Adding 'Real' Cleats

[off-the-grid]

I'm looking to add 2 cleats, 1 on the inside of each bow, I'm on a 34' cat.

The purpose of these is:

laziness - keep my anchor bridal permanently attached, while maintaining use of my current undersized bow cleats for dock lines

reducing chafe - bridal line will lead straight off these cleats down to the anchor line, without bending over the edge of the deck, like they do now

stronger - putting in something bigger with significant backing for riding out "real" storms

I'm currently using 5/8" line for the bridle. Now the question is, what size cleat, and what kind of cleat. Is a 12" cleat going to gain me anything, or am I just going to be throwing money way? I'm thinking something about 10", since most of them seem to be rated for up to 3/4" line. Most 12- 12 1/2" cleats I'm finding are rated for up to 1" line. Probably overkill for a boat my size.

The other question is...brand name aside, which is stronger?
A cleat that uses 4 bolts in the base?


...or a cleat that has 2 larger studs, inline with the main body of the cleat?



Although the price is killing me, I'm really thinking option 2 is a much stronger cleat.

Why don't they just rate these damn things like they do shackles? Would make this so choice so much easier.

[Vasco]

Before you add the cleats check to see if where you're going to put them is strong enough. You will probably need backing plates and if it's a cored deck drill holes first and epoxy and then drill again. Another factor will be the angle of pull on the cleats.

[off-the-grid]

Oh yeah...and any recommendations for backing these things?

I'm thinking a few layers of cloth, then a sheet of 3/4ish" ply, followed by some more cloth, and then of course the small backing plates that come with the cleats, and/or large fender washers?

Hmm...if I go with option 2, I may be forced to go with the larger cleats, just because of the thickness, by the time I'm done laying everything up.

[off-the-grid]

Originally Posted by Vasco

Before you add the cleats check to see if where you're going to put them is strong enough. You will probably need backing plates and if it's a cored deck drill holes first and epoxy and then drill again.

Solid glass...and planning on adding backing. See my previous response.

These are going to go on the sides of the bows, closer to the water line. The main idea is to reduce chafe be eliminating that bend of the side of the deck.

[off-the-grid]

Or is there a cheaper easier, better way to do this?

The 2 biggest issues right now, are line chafing on the deck. See the attachment. Not my boat, but similar model, and close enough for you to get the idea.

And those cleats need some serious backing, which they don't have right now.

I'd be all for just adding backing to the existing cleats, and or/upgrading them rather than adding cleats if that will solve the problem.

[DaveOnCudjoe]

When you own a Farrier designed trimaran the designer is very available for this kind of advice. I would assume that Tony Smith is equally available and would only rely on his advice. Dave

[Bash]

I would go with the four-bolt type of cleat on my boat--that's got to be stronger than two welded-on studs.

I think the way to engineer this would be to start with what size line you want to build the bridle out of. Then go with the cleat best made for that size line.

[daddle]

I'd use a simple padeye. Less weight on the bow. Won't catch lines. Won't hurt the toes. Costs less. To eliminate rubbing on the hull use a bit of s/s chafe strip.

As implied above...the backing plate and hull structure is what's going to determine the strength.

[Vasco]

The padeye is a much better solution for a bridle.

[DaveOnCudjoe]

The Cassanova's used a strap eye around the stem of the amas on their Horstman trimaran Tortuga Too to attach the bridle to their parachute via a shackle to eliminate chafe. The length of the strap also spreads the load considerably. Dave

[off-the-grid]

Originally Posted by DaveOnCudjoe

When you own a Farrier designed trimaran the designer is very available for this kind of advice. I would assume that Tony Smith is equally available and would only rely on his advice. Dave

That's the same Tony Smith who doesn't believe in backing at all, and used cleats that you can barely fit 2 lines on.

I did ask this question in the owners group, though.


So are you guys talking padeyes on the sides of the bows, with the line spliced on?

I guess another potential solution would be simply backing the current cleats, adding fairleads to the edge of the deck, and some serious chafe gear on the lines?

[Bash]

Originally Posted by Vasco

The padeye is a much better solution for a bridle.

