dock lines: tight or loose?

[rmeador]

I'm new to the whole sailing thing and I'm not quite sure I've got the dock lines figured out. I have two spring lines, two stern lines (crossed; I'm parked stern-to), and a bow line. I do not have snubbers, though I'm considering getting some. Very few of the boats in my marina have snubbers.

I think the lines stretched some over the winter. The boat seemed to be moving around in the slip a lot more than it did in the fall. I didn't like the feeling of it slamming against the limit of one of the lines or smashing into a fender. I figured smaller movement = less force, so I tightened up the lines. Now the movement is somewhat better, but I get the impression it is unhappy. It makes a lot more creaking noises. I wonder if the tighter lines are putting more stress on the hull? Perhaps it's trying to heel in the wind (the plastic wrap is still on), and the lines/fenders won't let it?

How tight should dock lines be? How much motion in the slip is the right amount? Is it more stress on the hull/cleats to have it moving around or sitting still unable to move? Thanks.

[mdbee]

Floating dock? Tide range?

[rmeador]

It is a floating dock. I assume that nullifies the need to know the tide range, but the range is about 12' (according to my observations; officially I think it's about 9').

[SlowButSteady]

I keep mine just a tad loose. That way there isn't a constant tension/stress on the deck hardware, and when the boat does move around it can't get going very fast before the lines arrest its momentum. Dock lines should be a bit stretchy (e.g., three-strand nylon, or some-such) to minimize the shock-loading on them and the hardware, and snubbers will further help. Perhaps most importantly, dock lines should be hefty enough, and inspected often enough, to minimize the chance of failure.

[rmeador]

Thanks for the info. I think "a tad loose" describes the situation I left the boat in this morning... I loosened up the bow line about 6" from the tight position it was in last night that was causing the creaking. I didn't stick around to see if it stopped creaking, but it seemed better. My dock lines are 3/4" double braid nylon, AFAICT. I have chafe guards on them at the places where they chafe, and I inspect them regularly.

[Boasun]

I keep mine tight. Have seen mooring line wear away due to chafe at the chocks and the bitts, because the constance sliding and stretching in those areas. Also I double up the lines if the vessel is going to be there more than a day. With the lines doubled you much less wear on them as a whole.
Bow and stern lines goes out at an angle from the boat, The forward spring line led aft to the pier and the after spring line led forward to the pier. Breast lines? I don't like them and won't use them, unless there is a strong wind blowing my vessel off the pier. One reason I don't like them is that they have to be continuously tended. Or you find you boat hanging from them as the tide goes out.
pier face where there is tidal action.... I will put a bight of my mooring lines around the pilings and this will allow the lines to slid up and down as the tide does its thing.

[Faster]

Using proper nylon mooring/dock lines will go a long way to softening the 'fetch-up' when pulling up short if the boat moves. It will also minimize the annoying 'gronk' heard throughout the boat when that happens.

My major concern with the 'tight line' scenario is that you typically will accelerate fender rub, leaving flat spots on the hull finish (at least) and possibly grinding grit and dirt into the hull that way if the moorage environment is not pristine.

We leave our boat free to move about some; if the slip is tight with another vessel then a relatively softly-inflated fender(s) between them will ensure no serious contact is made as a result.

[CapnBilll]

Mine is on a fixed pier. We can have a 3-5' sudden drop in the winter. So I have to keep my lines very loose. I leave just enough slack so the boat cannot colide with something bad. I have come during the winter to see it resting on the bottom, the dock lines fully stretched. In the summer when the tides are higher I tighten them leaving just a little slack, (about 3' for tidal range 1' + or - with 1 ' slack left over). With floating piers you can keep them tighter all the time. I hope this helps. Use wide angles to maximize vertical movement with out long dragging loops, (that is why we cross at stern).

[L124C]

I keep my lines loose to let her move. In high winds when the stick, and therefore the keel, is getting blown around, I want them to be able to dance as designed, not be bound by tight lines. 4000 pounds (in my case) under the water line tends to act like it's own snubber, dampening the action if you let it. I think tight lines are hard on the boat, lines and dock. I can't address locations where excessive surge exists, as I've never berthed a boat under those conditions for any length of time (and hope I never do!). I highly recommend mounting fenders to the dock instead of hanging them off the boat for various reasons. Search for my thread on the issue if interested.

[casey1999]

Here in Hawaii, in the winter we get what they call surf beat. It is the high surf basically ground swell coming into the harbor. It can really move my 34 footer around with it 6 foot deep keel. Since I cannot center the boat (we are in I guess what you call a double slip) I need to tie her tight against the floating pier.

I use a lot of big fenders to cusion the blows. I also use the west marine shock snubbers at all dock lines. I use the rubber type that you wrap the dock line around (more times around, greater shock capacity). The snubbers I think are great. I use 3/4 inch double braded line and have no wear problems. The snubbers really take the shock off my deck cleats. In our harbor many boats break cleats or mooring lines when the big surf rolls in. For chaf guard I take the nylon tubing (west marine sells the stuff) and run my dock line through it. The nylon tubing is not advertised for chaf guard but it is somthing like fire hose and much cheaper than real chaf guard. The tubing will wear before the expensive dock lines and if you rotate it around a little from time to time it wears more even. In winter I also double up on my lines tying the back-ups (without snubbers) much looser and not doing anything unless main line breaks.

I am kinda paranoid about my boat breaking loose and getting damaged.