New Dock Lines

In another thread I talked about trying a new system for my dock lines at my home slip. The 3/4" three strand that were there were started to get very chaffed, partly because I had to put two lines on the same cleat a couple places and the cleats aren't really sized for that.


It also meant a lot of line on the dock. I tried to keep it neat but the line just collects dirt.


So that was what I didn't like. I decided to try something different. I did get the eBay 5/8" nylon three strand. 600' for $250. I figured even if it was cheap and didn't wear well, I could just make up new lines.

I also got some 2" wide climbing spec tubular webbing to use as chafe protection on the boat side. 1 1/2" would have been better for the spliced eyes, but it was expensive. I got 150' of the 2" for $100.

I bought some nylon 5/8" thimbles from Defender. I don't recall how much they cost, but at least those I can reuse.

Finally, I made up dyneema soft shackles. I already had the dyneema but making up these and the continuous loops I made for my anchor had just about depleted my 3/16" dyneema. I had had it for a number of years, using it for my sailboat. I ordered some more just to have it, $30 for 50'. That will last me another 10 years.

So, $400 in materials. Yes, I KNOW I COULD HAVE BOUGHT DOCKLINES FROM WM FOR LESS. However, I have enough material to make dock lines for years, not to mention anchor bridles, snubber etc... Besides, I think my system will end up being better.

OK, this is how I made them.

I spliced an 18" eye in the 5/8" three strand. Before splicing it, I put a 37" length of the nylon tubing on the eye to give me some added chafe protection. That webbing is also really nice on the hands. An unexpected bonus.

The eBay 5/8' three strand, as HopCar surmised, isn't as high a quality as rope you would buy from NER or Sampson. As HopCar described it, each of the three strands was likely not heat set. This means that it is a bit more difficult to splice. I've spliced this type of rope before and it works fine, you just have to control it more carefully while splicing. As is always the case, my splices got better as I went along. The fingers recalling the muscle memory.

Once the eye splice was on, I used whipping and sailmakers palm to stitch the webbing in place at the base of the eye. I didn't want the webbing to move along the eye. One reason I made the webbing 37" for an 18" eye was to allow the three strand to stretch without putting stress on the stitching. I did the eye splices at home over a couple evenings watching the comedy that is the Trump Administration on the news.

Today, I took it all down to the boat to finish it up. The idea is to use the eye splice on the boat side, and a thimble and soft shackle dock side. I needed to be sure that the lengths were correct. I first made sure the boat was tied exactly in the position I wanted, then made each new line one at a time. I would put the eye over the cleat on the boat, and make up the thimble temporarily with a constrictor knot. I would adjust it until line was tight enough but gave me just enough slack to get the eye off the cleat.

Before splicing the thimble I put a 8" length of tubular webbing not the line which I later stitched in place over the splice on the eye end. I overlapped the webbing and it actually looks pretty good. Added chafe protection but really entirely unnecessary. I just wanted to see if it would work. When all that was done, this is how each looked.


Add a soft shackle


And this is how it looks.


I still have one more line to finish. The weather was nice and I was sitting in the cockpit splicing away and finally decided to go for a sail. So I will finish the other one later in the weekend. So far with they 5 lines that are replaced, it seems to be working great.

Looks great.
It is rather funny looking at the dock cleats and seeing the dyneema securing the 3 strand to the cleat. I'd love to hear the comments from the uneducated dock walker.

What about occasional adjustments for abnormally high or low tides?

FWIW, we pre-measure our home lines, too... although we run line through use the original eye for the pile end, and then I just make a loop on the boat end with a bowline -- at the appropriate normal length. We still have to futz with the lines occasionally even though our normal tidal range is only 18"-2' or so...

-Chris

Oddly enough, unless you look at them specifically they happen to look a lot like galvanized shackles. Part of that is because I like to leave a little tail on my stopper knots.

I do that for two reasons. The first is that under really high load the tails will get sucked into the knot a tiny bit as it tightens up. I have not bothered to setup a jig to tighten the stoppers. So having a short tail provides an added bit of security. To be honest, on the sailboat I have never seen this happened regardless of the load.

The second reason is that I have found a soft tail makes it just a bit quicker and easier to insert the knot through the shackle.

