Eye splice vs splice w/thimble vs direct splice vs soft shackle

[crayiii]

Firstly, I'm trying to learn the proper terminology but I'm sure I've messed up. I absolutely welcome corrections

I'm setting up a new bridle system on our cat that will utilize the stainless eyes on each bow as the attachment points. The factory bridle just has the lines looped through a spliced eye in the line through the stainless eyes.

The nice things about the way it's currently setup is it's really quiet since there is no metal to metal connection.

I'm trying to decide how I should connect the new line to the boat. I could do it the same way, use a shackle and splice a thimble into the line, splice directly to the eyes, or use soft shackles on the boat to attach the line that has a thimble spliced in.

Like I said, I know my terminology is not correct but I'm learning.😎

[Suijin]

I would put thimbles in the bridle splices and attach them to the padeyes on the boat with soft shackles. You could use nylon thimbles to reduce any noise of the thimbles contacting the hull in lulls, or make the soft shackles longer or both.

Dyneema is extremely chafe resistant in an application like this. The shackles should last a couple of years or longer.

[thinwater]

Originally Posted by crayiii

Firstly, I'm trying to learn the proper terminology but I'm sure I've messed up. I absolutely welcome corrections

I'm setting up a new bridle system on our cat that will utilize the stainless eyes on each bow as the attachment points. The factory bridle just has the lines looped through a spliced eye in the line through the stainless eyes.

The nice things about the way it's currently setup is it's really quiet since there is no metal to metal connection.

I'm trying to decide how I should connect the new line to the boat. I could do it the same way, use a shackle and splice a thimble into the line, splice directly to the eyes, or use soft shackles on the boat to attach the line that has a thimble spliced in.

Like I said, I know my terminology is not correct but I'm learning.😎

Pictures help.


I assume the eye was luggage tagged into the eye. This generally means no movement and no chafe. Thus no thimble is required. Stainless does not really chafe rope much. If you use a thimble it makes burs, after which there is no easy going back.


A soft shackle will probably be weaker, since the bearing surface will be less. I have done it that way for boat-specific reasons, but it probably won't help you.


Chafe gear, of course. Different boats need different solutions.Sail Delmarva: Anti-Chafe Gear


Remember that a bridle, like dock lines, is a wear item that should be replace every few years, not just because of wear and UV damamge, but because the nylon slowly becomes stiff and looses its ability to stretch.

[crayiii]

Here's a photo of what's on each bow. The large line is what we're using now until we sort this out. The smaller line is from the factory.

[Psy at SEA]

My question is why are you side loading that shackle (clearly not a mooring shackle) with tht brown cord ?

Secondly does that shackle face forward...... or to the inside (stbd)?

[crayiii]

Originally Posted by Psy at SEA

My question is why are you side loading that shackle (clearly not a mooring shackle) with tht brown cord ?

Secondly does that shackle face forward...... or to the inside (stbd)?

That's the bridle attachment Lagoon gives us. It came from the factory with the bridle attached there. It faces directly starboard.

[Psy at SEA]

i would replace the bridle as you have already decided to do and/or beef up the whole design ~ it appears that you have the twin arrangement stbd side. Sorry to say that area doesn't look much like a mooring point, but that's all you got so make do with it. Soft shackles are the stuff.

Good luck, keep floating.

[BobL1981]

I just replaced my factory Lagoon bridle a month ago after it snapped. Here is what I made for a replacement, took the bolt off (watch out for the inner washers) and put the plastic eyes directly on the shackle. Quiet and clean looking.

[crayiii]

Originally Posted by BobL1981

I just replaced my factory Lagoon bridle a month ago after it snapped. Here is what I made for a replacement, took the bolt off (watch out for the inner washers) and put the plastic eyes directly on the shackle. Quiet and clean looking.

That looks good! Is that 5/8" line? I was thinking about using 3/4 but I don't think I'll get the elasticity to make it comfortable so may stick with 5/8".

[BobL1981]

Where we were they only had 3/4”. I was a bit nervous too on the size but haven’t had any issues and we sit comfortable on it at night.

