watson524

How much stretch in lines to account for

6 posts in this topic

The new boat is going into our single slip today. We have fenders on the dock on the front corners, 3 across the back at the main walkway (we'll be stern in) and so far 1 on each side. We will add 2 more on each side once we see where the boat sits in the slip.

We have no tides and generally no wake to deal with since we're so far into the no wake zone on the lake. 

We have 4 cleats on each side of the boat. We intend to cross lines in the back from the swim platform cleats, then have them from the bow cleats to the 2 uprights at the end of the fingers. May need to move them back a cleat if having them on the bow would have the lines pointing back and not offering any stoppage from moving forward. Then I intend to have at least one spring line on each side from the upright posts at the end to a midship cleat that'll be used when backing in to help stop motion. So the question is...

In general, how "stretchy" are nylon 1/2" lines? I want the boat sitting as far back in the slip as possible without constantly rubbing those 3 rear fenders on the dock so I assume I should leave the spring lines a bit short but not sure how short or if it matters and you just tie it for calm water?

On the old boat is was bow in with a line from each upright in the back to the hooks on the transom and a single line with an eye hook in the middle that went to the bow eye and then to each upright at the front and fenders all around.

thanks in advance!

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Scientifically, West Marine says 6.5% stretch at 20% of breaking load on their 1/2 inch nylon dock lines.  Breaking load for their 1/2 inch dock lines is 8000 lbs with a 28.5% stretch at breaking point (I just bought new dock lines the other day, remember seeing they had specs in their description to looked them up again quick).

I think you would be safe to assume 15% at worse case, more likely 10% would be fine.

Another option, although more expensive (a lot more) but when you have such a nice boat it might be worth looking in to, is a lift (Hydro Hoist, etc).

 

 

 

 

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Thanks for the info. As for the lift I've looked but unfortunately tho the power company owns our lake there's no shore power allowed. Plus the dock owners wouldn't allow even a battery or solar powered lift (docks owned by power company at our marina) and I even looked into the drive on kind but no dice within the slip size for our size boat. I'd love a lift! 

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I never account for stretch in my lines.  I just set it where I want and it stays all season.  I use a spring line to keep it from rubbing on the fenders at the back of the slip and I criss cross my stern lines.  I'm in a double slip.  I have fleece covered dock bumpers on my dock and a corner pad.

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Thanks for the info. I think we got it sorted ok tho honestly, I could stand some shorter lines vs the 15' and 25' we had but it's in the slip (another post coming on that) and secured with lines crossed in the back, lines from front cleats back to uprights on dock and mid-cleats forward to uprights on dock and 3 fenders on each side including the back plus one on each of the front corners of the dock (single slip).

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