Top