Single line to serve as fore and aft spring line in slip

[67Therapy]

Home marina slip...fairly protected...1.5' tide range...pilings and floating dock...~30K disp...3/4" 3-strand nylon

1. What about using a single line from piling to boat cleat to floating dock cleat that would serve as both the forward and aft spring lines?
1a. Could you put a loop in the middle of the line to attach to the boat cleat...easy on/off when heading out and returning. How would you make the loop?

Pro: Easy
Con: a loop w/knot would reduce the line strength...by half?
Con: a line failure could leave you without either spring I suppose

I've seen boats do this in different marinas and wanted to pick the collective brains here to see what folks thought...here to learn. Thanks

[roverhi]

Did this with a line long enough and a cleat big enough to belay for tension both fore and aft. You could do a brummel splice to get a loop in the center if you went that route. The problem with a loop is that there will be some inevitable slack in the line. With only a 1.5' tidal excursion and floating dock, may not be a problem.


Wouldn't worry about a knot reducing strength of the rope. Unless you have a 15 ton boat, 3/4" inch is overkill for strength. It's chafe that does in most mooring lines.

[Rakuflames]

Originally Posted by 67Therapy

Home marina slip...fairly protected...1.5' tide range...pilings and floating dock...~30K disp...3/4" 3-strand nylon

1. What about using a single line from piling to boat cleat to floating dock cleat that would serve as both the forward and aft spring lines?
1a. Could you put a loop in the middle of the line to attach to the boat cleat...easy on/off when heading out and returning. How would you make the loop?

Pro: Easy
Con: a loop w/knot would reduce the line strength...by half?
Con: a line failure could leave you without either spring I suppose

I've seen boats do this in different marinas and wanted to pick the collective brains here to see what folks thought...here to learn. Thanks

I use such a line, carefully set up, for easy "one click" docking. Then I don't have people jumping off my moving dock because they're so sure I need them to do that or the boat will crash or something, and I can also dock the boat by myself. But I have standard spring lines on the other side, and I use standard spring lines read .on both sides during hurricane season.

I call it a 'double ended spring line,' and I have a carabiner in a figure 8 loop. I have the place it goes on my toe rail marked with a zip tie.

The hardest thing about it is convincing people new to my boat that they don't have to do anything. I drives them nuts.

[FSMike]

Originally Posted by 67Therapy

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1. What about using a single line from piling to boat cleat to floating dock cleat that would serve as both the forward and aft spring lines?
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I'm not sure about two points of the line floating and one point fixed.
If you try it keep an eye on it through the tide changes.

[bobconnie]

Ive always thought of spring lines as the most important line I have aboard! I use them to dock and un-dock my boats, they must be controlable quickly, as they have a very important duty to control movement during wind changes of direction, or when the wind speed raises in speed. I prefer to control my lines from the deck rather then the dock. So there for I would not use one line with a loop as spring lines ! Again theres different strokes for different sailors, and all that, but I learned to sail a boat in an area that had daily 8 to 11 ft tides, and the abilty to use your spring lines made it the only way you could get a boat to and away from docks with ease and safety! I don't know how many folks on here have asked how to get their boats away from there docks in wind and tide conditions, never saw anyone say to add a loop in the middle of their dpring line to help with this action ! LOL Sounds like a good idea at first, at least till ya think about the other uses of spring lines besides being tied to a dock. just my 2 cents

[Andrew Troup]

The Alpine butterfly knot is a pretty strong way of adding a loop in the middle of a line, used by climbers, not to mention linesmen for the county who are still on the line...

A figure 8 loop is good, too, and easier to remember, but becomes difficult to untie if that's a consideration.

[Rakuflames]

Originally Posted by FSMike

I'm not sure about two points of the line floating and one point fixed.
If you try it keep an eye on it through the tide changes.

if they're tied to a floating dock, all three points will stay together.

We don't have extreme tides here so it works fine, except, as I said, for tropical storms and hurricanes, where we can have extreme tides even without a direct hit.

[Rakuflames]

Originally Posted by bobconnie

Ive always thought of spring lines as the most important line I have aboard! I use them to dock and un-dock my boats, they must be controlable quickly, as they have a very important duty to control movement during wind changes of direction, or when the wind speed raises in speed. I prefer to control my lines from the deck rather then the dock. So there for I would not use one line with a loop as spring lines ! Again theres different strokes for different sailors, and all that, but I learned to sail a boat in an area that had daily 8 to 11 ft tides, and the abilty to use your spring lines made it the only way you could get a boat to and away from docks with ease and safety! I don't know how many folks on here have asked how to get their boats away from there docks in wind and tide conditions, never saw anyone say to add a loop in the middle of their dpring line to help with this action ! LOL Sounds like a good idea at first, at least till ya think about the other uses of spring lines besides being tied to a dock. just my 2 cents

Depends on where you are, I guess. I've used them for nearly 2 1/2 years, *except* during tropical storms.

