Snubbing with a splice

Sorry you had bad luck with the chain hook. With 50 deployments of this snubber, I have yet to have the hook come off. I attribute that to a large loop from the chain hook to the bow roller (hanging down atleast 10') and bringing the loop back to the hawse pipe before going to the roller (post #45 picture #5). IMO, people who have had problems with chain hooks don't have enough slack loop in the chain between the chain hook and roller, and allow the chain from the bow roller to rub against the chain hook. Understand that a chain hook is secure by being under tension, thus the need for a big loop of chain between the bow roller and hook. My unsubstantiated assumption is that failures occur when the chain from the bow roller rubs and eventually trips the chain hook. Securing the chain back to the hawse pipe eliminates that rubbing. When properly deployed, the chain comes from the anchor to the chain hook, and then to the loop. If the chain loop crosses over the chain going to the anchor it needs to be rectified by pulling up the other end of the loop until the chain isn't twisted. Then drop the loop and it will remain untwisted if setup in picture 5.

Regarding the length question, I only have about 4" between the splices.



I keep going back and forth on whether to lengthen to 16" or not. While having more single line stretch is a good thing, my boat (maybe most boats) doesn't pull uniformly on both lines as it always wonders to some degree. So in essence, I get stretch on one or the other line from the hawse pipes. Further, with a chain rode, you get some degree of snubbing effect lifting the chain off the seabed as the slack is pulled out. I find some advantage to being able to see the chain hook at the surface in calm deployments.

If I were making your snubber, I would allow 4' from the splice to the end of the line. After making the splice, I would carry it down to the boat and set it through the hawse pipes. Ideally adjust the length until the junction splice isn't touching the leading edge of the bow (mine touches which annoys me). Then decide whether you want the hook near the surface or not. If you splice it without shortening it, you can always shorten it and resplice it later.

If you make another one, I might go 5/8" line. 1/2" on a 40' boat in a hard blow would make me nervous.

Ted

Thank you for the recommendations. I might very well bump up the line size to 5/8" for the patented OCD anchor bridle I'm getting ready to make, although the tensile strength of the 1/2" line I'm using is well over 6000 lbs and even factoring in the splice strength loss , I would be surprised if the anchor held fast with 3000 lbs of pull, much less the deck hardware, before the line parted! I don't want to reduce the stretching effect too much, but as you alluded , better to be safe than sorry.
An interesting sidebar: while researching the line strength reduction of a splice, I came across this publication showing the effect different bridle angles have on the load. It seems , according to this particular article, that the stress on the loading point (the anchor snubber hook, in our case) changes dramatically according to the angle (length) of the bridle. Am I reading this diagram correctly? I am not going to overthink my damn anchor tackle but still found it intriguing.

O C Diver said:

If you make another one, I might go 5/8" line. 1/2" on a 40' boat in a hard blow would make me nervous.

Click to expand...

I would think part of the equation is length of snubber. Function of the snubber is to reduce snatch load on both deck and anchor - a longer snubber of 1/2" might be better than a shorter length of 5/8" - some really large fish are landed on comparatively low-test monofilament line due to shock absorption. Of course too much stretch might cause some recoil effect, and also causes a fair amount of friction (and wear) within the fibers.

My boat is about 30k lbs. For spring lines, I use 35-foot 1/2" 3-braid. I use the same line as a snubber with Camel Hitch. My thinking is a properly sized spring line is probably a properly sized snubber too. But that's just how I've done it without a lot of thought.

Peter

mvweebles said:

I would think part of the equation is length of snubber. Function of the snubber is to reduce snatch load on both deck and anchor - a longer snubber of 1/2" might be better than a shorter length of 5/8" - some really large fish are landed on comparatively low-test monofilament line due to shock absorption. Of course too much stretch might cause some recoil effect, and also causes a fair amount of friction (and wear) within the fibers.

My boat is about 30k lbs. For spring lines, I use 35-foot 1/2" 3-braid. I use the same line as a snubber with Camel Hitch. My thinking is a properly sized spring line is probably a properly sized snubber too. But that's just how I've done it without a lot of thought.

Peter

Click to expand...

To my way of thinking, a boat should have 2 snubbers. One for less than 30 knot expected gusts in moderate protected waters, and one for storms with with larger diameter and longer lines.

Ted

boomerang said:

Thank you for the recommendations. I might very well bump up the line size to 5/8" for the patented OCD anchor bridle I'm getting ready to make, although the tensile strength of the 1/2" line I'm using is well over 6000 lbs and even factoring in the splice strength loss , I would be surprised if the anchor held fast with 3000 lbs of pull, much less the deck hardware, before the line parted! I don't want to reduce the stretching effect too much, but as you alluded , better to be safe than sorry.
An interesting sidebar: while researching the line strength reduction of a splice, I came across this publication showing the effect different bridle angles have on the load. It seems , according to this particular article, that the stress on the loading point (the anchor snubber hook, in our case) changes dramatically according to the angle (length) of the bridle. Am I reading this diagram correctly? I am not going to overthink my damn anchor tackle but still found it intriguing.

Click to expand...

Regarding your line strength. That's factory new line rating. It only decreases from there with use, abuse, and U/V exposure.

Imo, it's important to calculate snubber bridle loads based on single line stretch. Changing wind direction can put all the load temporarily on one line.

Your chart is also very applicable to dinghy lifting harnesses.

Ted

boomerang said:

… Am I reading this diagram correctly? I am not going to overthink my damn anchor tackle but still found it intriguing.

Click to expand...

No, you are not reading it correctly. In your application the charts will be reversed. The load on the hook remains the same but the load on the two legs of the bridle change.
The narrower the angle at the hook end, the less load on each end to as low as 50%. The wider the angle, the more load on each leg.

A 30 degree angle or less, each leg if pulling equally would each bare about 50% of the load. Widen that angle at the hook to 120 degrees and if equally loaded, each would bare 100%. Another way of saying that is there would be a two hundred percent load on the bridle. (Not the hook.)

I had a bridle like you are describing. I had a splice that formed a "Y" just before the chain hook (in my case a Mantus hook). The splice started coming apart after about 250 days at anchor (one year in my case) and a few +40-50 kt blows.

A better option is to have 2 independent lines with eye splices and thimbles joined at the hook with a shackle. Much stronger than a Y splice.

Started using a Winchard hook on 10 mm chain on my cousins Amal Super Maramu in 2015. Have used the same hook on my 3/8 chain. Never a problem with it falling off. Do always leave a loop.

Photos were taken when we picked up the boat. Have since spliced in ss thimbles. Shackle is also safety wired.

Rob

Meant to post this in the chain hook thread, sorry. Moderators please feel free to move it if you wish.

La Sirena said:

I had a bridle like you are describing. I had a splice that formed a "Y" just before the chain hook (in my case a Mantus hook). The splice started coming apart after about 250 days at anchor (one year in my case) and a few +40-50 kt blows.

A better option is to have 2 independent lines with eye splices and thimbles joined at the hook with a shackle. Much stronger than a Y splice.

Click to expand...

Maybe you could explain why you think the splice started coming apart and why it wouldn't happen with two spliced eyes shackled together.

Ted