One Knot Failed in near Hurricane Force Winds (and other observations)

[Chotu]

so I am at an anchor for the winter. We had a very strong storm come through recently with South winds and I’m pretty open to the south.

Apparently these winds were blowing near hurricane strength if not right at hurricane strength.

how strong were the winds? Well, I had a deflated rib dinghy on the fore deck. It was filled with 2 x 12 staging plank lumber. Some fenders in it. A bunch of random things and some rope. It’s gone! It blew away. so these were pretty strong winds. I’m thinking that has to be hurricane strength. that dinghy has been sitting there for over a year.

we also had low tide like I have never seen when I left. There were shopping carts and ancient garbage in the water that were never visible and never hit in places that I go through all the time with the dinghy. docks were on the ground. the boat appears to have touched the bottom. Soft. Mud. No big deal. But one of the rudders touched and kicked up a little bit. About 2 inches of kickup. probably happening during the strong winds and incredibly low tides.

so that paints the picture that it was rough. I wasn’t here to experience it because I was on a trip to see family and go snowboarding

about the knots.

The 1st knot is a complicated rolling hitch type of thing that reverses at the end and ties a bitter end onto any other rope or chain. That is how the starboard side of my bridle attaches to the rode. The other port side of my bridle has a loop splice in it. I wrap the loop around the anchor rode twice and call it a day. on the Boat side, both of these go to my bow cleats.

so what happened as you can see in the picture is the side with the spliced loop slid up the anchor rode. No good. Then all of the load went to the other rolling hitch type thing that I learned to tie and that thing didn’t move a bit. You can see in the picture.

so now we have some real life results for these two ways of attaching a bitter end to any other rope or chain. The lazy way isn’t as good. Tying the actual knot is much better.

[Kettlewell]

When I had my small cat (32 feet) we had an anchor roller on each bow. The port side held the main anchor and chain. Typically, we would set the anchor from the port bow, back down to test, etc. Then I would tie on the bridle line that attached to bow eyes on both bows. I had the center of this bridle line marked with tape and I would tie that onto the chain with a modified rolling hitch. That knot never failed up to and including hurricane force winds. I did eventually suffer a snubber failure during a gale on my mono, but the line broke in the middle, not at the knot. It was an old undersized snubber.

[Knotical]

Originally Posted by Chotu

about the knots.

The 1st knot is a complicated rolling hitch type of thing that reverses at the end and ties a bitter end onto any other rope or chain. That is how the starboard side of my bridle attaches to the rode. The other port side of my bridle has a loop splice in it. I wrap the loop around the anchor rode twice and call it a day. on the Boat side, both of these go to my bow cleats.

so what happened as you can see in the picture is the side with the spliced loop slid up the anchor rode. No good. Then all of the load went to the other rolling hitch type thing that I learned to tie and that thing didn’t move a bit. You can see in the picture.

Isn’t this stating the obvious? A looped around line without any lock in it is expected to slide, especially when the other line becomes taut.

[Chotu]

Originally Posted by Knotical

Isn’t this stating the obvious? A looped around line without any lock in it is expected to slide, especially when the other line becomes taut.

Not according to many people on this forum that suggested it as a bridle attachment method

also, it doesn’t react at all the way you are imagining. It never comes loose or moves when it loses tension. The only thing it did was slide when it was under extreme pressure. Otherwise it stays put.

and to be very clear, it probably would not have slid on chain. But on the rope part of the rode it slid

[Chotu]

Originally Posted by Kettlewell

When I had my small cat (32 feet) we had an anchor roller on each bow. The port side held the main anchor and chain. Typically, we would set the anchor from the port bow, back down to test, etc. Then I would tie on the bridle line that attached to bow eyes on both bows. I had the center of this bridle line marked with tape and I would tie that onto the chain with a modified rolling hitch. That knot never failed up to and including hurricane force winds. I did eventually suffer a snubber failure during a gale on my mono, but the line broke in the middle, not at the knot. It was an old undersized snubber.

Agreed. The modified rolling hitch is fantastic. The harder you pull on it the tighter it gets. Like a Chinese finger trap

The spliced loop technique is kind of the same, but doesn't seem to have developed the same amount of grip.

It's been a good test. 13 months without a dock. Been trying these out the whole time to see which I liked better.

We have a winner

and honestly, it’s kind of relaxing and enjoyable to tie the modified rolling hitch whatever it is. I have a diagram of it somewhere I will dig up. Found it. This is what held.

are usually make about five loops where you see three of the tight ones in the diagram. Just for extra grip

[rslifkin]

Originally Posted by Chotu

Not according to many people on this forum that suggested it as a bridle attachment method

also, it doesn’t react at all the way you are imagining. It never comes loose or moves when it loses tension. The only thing it did was slide when it was under extreme pressure. Otherwise it stays put.

and to be very clear, it probably would not have slid on chain. But on the rope part of the rode it slid

You're describing the Prusik loop? On rope there is definitely a limit to how much they'll hold, depending on how many wraps the loop has around the line and the relative size of the 2 pieces of line. If both lines are close in size they may not hold well enough, especially if you can't get 3+ wraps through the loop. On chain, they hold very well due to the shape of the chain links.