I like it too.

[thinwater]

Tough to get engineering answers on a forum.

I really prefer cleats, rather than fixed eyes, for cruising. It gives me the option, when needed, to vary the angle of the bridle so that the cat can point into the waves, when the wind and waves are not aligned. Your existing cleat placement would be fine, with good webbing chafe protection. I have had webbing chafe protectors, on a similar boat, last over 10 years.

If I were at a mooring I would still stay with cleats, for a boat your size; the carabiners many use to connect to them are potential weak points; far weaker than the cleats, in any case. Anything other than carabiners, for me, would be too inconvenient. For a big cat I would consider eyes. But engineering the eyes so that they are stronger than the cleats (remember, this is a pull-out rather than shear force) is going to require a very large backing plate, probably about 10-inch dia, dependent on the lay-up. The eye will also see a cyclical bending force. I would think 5/16-inch would do, but I think 1/4-inch would crack in time.

Casanova bails require a front beam, which you ain't got. And I've seen cats where the front beam DEFINITELY was not engineered to take a forward pull; it could be pulled out that way (the tramp holds the beam in)!

As for the strength of the existing cleats, the answer is simple; there have been over 1,000 Geminis built. Has anyone pulled bow cleats out (I don't know the answer)? That is probably a better measure than any amount of arm-chair wagering. Not knowing the exact lay-up of the boat in that area, we cannot judge. If there are are no backing plates, add some; I would go with aluminum or FRP.

All of the cleats I have seen fail have failed when the pull was upward (boat hanging from the piling). That places a terrible load on one end of the cleat, starting a tear. In your case, for a bridle, the pull will be slightly down or very slightly up (BIG waves) and so the load is entirely in shear. Failure would be very unlikely.

Why aren't cleats strength rated? Excellent question. It does seem that this is a safety issue and there should be an industry standard, of which I have never heard.

2 bolts vs. 4 bolts? The ONLY cleat I have ever seen fail had 4 bolts, corroded in the hollow, and the legs came off. Also a bad bet for any sort of pot metal chrome plated cleat. Probably, it is academic, since reputable cleats will not fail. I would not use the cast-in bolt type; I can't remove or inspect the bolt, and there are many good through bolt designs. In reality, a 5/16-inch bolt is rated for ~ 5,000 pounds (breaking strength) in shear and you will have 2; any 8-inch cleat will rated for what you need, aluminum or SS, and 10-inch is safe over-kill. 2 bolt cleats have bigger bolts than 4 bolt cleats.

No cleat design is likely to fail before the bolts, if in shear. However, if you have a lifting force, we simply don't have the product data to guess.

Don't use a short bridle; anything under 60 degrees really increases the forces; simple trig. For storms, use a long bridle to reduce the force (although, when the wind veers, all of the force will be on one cleat, at times).

Personally, I think you are cool now, after you check those backing plates. I think I would go up one size.

[off-the-grid]

On second thought, maybe I was worrying about nothing. Funny you should mention it thinwater. Turns out a Gemini actually road out Katrina, without so much as adding additional backing.

[GordMay]

Originally Posted by thinwater

... Casanova bails require a front beam, which you ain't got. And I've seen cats where the front beam DEFINITELY was not engineered to take a forward pull; it could be pulled out that way (the tramp holds the beam in)!

... Why aren't cleats strength rated? Excellent question. It does seem that this is a safety issue and there should be an industry standard, of which I have never heard ...

What’s a Casanova bail?

There are standards for “Design Loads for Sizing Deck Hardware” (ABYC H-40)

ABYC 40.4.4.3.1 “All fastenings of mooring points shall have a safe working load greater than, and be fastene3d to withstand, twice the permanent mooring loads in Table 1.”

Table 1 ➥ Design Loads for Deck Hardware - ABYC Section H-40, table 1 Cruisers & Sailing Photo Gallery

Unfortunately, I’ve never seen a manufacturer of deck hardware provide the information required to correlate specific products to the standard. To their discredit, they don’t generally provide any meaningful engineering information, at all.