Dock line size question?

[nathan007]

Thanks alot for your replies!

From what i can see, i have double braided nylon dock lines, i guess the size would be 5/8 which seems right for the size/weight of the boat. I just want to make they are 5/8 sure because i want to buy a new one since i noticed a slight wear mark on one of the one i have at the moment, and i want to match it with the rest of the lines i've already got.

Most important, i want it to match for the snubbers i plan on buying, since the boat spends alot of time at the dock, and some days it can be really "rock and roll" weather.

The 5/8 lines are alright for the cleats we've got, i can tie maximum 2 lines per cleat, and honestly, it's tight fit!

I use two lines for the front , one spring line for the front, and one rear line for rear and spring.

My older and smaller hunter 31 clearly uses 1/2 lines which are wayy easier to move around hehe.

Sorry for my english, it's not my first language!!

[Mirage35]

My thanks for the replies as well - I've been working through the same thing.

My 35' boat came with 3/4" dock lines which are clumsy to use and just too big for the cleats on the boat and our home port dock. I'm moving to 1/2" and at the same time going for some longer lines so they can be used for long springs or other purposes.

[Steadman Uhlich]

Originally Posted by David M

Half inch is fine. Just don't tie it up using only two lines. Four lines minimum. 6 lines would be ideal.

As others have said, chafing will do a line in long before the line parts because it reached its breaking strength.

One of the problems with unnecessarily large diameter lines is that if you want to tie two lines to one cleat, sometimes you will not be able to tie a proper cleat hitch because one line already takes up too much of that cleat.

Think about this. If your dock line has 4 times the strength of your dock cleat, then what is the point of having overkill dock lines when it is going to be that easy for your dock line to pull the cleat out of the dock? Some dock cleats are only held in with lag bolts screwed in an inch or two into the wood and are not through bolted.

very good points.

Ran into this problem recently. The Dock lines were too thick (felt like an inch braided ) for the deck cleats, and really "oversized." . And being heavier lines, they were harder to handle, more difficult to coil, harder to toss up to a person on the higher than the boat commercial Dock, heavier to carry forward on the boat, took up more space in the locker, etc.

[DumnMad]

I agree ⅝ is good. Re chafe, make sure your hardest working lines have a loose back-up line, especially if you leave the boat for long periods. Its also comforting to have a neighbor who will check your lines for chafe after a big blow.

[UNCIVILIZED]

Ensure that your cleats, their fasteners, backing plates, & the deck, are up to the job. As sometimes it's not the lines which fail, rather, a piece of the deck will pull out along with the cleat under high load. Or in rare instances, the cleat itself, or it's fasteners may fail. And of course make sure that you have chafing gear which is more than up to the task.

IMO it's also prudent to have a spare dockline (or two) stowed somewhere on deck, where it's easy to find. In case one of yours parts, & a kind neighbor is looking for one with which to resecure your boat. As I long ago lost track of the number of times I've done this for others.

The stowage bins in cockpit coamings are good places to keep such lines. And the lines needn't be shiny new ones, just servicable. In case someone with less scruples decides to walk off with them. But in any case, it also helps to have discussions with your dockmates on; securing vessels, where spare lines are stored, POC information, & bilge emergencies.
That way if there's an emergency, you already have an agreement in place, along with a way to reach folks. As well as contacting them through the marina.

[TheThunderbird]

Springs are longer and can be of a smaller size.

The main line is usually paired with a second spare, just in case.

Old halyards have little elasticity, but I can use them as 2nd tier with strong winds. Their lines have a bit more slack

Worn out lines are shortened to loops used in large bollards, so your double line is easier to retrieve and has less chafe.

I usually board on commercial jetties, no service.

If you miss cleats amidship, install them!

[HankOnthewater]

Originally Posted by UNCIVILIZED

Ensure that your cleats, their fasteners, backing plates, & the deck, are up to the job. As sometimes it's not the lines which fail, rather, a piece of the deck will pull out along with the cleat under high load. Or in rare instances, the cleat itself, or it's fasteners may fail. And of course make sure that you have chafing gear which is more than up to the task.

IMO it's also prudent to have a spare dockline (or two) stowed somewhere on deck, where it's easy to find. In case one of yours parts, & a kind neighbor is looking for one with which to resecure your boat. As I long ago lost track of the number of times I've done this for others.

The stowage bins in cockpit coamings are good places to keep such lines. And the lines needn't be shiny new ones, just servicable. In case someone with less scruples decides to walk off with them. But in any case, it also helps to have discussions with your dockmates on; securing vessels, where spare lines are stored, POC information, & bilge emergencies.
That way if there's an emergency, you already have an agreement in place, along with a way to reach folks. As well as contacting them through the marina.

Uncivilised got it 100% right, and many of the others as well who said it is hardly ever a line that breaks. Chafe is the biggest enemy!!

One facet that has not been brought up: if you are using a rope with a too large diameter, you lose some of the stretch, and stretch is good, the longer the line and the thinner the more stretch. As you said you had nylon, and that stretches nicely. BTW nylon is nearly twice as strong as polyethylene or polypropylene, so in theory one could use smaller diameter when using nylon, so in your case 5/8 is more than adequate.

One last topic, you said you had 'nylon double braid'. Just a caution, many people cannot distinguish between nylon and polyester, particular in braided ropes. Both sink, unlike polyethylene and polypropylene that float.

BTW I use nylon 3 strand rope for my permanent docklines and braided line with a polyester mantle and nylon core for my 'travelling' docklines.

Will anyone shoot me for me using the word 'rope' twice ?

[nathan007]

Good thinking!