How to size the thickness/strength of a bridle

[thinwater]

Originally Posted by Allan Corder

Hi all. Thanks for all the helpful comments. Just to clarify, the Manson Supreme has a slot along the shank, for tripping the anchor if necessary. I am not 100% happy with the chain to nylon splice on the main rode, so I am going to get a super strong shackle for the slot and attach the bridle arms to this, so I have 2 points to the anchor. Long bridle arms, I know and unconventional yes. More to tangle up yes, but if I keep lines taught when weighing anchor, shouldn't be a hassle and I've got ready made up trip lines. After considering your comments and the sailing I do and consulting with Richard Woods, I've decided on 12mm nylon...good and stretchy. When I get the boat back in the water, I can report back but that won't be very soon. ps. Manson Supreme is a great anchor. Thanks again.

Cruisers NEVER use the slot for the rode, because if the tide changes and the boat drifts up over the anchor, you will pull the anchor out. Just pretend it does not exist.


The tripping slot is also NOT the best place to attach a tripping line. The back of the fluke (best) or the roll bar (OK) is.



I'm not sure what "happy" with the splice means. Chain to rope splices are as strong as eye splices.

[fxykty]

Originally Posted by Allan Corder

Hi all. Thanks for all the helpful comments. Just to clarify, the Manson Supreme has a slot along the shank, for tripping the anchor if necessary. I am not 100% happy with the chain to nylon splice on the main rode, so I am going to get a super strong shackle for the slot and attach the bridle arms to this, so I have 2 points to the anchor. Long bridle arms, I know and unconventional yes. More to tangle up yes, but if I keep lines taught when weighing anchor, shouldn't be a hassle and I've got ready made up trip lines. After considering your comments and the sailing I do and consulting with Richard Woods, I've decided on 12mm nylon...good and stretchy. When I get the boat back in the water, I can report back but that won't be very soon. ps. Manson Supreme is a great anchor. Thanks again.

Now what you plan makes sense, but is still a bit silly. Let’s ignore where you want to attach the bridle shackle - wings has explained why using the slot is a bad idea.

If you attach the bridle to the anchor then what is the anchor chain for? You will basically have a rope rode, but with two lines instead of just one. Since you want the bridle to take the load and stretch the chain will have to be very loose and will not be carrying any load. Just get rid of the chain and use the rope alone.

In very shallow water I guess you could manage this, but what happens when you are anchored in 3m or more? You would need as much length in each bridle arm as you would in the chain, in fact an additional 30% or so more due to stretch. You would need three people to manage the bridle lines and chain on lowering and hoisting.

Irrespective of all that, 12mm seems a bit small for your boat. In lighter winds you don’t need any stretch from the bridle as the chain catenary takes care of the boat surging back and forth. It’s only in moderate wind over 20 knots when the chain starts to straighten out (less wind in shallow water) that you need a stretchy bridle to do its thing. That’s when a thicker bridle starts to work.

Just use 20% of the breaking strength to figure out the bridle size - match the working load to the chain and calculated anchor forces.

[s/v Jedi]

Originally Posted by Allan Corder

Hi all. Thanks for all the helpful comments. Just to clarify, the Manson Supreme has a slot along the shank, for tripping the anchor if necessary. I am not 100% happy with the chain to nylon splice on the main rode, so I am going to get a super strong shackle for the slot and attach the bridle arms to this, so I have 2 points to the anchor. Long bridle arms, I know and unconventional yes. More to tangle up yes, but if I keep lines taught when weighing anchor, shouldn't be a hassle and I've got ready made up trip lines. After considering your comments and the sailing I do and consulting with Richard Woods, I've decided on 12mm nylon...good and stretchy. When I get the boat back in the water, I can report back but that won't be very soon. ps. Manson Supreme is a great anchor. Thanks again.

[Sailmonkey]

Am I reading this correctly?

You want three lines leading from your boat to your anchor? What happens when you swing through 360deg? How much fun will it be to pull up that mess?

If you anchor with 20M of rhode, you’ll have a total of 60m of lines to futz with?

[meirriba]

I do not like your idea at all.
A bridle on a cat, to work properly, i.e. to lesson yawing with the wind, should pull the bows toward center. Your arrangement pulls almost only forward, the vector working to straighten the boat will be negligible.
Each of the legs of the bridle should be little less than boat width.

[Shrew]

This plan makes no sense. The bridle is there for several purposes.

1) To take the load off of the windlass and place the load on the cleats.

2) Soften the 'hit' that would be taken from a chain rode by allowing a nylon snubbers to stretch.

3) redundant connection of the snubber to the chain rode.

4) IMHO the boat rides straighter with a bridle. A single line snubber causes the boat to yaw a bit.

What problem are you attempting to solve by running two nylon anchor lines all the way to the anchor in addition to your chain, which has now been rendered useless?

[meirriba]

Originally Posted by Shrew

This plan makes no sense. The bridle is there for several purposes.

1) To take the load off of the windlass and place the load on the cleats.

2) Soften the 'hit' that would be taken from a chain rode by allowing a nylon snubbers to stretch.

3) redundant connection of the snubber to the chain rode.

4) IMHO the boat rides straighter with a bridle. A single line snubber causes the boat to yaw a bit.

What problem are you attempting to solve by running two nylon anchor lines all the way to the anchor in addition to your chain, which has now been rendered useless?

The boat is a cat.
Main purpose is item #4: stop yawing.
Other considerations (like less tension on the windlass etc.) are secondary on a cat.
His solution does not help this main issue at all.