[singlespeed]

The weight of the bridle line, coupled with the length of the bridle above the water on Lagoons, should pretty much eliminate noise from the shackle when in zero wind conditions. If there are wakes in these conditions, other fittings on the boat will contribute more noise. Use of the thimble for this application is necessary due to the small size of the shackle. Boat manufacturer's are all making decisions based on perceived price points. Lots of small price points end up yielding the desired results from the manufacturer. Don't be tempted to drill our the attachment point to accommodate a larger shackle, that will weaken the setup. If you really find thimble noise to be an issue, cut a small square of neoprene and glue it onto the area where the thimble could contact the hull. Cheap, easy to replace.

[crayiii]

Great advice! Rather than opening the existing shackle to add a thimbled line, I'm assuming it would be acceptable to just add a second shackle off the factory one.

I would love to be able to do this easily while on the mooring.

[singlespeed]

Don't add another shackle. It will create another potential failure point. Just attach it to the existing shackle. You could always add a dyneema loop through the thimble and around the crossbar as redundency in case the shackle gives up the ghost.

[thinwater]

Just luggage tag it! You should be replacing this every few years, and doing it up all fancy will just delay that.

Plastic thimbles have a real tendency to break under high load. Based on testing (I do that), IMO they are just for looks and do nothing very useful. A length of webbing makes a better thimble.

I would not add another shackle. That's just going to cause wear on the none-to-big u-bolt.
---
There are good reasons that thimbles and shackles are minimized on series drogues. They serve a purpose on galvanized moorings, where things need to move and the metal is very rough, but not here. The luggage tag with prevent movement and chafe, simple, done.

[Breaking Waves]

OK -

Concerns

That factory shackle attachment point creates two concerns.
#1 it is small diameter - smaller diameter than the appropriate bridle line, and so is going to create a significant strength reduction if the bridle is directly connected to it. However, there are several (3 will be discussed below) easy ways to eliminate this concern.
#2 the loading angle on that shackle and on the whole connection point is not 'square' and will reduce the strength of that shackle by quite a bit. It would be interesting to know what other hardware/attachment options are available around that area. But we can create a better attachment using what you have shown in those pictures.

Solutions

#1 there are three ways to deal with the small diameter bend radius of that shackle.

(a) use a thimble in the spliced eye. You would have to open the shackle to insert the thimble. I will comment that neither nylon thimbles nor 'open' thimbles are correct here. Nylon thimbles will distort under load enough that they, in fact, will not correct the bend radius problem. And 'Open' thimbles (eg ones where the throat of the thimble is just two ends pressed together and not welded or connected), espically galvanized ones, will distort at about 60% of the line strength. Ideally you want closed metal (stainless) thimbles - like 'sailmaker' thimbles. This will create burrs on the shackle which is not ideal. So, both because it requires taking the shackle apart and because it will burr the shackle this is not an ideal solution.

(b) Make a lashing of Dyneema cord, smaller than the diameter of the shackle, between the shackle and a spliced eye with a thimble on the bridle line. This thimble could be the same stainless closed sailmaker one mentioned above or could be a large (aluminum) low friction ring (which would be my preference) because it does not have any metal to metal contact (unlike option a above). The small diameter cord will reduce the concern with bend radius and the lashing can easily be made stronger than the bridle line. This is dead easy to install because you don't have to open the shackle to do it, and there are not really any 'tricks' to creating a good solid lashing.

(c) Very similar to b above, but use dyneema climbing webbing loops between the shackle and the spliced brodle eye. Webbing essentially eliminates the bend radius problem. Pre-made climbing loops are inexpensive, readily available, and strong and very high reliability/consistency. There are a couple ways you could configure the webbing, but probably a 'basket configeration' would be easiest/best.

#2 To deal with the bad angle of load on the shackle you have basically two options - find another attachment point, which I will not consider unless you want to post some further pictures of the area/possibilities. Or use what you have to make the pull better aligned - this leads you again to solutions b or c above but instead of just looping the lashing or webbing thru the shackle, you loop part around the cross beam itself, just using the shackle to hold the lashing/webbing near the hull and taking the forward pull on the cross beam. That is not at all hard to do. From what I can see of the beam and its attachment, it should be way strong enough to take such a load, but a bit more detail would confirm that.

Bottom line - probably best easiest solution would be a Dyneema lashing around the beam, held to the shackle, to a large low friction ring at the end of the bridle line. This may be 'overkill' but it is easy to do and relatively 'correct' from an engineering perspective.