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Old 04-29-2013
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Re: Forces on a dockline while docking....

Quote:
Originally Posted by SlowButSteady View Post
Docking rule #1: never approach the dock faster than you're willing to hit it.
I used to believe this, but that thinking got me in a lot of trouble.

If there is no wind or current, you should approach at dead slow or close to it. Anything more is asking for trouble that you don't need. However, if there IS wind and or current at play, you need to have more throttle (judiciously applied) in order to have more flow (or wash) over the rudder and thus more steerage.

If you're trying to come into a dock, even with 8-10knots of side-on wind and apply above rule #1 the wind will have it's way with you and you'll get to see the consequences of the second part of the rule. At least that's the case on my boat where the windage at the end of the bowspirt is 30-35ft forward of my underwater center of lateral resistance.

Now, I'm no Captain Ron either, charging full throttle into slips that I could approach slowly. My neighbor pulled the stunt I mentioned whereas I would have executed plan B or C. In fact, I have come at my old slip with a similar but less ferocious quartering wind and when I didn't like the way things were shaping up I aborted the landing and poached a side tie until the wind abated.

This technique is usually done at <3knots when I do it, and in the future (with kids occupying the wife) it will be the single-handed method of choice when docking. I just want to make sure that the loads are somewhere near reasonable and that the line (and cleats) are up to the job just in case I had to do it at a higher speed in some kind of emergency.

The fastest I've ever done this was probably 4knots and I used a 1/2" 3 strand line that was probably 20ft long. Nothing broke, nobody died, and it brought us to a halt when things were hairy.

MedSailor

PS I like the climbing rope idea. Perfect application for my line that is about to be retired. PDQ, what do you think, would this be a factor 3 fall?
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