Single Line Bridle Rigging

[thinwater]

Originally Posted by belizesailor

Great! Actual data. Thanks for posting.

Can you post a link on making a side-spliced Y?

I'm puzzled why a prusick (sp?) hitch would lose so much strength if used to connect bridle to chain. For example, I'm thinking of prusick hitch to the mid section of 3/4 three strand nylon, tail of line for prusick hitch them somehow attached to chain. I don't like the idea of directly connecting it due to chafe, but several examples of that posted here. I would prefer splicing in a thimble and attaching via a shackle or similar....or at least a section of heavy cover for chafe protection inside a soft shackle loop.

Under this configuaration, I would expect the 3 strand to retain 100% strength because it has no knots or splices. The prusick hitch would adjust to diameter loss in the 3 strand due to stretch (could cycling at attachment point of prusicks hitch damage the 3 strand?). The line used for prusicks hitch would lose some strength due to hitch, but if its dyneema then even a 20-30% loss would still result in a WLL way above what's needed.

Opinions?

A y-splice is the same as an eye splice without the eye. Just splice a second leg into the main leg. This is how the Mantus bridles are made.

The weakness of the prusik is that it will slide at about 50% of the prusik cordage strength (polyester). Since the prusik must be ~ 30% smaller than the main line, that means it slips at about 25-30% when wet. That is good for a climber, as it absorbs fall energy before breaking, but not so good here. But in practice they work fine because we seldom see that sort of force, perhaps scope increases just a little, and you probably dragged first. They will not slip on chain. I've never heard of one failing. I use one sometimes, simply connecting a spectra loop to the bridle with a carabiner.

The reality is, with 2-leg bridles, they are always over built and they all work. Failures are either chafe on deck or contact with the bottom causing something to cut or unhook(this is the leading cause of non-locking hooks coming off--keep the bridle apex off the bottom).

[belizesailor]

Bought a few feet of Spectra to play with. I like the idea of a connection that will run thru the bow roller (downside to the alpine hitch/chain hook set up is that it is bulky). Thinking of a loop in one end to tie a prusiks hitch to the bridle and a toggle at the other end to attach to the chain.


Now I just need to get the hell outta the marina so I can actually anchor! Last projects should be done by this weekend and then off to the San Blas.

[belizesailor]

Tried out the Alpine hitch with Mantus chain grabber. Works fine, but quite bulky so must be attached forward of the bow roller.

I like the idea of rigging the bridle on deck with something which is compact enough to run thru the bow roller. So, made up a section of Spectra with a largish loop in one end and a small loop in the other. The large loop is for making a prusik hitch on the single bridle. The small loop I hitched to the eye of a small chain hook.

This makes for a very compact set up which runs easily thru the bow roller. Handy for both setting and retrieving. Been anchored on it for a few days now. Think I'll stick with this one.

[belizesailor]

Originally Posted by belizesailor

Tried out the Alpine hitch with Mantus chain grabber. Works fine, but quite bulky so must be attached forward of the bow roller.

I like the idea of rigging the bridle on deck with something which is compact enough to run thru the bow roller. So, made up a section of Spectra with a largish loop in one end and a small loop in the other. The large loop is for making a prusik hitch on the single bridle. The small loop I hitched to the eye of a small chain hook.

This makes for a very compact set up which runs easily thru the bow roller. Handy for both setting and retrieving. Been anchored on it for a few days now. Think I'll stick with this one.

Wrapping up our cruising season now. Spent late Feb thru late May anchored using the Spectra bridle hitch described above. No structured testing, but empirically worked great...despite what I think on closer examination is my technically flawed Locking Brummel Splice (but it held).

A bit faded from UV, some minor chafing, but otherwise fine. Given the strength of Spectra I suspect that even with some degradation it is still way stronger than needed for this application. Be interesting to load test to failure though.

Also quite easy to make up a fresh one for next season...and maybe I'll get the Brummel Splice right. ;-)

[BillYorde]

We recently replaced our single line bridle on our Privilege 42, the new one is three strand nylon with each leg spliced to the Chain Grabber from Budget Marine. Very happy with this arrangement plus there is room on the Chain Grabber to attach a hard or soft shackle if necessary.

Bill
Currently in Carriacou