Dock Line Tension

[billdre]

So here I am in my slip for the holiday weekend. A little too blustery to be out on the water. I notice that the power boats docked around me are hardly moving at all. My sailboat is floating lazily on its lines, back and forth, up and down. I go look at the power boat next to me and realize his lines are tight on all quarters. They are holding his boat almost rigidly in place. Important note, these are floating docks. No need to worry about tidal action. I have always left my lines with a little slack in them. Never thought about tightening them up at all points. Have I missed something? I wonder if it makes any difference to chafe? My lines only get "tugged" now and then, the tight ones run solidly over the edge rails rubbing all the time. Any thoughts or best practices??

[belizesailor]

Even with floating docks I prefer a bit of slack in mine, but not really necessary on floating docks.

[delmarrey]

I've always tightened mine up as tight as I can get them for a standard tidal dock. BUT, it may depend on the dock and marina themselves.

I've been in some places that it doesn't really matter. The docks are so loose or light weight, that all tightening does is lift the dock.

But anytime a line is allowed to go loose and then tight again 24/7 it will eventually start to chaff, let alone the constant SHOCK it puts on cleats and their fasteners.

Also you'll want to use nylon lines unless they are fairly long. Anytime I'm in a place with a lot of wave action I use rubber snubber. Another thing is to rotate your lines occasionally to keep from wearing the same spot on the line, or add a chaff guard.

[Mystic38]

imo this is the reverse of what happens...

when a line is tight..any movement of the boat due to wind, waves, foot traffic whatever, goes DIRECTLY to the cleats and to the boat.

looser lines allow the boat to move naturally and so be a shock absorber for any movement.

Loose lines in no way shape or form directly translate to increased chafe... given that the boat is not straining against the lines then there is less suddent transient load on the lines and therefore less wear.

Originally Posted by delmarrey

I've always tightened mine up as tight as I can get them for a standard tidal dock. BUT, it may depend on the dock and marina themselves.

I've been in some places that it doesn't really matter. The docks are so loose or light weight, that all tightening does is lift the dock.

But anytime a line is allowed to go loose and then tight again 24/7 it will eventually start to chaff, let alone the constant SHOCK it puts on cleats and their fasteners.

Also you'll want to use nylon lines unless they are fairly long. Anytime I'm in a place with a lot of wave action I use rubber snubber. Another thing is to rotate your lines occasionally to keep from wearing the same spot on the line, or add a chaff guard.

[model 10]

I'm of the lots of them and kinda loose school. I like to see the boat moving around a little, among all the lines.

[roverhi]

On a floating dock, leave the fore and aft lines a bit loose. Snug up the spring lines, however. Don't want the boat surging fore and aft but dancing around on the bow and stern lines takes a load off the cleats, both on the dock and boat, and cuts down on chafe at the chocks.

Why are you looking at power boats for guidance?? Them stinkpottere don't know nuthin.

[Cruisingscotts]

Bone tight dock lines do as described above, they send all the load to the dock or boat, which is bad. Your lines should have some elesticity to absorb shock loads. The rubber things are a personal prefrence and tread into the "how to anchor territory". Spring lines keep your boat moving fwd and aft, brest lines keep it from moving away from the dock. Its good practice to try and tie your boat up with relatively even tension, not too tight on all lines and situate so that in any scenerio at least two lines will be loaded evenly. For example a fore and aft midship spring and fore bow and aft stern. You can snug things up when you are on and off the boat to keep it tight to the dock and if leaving for a bit let it out some.

[delmarrey]

Obviously some of you have never been to sea in heavy weather.

While in the Navy going thru typhoons it was policy to tie everything down as tight as it could get with turn buckles and cables or chain. It's common knowledge that once something starts in motion it just gets worse over time. Try tying a fork truck down once it's worked loose. Or watch a 400# barrel start rolling around in high seas. The same applies to truckers hauling heavy equipment.

Just think of a slide hammer attached to your cleat, or your shrouds loose on your mast.

[a64pilot]

I leave mine tight, always have, but do see many who leave them excessively loose, and some just a little loose.
If you leave them tight, be sure you can get back to the boat for any kind of storm, to loosen them as need be for storm surge.


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[FSMike]

Originally Posted by delmarrey

Obviously some of you have never been to sea in heavy weather.

While in the Navy going thru typhoons it was policy to tie everything down as tight as it could get with turn buckles and cables or chain. It's common knowledge that once something starts in motion it just gets worse over time. Try tying a fork truck down once it's worked loose. Or watch a 400# barrel start rolling around in high seas. The same applies to truckers hauling heavy equipment.
-----

Interesting. What is the navy policy as regards small craft, say less than 50', which aren't normally tied up with anything other than rope?

[model 10]

[QUOTE=delmarrey;2158721]Obviously some of you have never been to sea in heavy weather.

What kind of BS is that? You are not at sea when you are using dock lines.

[markpierce]

To avoid squeaks, I place a slight amount of slack on the lines, except of course where wind/tide is tugging.

[El Pinguino]

I always use nylon dock lines , tight as I can get them by hand, which means they are still a bit slack if you get my drift....

[thinwater]

I put a load cell on them this spring, both tight an loose. While there are many variables, you'll find the loads are about the same either way. Various damping effects due to the hull moving through the water and gusts being out of phase with impacts are apparently off-setting./waves

With tight lines the snubs are more frequent but cause little line movement. With loose lines the snubs are less frequent but involve more motion and rubbing.

I'm not going to say which is better.

[Cruisingscotts]

Originally Posted by delmarrey

Obviously some of you have never been to sea in heavy weather.

While in the Navy going thru typhoons it was policy to tie everything down as tight as it could get with turn buckles and cables or chain. It's common knowledge that once something starts in motion it just gets worse over time. Try tying a fork truck down once it's worked loose. Or watch a 400# barrel start rolling around in high seas. The same applies to truckers hauling heavy equipment.

Just think of a slide hammer attached to your cleat, or your shrouds loose on your mast.

I don't think the OP was planning on a typhoon hitting his Oday 27 in Boston anytime soon, rather asking why people do or don't tie there boats tight..........

Yes at sea things need to be secured so the vessel and all its bits move as one. Tying your boat up for a hurrican or typhoon would be a little different than the ocasional winter gale, but the same applies, the dock doesn't move and if your boat is made fast to it with no elsticity in the attachment IE mooring lines all load goes directly to the harware on the dock and boat.