Failed Dockline

Thanks, Dave, that's very interesting. I will probably never climb with ropes, but I like to learn about things (and especially when this came up here as a boating topic).
 
A bit scary returning to find your dock lines broke! I am upgrading our lines to half inch from the 3/8'' that the dealer prepped the boat with.

Last summer we were tied to a wall near a lock. Left the boat for the afternoon - when we returned a good portion of the boats weight was hanging by the 3 dock lines! The power station in the adjacent channel had ramped up production - lowering the water level in our channel by over a foot.

On a smaller boat like ours I find the stern line the most vulnerable. At most lock walls it must go up over a rough concrete corner to the cleat. One place it was very windy/rough - I watched the stern line(3/8") fray almost half way through in about a half hour. Another spot the boat was hobby horsing from boat wakes funneling into the channel. The stern would go up and when it came down the stern line would snap taught. I found the way to remedy this was to leave the dockside stern line loose and bring a second line from the opposing stern cleat to the dock cleat. I found you can keep this line fairly tight to keep the stern close for stepping on and off but it lets the stern rise and fall without severely stressing the line. I also use chaffing gear on any lines that will rub on a concrete wall.

A good idea to bring the leftover dock line back to the boat cleat. Thanks.

Overnighting or leaving the boat unattended I always tie at least 3 lines.

Regards, Rob
 
We usually have two spring lines, as well as bow and stern lines. We try and not have any fine "short", and chafing gear (clear tubing) if necessary in area of chafe. We have both 3/8 and 1/2? dock line.

I have seen kids untie boat's dock lines (also seen anchor lines cut in several areas, both in the US and in Central America).
 
thataway":1sgkky4r said:
I use both braided and 3 strand. Splices are far easier to verify with 3 strand, and the elasticity is better with 3 strand.

I second the advice to learn to do your own 3 strand splices. Easy to do, and a skill you can pass on to others.

Also with a braid splice, I sew thru the tail of the splice, and that is an extra security.


When I was in the Navy I had to splice two lines together, then do an eye splice, followed by a back splice, with 3-strand as part of my seamanship test. I had 30 mins to do all three. You either passed or you failed, nothing in between.
It is real easy (not the 30 min part) and everyone should give it a try.

Martin.
 
I went down the road with commercial dock lines in short is that they suck. I will not spend another dime on that chintzy garbage. They fall apart after just one or two seasons. Meanwhile the static line has lasted at least 7 seasons. That's the math..... Seven years plus or two years. I know this will send some readers scouring the internet to attempt to change my mind but it will not. The static climbing ropes are just way more durable ropes than a dock line. I really love my boat and want to find it when I come back to the dock........Hence the best rope I can find keeps the old girl in place. Works very well so far and has shown longevity in service life.

Lots of choices in this world this is just one of many.

:smiled
 
One caution, and Chris's post made me think about it. That is there are a number of dock lines sold by places like WalMart, and sporting good stores which are of vastly inferior grade. It is very possible that Chris had one of these lines. There is a reason to stick with New England Ropes, Sampson or Yale Cordage! Several of the dock lines I have on the current C Dory are over 10 years old, and still in excellent condition.

I had 300 feet of 3/8" Sampson Brad which I used for over 30 years, in all sorts of applications, from primary anchor rode to lunch hooks on the latest boats I owned. I gave it away with one of the boats, when I was getting out of the big boat business. I have had dock lines last many years--but most of my boats were much larger than the C Dory and were in slips in marinas, where one had at least 2 bow, 2 stern and a couple of spring lines.
 
I've had good experience with Top Knot lines. Note how the loops are sewn, not spliced, so I would think it easy to see any impending failure. But in years of use I've never had a failure.
 
I hate being a "spoiler" here, but the Top Knot dock lines are solid braid polypropylene. Polypropylene is not resistant to ultraviolet. When exposed to sunlight, it quickly degrades from the ultraviolet radiation. The result is considerable weakening of the rope along with surface oxidation.
It has poor resistance to fatigue, has very little elasticity, and it is subject to internal friction under heavy load, and because of its very low melting point has been known to fail due to internal heat generation.

This is an example of what I would consider a very poor dock line. Yes, it floats--and can be made very cheaply. The Top Knot web site shows the spices with a heat shrink tubing--and it certainly may be sewn--but I would put it at the very bottom of what I want in dock or anchor lines! Sorry.
 
The Top Knot lines I have do not use heat shrink tubing for the splices but are fabric and have a quality feel. I sent a query to the company asking about some of the issues you raised and this was their response:

thank you for your inquiry to Top Knot, we have been providing American Made solid braid polypropylene to the marine industry for the past 20 years. We provide oem products to over 40 boat manufactures, as well as the Coast Guard, and law enforcement agencies all over the country. Our reputation speaks for itself. Our products are UV resistant, and provide excellent service. Your concern of breaking down over time, is an open ended question. All lines regardless of manufacturer, should be rotated out of service, after several years wear. Some sooner than later, depending on usability and conditions. Our solid braided construction, not only allows the lines to float, but do not contain any cotton in the center, which tend to rot and mold from within. They remain soft and supple. We have repeat customers that say our lines preform as well or better than lines made of other products

I understand opinions - like anchors - may vary but my experience has been good and I would buy from them again.
 
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