Dock Lines

[GMac]

Interesting to see the 'old' stuff seems to last longer than the new stuff. How many things does that apply too these days.

You are quite likely quite right with your theory there on the cars bungy, HelloSailor. Salt crystals are not rope friendly.

[JohnnyC]

This discussion has been a gold mine of information. Like Island Mike, we are replacing 3 strand nylon dock lines (that I believe came from a retired anchor line). In our case the lines are getting replaced because of chafe (sp?) which seems to have occured primarily at the fairleads. How does the megabraid line (octoplait?) stand up to chafe? How about double braid vs 3 strand? I suspect part of our trouble was the lines were actually oversized for the fairleads. They were 3/4 in. This seems excessive for a 35 ft boat at 15,000 lbs. Then again, with a full keel and strong currents by the dock, perhaps 3/4 in is appropriate? What do you think?

[Rick]

Your boat needs to be able to move when current surges or wind gusts hit in order to minimize the amount of strain on the dock and deck cleats. Energy absorption devices in your dock lines allow this movement to occur in order to integrate the peak levels of strain down to a manageable level over time.

Other than discrete energy absorption devices there is the built-in stretch of the nylon normally used for such a purpose, otherwise everyone would use polyester lines (which you can do quite nicely without attendant chafe IF you use discrete energy absorption devices of sufficient energy absorption ability).

Plaited lines appear to have the most energy absorption capability, then 3-strand and last double-braided nylon. The amount of stretch of double-braid nylon is not sufficient alone without also using discrete energy absorption devices, in my opinion. Just because double-braid is nice on your hands is no reason to use that in a nylon line, just use polyester if you like the looks and feel of double-braid. In addition, double-braid nylon can be spliced only when new and, even then, with some difficulty as compared to polyester. Plaited and 3-strand lines can be spliced even aftrer being used and stretched and saturated with saltwater.

Although not commonly done, it is best to use polyester from any cleat to outboard of any fairlead in order to practically eliminate chafe. Use nylon from there and you will not suffer the chafe problems and still have the requisite stretch. I believe that plaited line offers a slight advantage in the chafe department over 3-strand and also feels better on the hands. I doubt that I'll buy any more 3-strand now that plaited line is becoming so available from various sources.

[Talbot]

I nearly lost my boat when the lines chafed through in a storm. I no longer have that problem on my permanent berth cause I use a length of chain at each end of the mooring rope, from cleat to outside the fairlead, and to attach mooring rope to the cleat on the dock. It also means that if these permanent lines fall off the dock into the water, that they sink straight down and are not a problem when coming back alongside.

[GMac]

Originally Posted by JohnnyC

This discussion has been a gold mine of information. Like Island Mike, we are replacing 3 strand nylon dock lines (that I believe came from a retired anchor line). In our case the lines are getting replaced because of chafe (sp?) which seems to have occured primarily at the fairleads. How does the megabraid line (octoplait?) stand up to chafe? How about double braid vs 3 strand? I suspect part of our trouble was the lines were actually oversized for the fairleads. They were 3/4 in. This seems excessive for a 35 ft boat at 15,000 lbs. Then again, with a full keel and strong currents by the dock, perhaps 3/4 in is appropriate? What do you think?

Megabraid (made by Samson) is not actually an Octiplait it's a 12 strand and may I say, damn sexy stuff, price excluded. Way to flash for use as marina lines but good as dock lines.

Marina V's Dock lines in our speak.
Marina lines are fixed to your marina (maybe 'dock' in your speak) and stay there. This is the boats permanently parked place.
Dock lines are kept on the boat for use when rafting up, fueling up and so on. For use while using the boat.

The construction of the rope does not have a huge bearing on the chafe resistance more the fibre the rope is made from.

Best to worse of the more common fibres when talking chafe resistance:
Vectran
Kevlar
Dyneema
Polyester (Dacron is another name)
=Nylon (Polyamide or Polyamid are other names)
= some higher garde polyprops
Ployprops

35fter in a marina 3/4"/20mm is what I'd use. For Dock lines I'd go down to a 5/8" / 16mm.

For marina lines just use a 3 strand purely for price reasons. For dock lines I'd look at the octiplait.

Good post by Rick above which explains a few things well. I'm not sure I'd muck around splicing polyester to nylons and so on but them maybe I'm just lazier

[hellosailor]

GMac-
"Marina lines are fixed to your marina " So, that's for folks who are rich enough to have two sets of dock lines (one to take, one to leave) but too poor to have their own dock hands, waiting for them at home, with freshly cleaned mooring lines for their return?

And such poor folks are allowed to *sail*? Shocking.<VBG>

[Talbot]

I have permanent dock lines so that I always get the boat into the right spot,

One problem with a cat and a finger pontoon berth, is that most finger pontoon widen out as they get close to the main pontoon, in order to provide more resistance to twisting. This is fine for a normal mono cause the shape of the bow mimics the end shape of the finger pontoon, but provides a problem for a cat which does not conform to the same shape.

[Rick]

GMac, it is relatively easy to attach a polyester anti-chaffing snubber to nylon. An eye is spliced into an end of the polyester. Either an eye is spiced into the attached end of the nylon or a "squar knot" gets formed when attaching the nylon to the polyester eye. This makes for a 100% strength of the weakest line used.

Such attachments work well for anchor rodes when one desires to eliminate shackles altogether. Polyester is spliced directly onto the last link of the chain and "interfaced" to nylon with eye-to-eye attachments. See photos under "Rick".

[GMac]

Us 'rich' people do like 2 sets of lines . $80 your money?? Yeap I'm lazy enuff to spend that for a marina only set. Lot less drama when parking up.

Rick - I know your idea and it is a goodie but again I'm to lazy and are lucky enough to have a large range of mooring/docking things I can swap around at will so chafe is never an issue for me. Not to mention a large pile of flash anti-chafe sleeving

[JohnnyC]

Thanks Rick, GMac, Talbot and all for the education.
Rick, the excellant photo made it easy. The apparatus looked complicated at first, but with a bit of thought it came clear. It is simply a couple of lines joined with loops to make use of the best qualities of two different materials.
3-Strand nylon is the best for marina lines, with polyester at the ends if chafe remains a problem. Chafed lines can be shortened to chafe free lengths with eyes on the ends. Then polyester bits (also with eyes) can be attached for additional chafe resistance where lines pass through fairleads or regularly chafe.
Octoplait or similar single braid nylon can be used for traveling dock lines. It stores well and is equally strong with better stretch, but may be a bit pricey for everyday use.

Sailing is good.