[Chotu]

Originally Posted by rslifkin

You're describing the Prusik loop? On rope there is definitely a limit to how much they'll hold, depending on how many wraps the loop has around the line and the relative size of the 2 pieces of line. If both lines are close in size they may not hold well enough, especially if you can't get 3+ wraps through the loop. On chain, they hold very well due to the shape of the chain links.

Correct. The double Prusik loop did not hold.

I 100% found the limit for that lol.

[Knotical]

Originally Posted by rslifkin

You're describing the Prusik loop? On rope there is definitely a limit to how much they'll hold, depending on how many wraps the loop has around the line and the relative size of the 2 pieces of line. If both lines are close in size they may not hold well enough, especially if you can't get 3+ wraps through the loop. On chain, they hold very well due to the shape of the chain links.

I doubt it was a proper Prusik loop - seems like a similar sized line was used and he just threw 2 loops around the standing part.

A Prusik loop is a secure knot that climbers use with confidence, but it needs to be tied correctly, it will not slide when loaded.

[Chotu]

Originally Posted by Knotical

I doubt it was a proper Prusik loop - seems like a similar sized line was used and he just threw 2 loops around the standing part.

A Prusik loop is a secure knot that climbers use with confidence, but it needs to be tied correctly, it will not slide when loaded.

It was this. Does your understanding of one differ?

Doesn't look too "tied" to me. It's looped.



Same 1/2" 3 strand nylon for both the knot that didn't slide and the one that did. Both attached to 3/4" 3 strand nylon.

It slid.

It's not like I could use 1/4" bridle lines. 1/2" is small enough.

[Shrew]

Originally Posted by Chotu

about the knots.

The 1st knot is a complicated rolling hitch type of thing that reverses at the end and ties a bitter end onto any other rope or chain. That is how the starboard side of my bridle attaches to the rode. The other port side of my bridle has a loop splice in it. I wrap the loop around the anchor rode twice and call it a day. on the Boat side, both of these go to my bow cleats.

so what happened as you can see in the picture is the side with the spliced loop slid up the anchor rode. No good. Then all of the load went to the other rolling hitch type thing that I learned to tie

The knot that slid sounds like a prussik knot. Only, that should have 3-4 turns. If it slides at three, use 4 turns. 2 is too few IMHO.

[Knotical]

Originally Posted by Chotu

It was this. Does your understanding of one differ?

Doesn't look too "tied" to me. It's looped



It slid. Same 1/2" 3 strand nylon for both the one that didn't slide and the one they did. Both attached to 3/4" 3 strand nylon

This is a good photo, it gives you 2 reasons why yours failed - the tying line is of a much smaller diameter and it requires at least 3 loops.

The photo that you posted shows similar sized lines, and you said something like “I threw the loop twice and called it a day.”

I use a Prusik to climb the mast, the beauty of this knot is it will slide when unloaded and grip the larger line when under load.

Hope it helps.

[s/v Jedi]

I agree that the Prusik knot rules but the line used should be way smaller diameter (1/4” in this case, use stronger line if needed). I have never seen the three wraps as shown in animated knots slip.

Always have some of the loops at hand, also long ones. They save the day when you have todeal with stuff like an overwrap on a winch etc.

BTW, Chotu, that alone is a perfect reason for having a second winch wither on the winch table itself or in view of it so you can bring a line to that other winch. An overwrap can only be cleared if you take the tension off.

[dfelsent]

Originally Posted by Chotu

Agreed. The modified rolling hitch is fantastic. The harder you pull on it the tighter it gets. Like a Chinese finger trap

The spliced loop technique is kind of the same, but doesn't seem to have developed the same amount of grip.

It's been a good test. 13 months without a dock. Been trying these out the whole time to see which I liked better.

We have a winner

and honestly, it’s kind of relaxing and enjoyable to tie the modified rolling hitch whatever it is. I have a diagram of it somewhere I will dig up. Found it. This is what held.

are usually make about five loops where you see three of the tight ones in the diagram. Just for extra grip

I use the knot shown in the diagram and leave a long tail. I tie the same knot again in the tail. Seems to hold well.

[Chotu]

Originally Posted by Shrew

The knot that slid sounds like a prussik knot. Only, that should have 3-4 turns. If it slides at three, use 4 turns. 2 is too few IMHO.

Apparently so. The loop wasn't big enough to do more. I did theax possible.

I'll still take the knot I showed the pic of any day. It's unstoppable (pun intended)

[CaptTom]

I knew you were somewhere in the path of that big blow. I was wondering how you fared. Glad the boat came through OK, but sorry about the dinghy.