I wouldn't be without it, but it's very easy to allow for the tides we have here.

[Stu Jackson]

If you have a line doubled like that, it seems to me that you almost always will have to be on the dock at one time to undo one end while the other is still connected to the dock and the boat. For that reason alone, and 'cuz i fully agree with bob, I doubt it's a good idea. Each line should have its own use, and a forward spring line is not the same as an aft midship spring line. Good luck.

[Wotname]

Originally Posted by 67Therapy

Home marina slip...fairly protected...1.5' tide range...pilings and floating dock...~30K disp...3/4" 3-strand nylon

1. What about using a single line from piling to boat cleat to floating dock cleat that would serve as both the forward and aft spring lines?
1a. Could you put a loop in the middle of the line to attach to the boat cleat...easy on/off when heading out and returning. How would you make the loop?

Pro: Easy
Con: a loop w/knot would reduce the line strength...by half?
Con: a line failure could leave you without either spring I suppose

I've seen boats do this in different marinas and wanted to pick the collective brains here to see what folks thought...here to learn. Thanks

Presumably you are planning to leave the spring line attached to the piling and dock while you are out sailing. If so, then the idea has some merit. Both ends of the line remain attached to permanent points while you are away and it is easy to pick up the line when you return.

For a variety of reasons I prefer to take all lines with me with I leave; even if only for a few hours. In this circumstance, a single line has a few drawbacks.

As others suggest, chafe is more of a concern than knot strength. If your lines are sized for significant chafe wear then the strength reduction by the knot will be inconsequential.

[67Therapy]

Originally Posted by roverhi

With only a 1.5' tidal excursion and floating dock, may not be a problem.

Yes, I would have to make the loop/knot such that it wouldn't slip over the cleat easily.

Originally Posted by Rakuflames

I call it a 'double ended spring line,' and I have a carabiner in a figure 8 loop. I have the place it goes on my toe rail marked with a zip tie.

I can't do the carabiner thing since I don't have a toe rail like that, but you've got the idea I have.

Originally Posted by FSMike

I'm not sure about two points of the line floating and one point fixed.
If you try it keep an eye on it through the tide changes.

I know. I wish the whole marina floated, but as is, only the dock and small finger float...I back in, and the bow and forward springs attach to pilings that are fixed. The tidal range is small usually, so this is generally not an issue.

Originally Posted by bobconnie

LOL Sounds like a good idea at first, at least till ya think about the other uses of spring lines besides being tied to a dock. just my 2 cents

BandC, I don't want to discount anything you've said. When I'm pierside, the springs are very useful/helpful for how dock and get underway; In my slip however they seem to just be limited to constraining my fore/aft movement. I have a fin/spade configuration and a bow thruster...thusly my "real" seamanship skills are lacking with the BT "cheater"... I don't practice any springline maneuvers to get in/out of the slip.

Originally Posted by Andrew Troup

The Alpine butterfly knot is a pretty strong way of adding a loop in the middle of a line,

Excellent. Thanks for that advice.

Originally Posted by Rakuflames

as I said, for tropical storms and hurricanes, where we can have extreme tides even without a direct hit.

In the event of a storm, I intend to double up and lay out "real" spring lines...the "double spring line" as you named it would be my "day to day" set up.

Originally Posted by Stu Jackson

If you have a line doubled like that, it seems to me that you almost always will have to be on the dock at one time to undo one end while the other is still connected to the dock and the boat.

I just want to drop the loop from the boat cleat into the water leaving the piling and dock line connected. Actually, I would flake it over a taught line I run from piling to dock...Keeps it out of the water and makes it easy to pickup with the hook.

Originally Posted by Wotname

Presumably you are planning to leave the spring line attached to the piling and dock while you are out sailing. If so, then the idea has some merit. Both ends of the line remain attached to permanent points while you are away and it is easy to pick up the line when you return.

Yep, that's the plan. I'll ensure I rig for chafe.

All, this has been a great discussion...I appreciate the contributions! Learn more and more here everyday.

[ggray]

For the last 19 years, two different catamarans lying along a floating dock with no outboard piling, I have secured with "double" lines from both bow cleat and stern cleat. Serving as bow line, stern line and two spring lines. Also have two breast lines angled fore and aft.

For my "double" lines, I just double over each line at the appropriate place, and tie to cleat with normal hitch. I do work the line to make sure all parts are snug, but I've never had a problem. Yes, it is more difficult to adjust, but doing one at the time it is not bad.