Btw, testing of the soft shackle similar to what I make show a breaking strength of >6,000 lbs. If I used a different stopper knot (the button knot), I could get another 2,000 lbs strength out of it. However, the button knot is a lot more complicated to tie with more chance of error. I can tie the diamond knot in my sleep so am happy with that. If I decide that I want to have over 8,000 lbs breaking strength I'll just move up to a 1/4" dyneema rope.

ranger42c said:

What about occasional adjustments for abnormally high or low tides?

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Pretty much all marinas are floating docks in PNW, BC, and Alaska. No need to adjust.

Northern Spy said:

Pretty much all marinas are floating docks in PNW, BC, and Alaska. No need to adjust.

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Yup, I can't recall ever docking at a pier, always floating docks. While it makes dock more expensive in some ways, it does make it very easy to just keep you home dock lines constant.

It has gotten me thinking about some type of adjustable length shackle. It wouldn't be nearly as strong, but might be strong enough to use for the dock lines.

Dave-- I like your shackles and rope eyes idea. Might try copying your idea this season.

So at 2AM some guy walking home notices the boat on fire next to yours. How does he quickly cast off your lines?

With a knife. I always carry one.

Acheron/Comodave
A fire next door, or where near your boat take a walk, or run. You will never have time to dedock under such conditions. Chaos prevails and insurance will be the route. The best way to fight a fire whilst underway is your dingy.

Cyclone said:

Acheron/Comodave
A fire next door, or where near your boat take a walk, or run. You will never have time to dedock under such conditions. Chaos prevails and insurance will be the route. The best way to fight a fire whilst underway is your dingy.

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I have been involved with several marina fires and overflew many more coordinating response from various agencies.

I would say most of them, I could have moved several boats before it became dangerous to do so.

One, I towed the burning boat out of the marina away from the fuel dock.

Being able to move the two adjacent vessels from a burning boat can be invaluable in saving many more.

But then again for 35 years I assessed and took those kinds of risks as a pro.

Acheron2010 said:

So at 2AM some guy walking home notices the boat on fire next to yours. How does he quickly cast off your lines?

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Lift the fenders, pull some slack into the lines, feed the knot through the soft shackle, yer done.

Acheron2010 said:

So at 2AM some guy walking home notices the boat on fire next to yours. How does he quickly cast off your lines?

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From the boat. Cast loose the eyes around the cleats and hawse holes. Or a knife of course. It is easy to undo the soft shackle but I imagine most won't have a clue on how to do it.

OK, the idea of an adjustable line got me thinking. The lines as they were worked great, but maybe just a tad bit of extra slack. I want the slack so the eyes are easy to take off and put on the cleats. Still I was wondering....

If I had one line that was adjustable, it would take up the slack on the others and keep the boat from moving quite as much. So, I came up with an adjustable line. It seems to hold really well and a bit of research tells me that it has about 80% of the breaking strength of the line uses (according to Sampson ropes anyway). That is over 4,000 lbs. Of course the way I have it setup, it is a 2:1 pulley so that is 4000lbs on one leg. The total system then would be 8000 lbs which is greater than the soft shackle. Not sure if that works out right, but it plenty strong enough for my purpose here. I used it on an aft breast line on the port side. I am starboard tied to the dock.

Here is the adjustable line. Two loops, one fixed and the other adjustable. It adjusts by pulling the tale to make the loop smaller and then a quick milk of the cover over the buried portion. To expand it, you simply take a little of the load off (pull the boat in a bit) and then pull on the buried tale from the loop side.



I have both the fixed and adjustable ends shackled to the cleat with a soft shackle. The line runs through an eye with a thimble in the 5/8" line that had the spliced eye on the boat.

Here it in setup on the boat and dock with it almost as long as it will go. I have marked the near and distal ends of the loop so you can see its length.


Here it is after being tightened up.

Distal ?. My wife's an OR nurse, and my friends are physicians, so I understood what you were talking about.

FWIW, what you built is (un) commonly known as a whoopie sling.

Northern Spy said:

Distal ?. My wife's an OR nurse, and my friends are physicians, so I understood what you were talking about.

FWIW, what you built is (un) commonly known as a whoopie sling.

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Yup. Sounds slightly naughty somehow...

A fire? NO WAY is anybody going to quickly move my boat. The boat is located between 4 pilings two on each side and backed into the dock. There are 2 bow lines, 4 spring lines, 4 lines tied to stern, two power cords and finally one water hose.

