How often does a cleat snap?

[sailorboy1]

Never heard of a cleat breaking till this thread!

[colemj]

I would say that you had the bad luck of a casting defect with that cleat and nothing you did caused the problem. I think breaking a cleat is pretty rare - particularly in the use yours was in.

It is difficult to understand for me how it even broke that way with a casting error. It is a substantial size, you had figure 8's tied to it with the line exiting one of the free ends, yet it broke in the middle. If any of the forces were too large, or in the wrong direction, I would have expected a horn to snap instead.

Mark

[FamilyVan]

I can't speak to how common it is, but I have two large busted cleats on my bow. Both bronze cleats.

The storey I got from the previous owner was they got caught at anchor in a hurricane in the Bahamas, the brake was slipping on the windlass, so they secured the rode to these to big bow cleats. Apparently they both snapped at the same time. I'm not clear on whether the chain went directly to the cleats or if a nylon snotter was used, I suspect a nylon snotter was used.

I guess the only point of my storey is wind loads can and do break cleats from time to time.

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[valhalla360]

Originally Posted by four winds

I certainly wouldn't want tow your boat with mine in rough water.

Two equal weight boats could snatch harder than a piling/boat combo maybe? Because wave action could accelerate them in opposite directions. Maybe so.

Assuming the tow boat captain doesn't get stuipd, the forces at a dock could easly be much worse.

A 100' tow line is likey to stretch by feet when pulled thru a wave.

A 3' dock line will be lucky to strech by inches before it brings the boat up short.

Force = Mass * Acceleration.

Stopping a boat in inches means a much higher acceleration.

This is also why it's a bad idea to massively oversize your dock lines. You want them to stretch and absorb the forces.

[colemj]

Originally Posted by FamilyVan

I guess the only point of my storey is wind loads can and do break cleats from time to time.

Where did they break - horns, base or middle?

Mark

[FamilyVan]

The cleats are incorporated into a bronze fairlead. The aft horns snapped off.

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[Dsanduril]

Never seen a cleat fail in that manner, but would suspect (as does OP) short lines. As a fellow multihuller I would recommend having another look at Thinwater's posts #18 and #24. We're a tri, so a little different, we lead our springs to cleats on the float/ama, but our bow and stern lines always go to the main hull (and thus are always at least 10'/3m long).

With cats and tris we have very little curve to the hull, and you just can't get any horizontal pull when using the near side cleats for bow and stern. Using the outside hull (where space permits) greatly reduces the angle and loading on the cleats, and can (if you like) actually allow you to tie the boat up closer to the dock (since you now have a line that gives largely horizontal pull). At our home dock we actually extend past the end of the finger and (with the dockmaster's blessing) our bow line of necessity has to be tied to the float/ama (piling in the way of tying up to the main hull) so our bow line runs from the ama to the far side of the dock (since this is the very end of the finger and there is a piling there no on wants to walk there anyway). Again, this gives a horizontal pull which allows us to keep the boat where we want in terms of distance off the dock, while allowing much more stretch and movement.

[Nicholson58]

Originally Posted by msrcal36

G 10 fiberglass is the best choice for backing plates. No dry rot, 0% compression and very easy to work with. G10 Fiberglass Board

Agree - considering the boat weight and construction. We are 36 tons. Mine are all metal backed and bedded with epoxy & layers of FABMAT. G10 is not available nearly thick enough to spread the load over the required area.

We acquired our boat after hurricane IVAN damage in Lauderdale. The PO failed to remove sails. The genoa & cutter both unrolled partially. Before the sails were shredded, the force generated was sufficient to break the ears off of the 12 inch iron dock cleats. The boat sailed 90 feet into a seawall - etc.

I noted another post where the owner was killed by a cleat pulled out & snapped back under force of the towing line. This is an old and well known hazard. Drag line mining buckets can snap and destroy the machine when hundreds of feet of steel cable alone fly back into the winch. These machines are normally armored like a field artillery piece. Never stand where you can watch the tow line. Get as far as possible from it. Have anyone not needed go below or sit on the cockpit floor. Consider that the energy is the pounds of force in the line TIMES the length of stretch/2. The stored foot-pounds is equivalent to a small cannon.

[belizesailor]

Originally Posted by sakemoment

GordMay and noelex 77 - Thank-you for the warm welcome to the forum and thanks to all who responded to my post.

After reading all posts we decided that the reason the cleat snapped was very much in line with comments posted here by GrahamHo, hamburking and deblen.

We have 15 and 20 meter docking/mooring lines (not sail lines - see pics) however we agree that the angle to which we had the lines running from the cleat to the dock did not allow sufficient "give" for the lines to run and let the boat "dance" in the rough weather, the constant jolting eventually was just too much pressure for the stern cleat to handle. I will say that I don't believe it was the backing plate that failed. I'm sure you'll agree when you see the pictures.

....

Now that you've posted a pic, I've seen that same make & model of cleat fail in the same way.
Lines not being long enough is a fundamental problem. Also, those braided black lines are pretty & thus popular, but 3-strand nylon is better for dock lines because it has more stretch and thus shock absorbtion.

As you can see from the texture of the material at the break these cleats are cast, not forged. A forged cleat will be much stronger, but something to consider...it will also thus be able to deliver more load to the deck before failing...meaning the deck might fail before the cleat...easier and cheaper to replace a failed cleat. With dock lines properly rigged, loads should not get into ranges which would break the cast cleat anyway except in extreme situations...and having it fail then, rather than ripping a hole in the deck, might not be a bad thing.