Wait. 2" webbing is cheaper than 1 1/2"?

Not to be negative, but it looks like quite a few potential wear/failure points. Loops upon loops look like many wear points waiting to happen.

I'd prefer a single line wrapped around a shock absorbing rubber snubber, if needed. In my way of thinking, lines on cleats should get wrapped with the main line and not tied on. You never know when someone needs to release your lines for the safety of others. I'd like mine to be able to release without the need for study or special tools.

High Wire said:

Wait. 2" webbing is cheaper than 1 1/2"?

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2" seems to be more common. I was able to get a roll for about $0.66/ft.

FlyWright said:

Not to be negative, but it looks like quite a few potential wear/failure points. Loops upon loops look like many wear points waiting to happen.

I'd prefer a single line wrapped around a shock absorbing rubber snubber, if needed. In my way of thinking, lines on cleats should get wrapped with the main line and not tied on. You never know when someone needs to release your lines for the safety of others. I'd like mine to be able to release without the need for study or special tools.

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Yup, I understand your idea about wear points. However.... I have had chafe three places with my current lines. Where the eye is over the cleats on the boats, where the lines are cleated to the dock, and a couple places where the line rubs against the boat. The biggest source of chafe was at the dock cleats. My lines needed to be replaced because of that.

Now with the new system there are still the same sources of contact however I have one additional point, where the soft shackle connects to the nylon thimble. However, that is an extremely low chafe contact since the nylon thimble is so smooth.

The dyneema is more resistant to chafe than the one nylon three strand was. Plus, I have some dyneema covers coming that I will put around those shackles which will reduce the chance of chafe even more.

I think the nylon lines will last indefinitely with the current configuration. They won't wear at the thimble and with the nylon webbing cover, the chafe at the boat cleats will be minimal. If the soft shackles chafe, I can replace them. Each of the shackles costs me under $2.00 and 10 minutes to make.

As for the safety issue, I just don't see it. Sure there are marina fires. I can recall two in my area. Never have any of my boats needed to be moved by others in an emergency. So, just as I don't leave the keys in my car at the market parking lot in case someone needs to move it in a hurry, I am not going to worry to much about making sure someone else can easily move my boat in an emergency.

Update:

This is an old thread but today I had the boat hauled and since it is going to be out of the water all week, I decided to do something about the dock lines I installed over 4 years ago. These lines have been in place, on the dock, that whole time.

Being in the PNW, the white dock lines are now a lovely shade of green. For some reason, my wife isn’t happy with that. So I brought them home to clean and/or replace.

There was a lot of discussion about my use of soft shackles to connect the thimble on the dock line to the base of the cleat. One of the concerns is how they would hold up to extended use in the sun and chafing. My initial thought was to use a dyneema sleeve around the shackles at a chafe preventer. I ended up instead using some nylon tube webbing.

The webbing is now very old and tired but it did a good job of preventing chafe of the shackle body it covered. There were a few places when the tubbing didn’t fully cover and the shackle did rub against the galvanized cleat. I have photos of the worst.

The shackles themselves held up really well. I’ll retire them now, but to be honest I think they all would still be good for another 4 years. The nylon lines themselves, with the spliced loop boat side covered with a nylon webbing and the thimble through the soft shackle are in perfect shape other than being unsightly.

Great follow up. Thanks Dave!

Completely get the green mooring line comment too. Bugs me as well.

I also make Dyneema soft shackles for connecting my bridle to my anchor chain. Dyneema is a very strong, UV resistant tool to have on a boat. I make the shackles with a button knot, to ensure this single point of failure does no fail. Probably overkill, but I could easily add a 2nd redundant soft shackle to my bridle set up.

Dani lu said:

I also make Dyneema soft shackles for connecting my bridle to my anchor chain. Dyneema is a very strong, UV resistant tool to have on a boat. I make the shackles with a button knot, to ensure this single point of failure does no fail. Probably overkill, but I could easily add a 2nd redundant soft shackle to my bridle set up.

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Yeah, i use the button knot as well. I agree that it likely overkill, but since I can, why knot? After I haven’t made one in a while, it takes me a bit longer to do the first one. I made up two the other night. Probably 20 minutes to do the first, under 10 to do the second.

Dani, you may be interested in this use of some modified shackles for my anchor bridle.

https://www.trawlerforum.com/forums/showpost.php?p=795096&postcount=107