Best way to re-attach cam cleat to mast?

[OldFrog75]

Spinnaker topping lift cleat has pulled off the mast of a Beneteau 323. Can't see a way to get inside the mast to put nuts on the back of the loose bolts (1" x 3/16").

Given the relatively thin mast wall, will metal screws hold if we simply drill new holes or force larger screws into the existing holes.

What to do?

[David M]

Pulling the mast so you can thrubolt the cam cleat would be ideal.

But in a pinch, make an aluminum base plate for the cam cleat and then use multiple machine screws to thread the plate onto the mast, effectively distributing the load. That's if you are concerned with the wall thickness of your mast being able to provide adequate thread strength.

Use Tef-Gel on the threads where the stainless touches the aluminum...this is a must.

[MarkSF]

Some will tell you to drill the holes, tap the threads, and use new screws. Sounds like your threads have failed (galvanic corrosion?) so you'll need to go one size up in the fasteners, the hole, and the thread.

I prefer to use rivets. 1/4" ones in stainless steel are rated for about 2000 lbs each.

I suspect either technique will work fine in your case. Just use lots of lanocote or another coating to prevent galvanic corrosion.

[Cheechako]

Originally Posted by MarkSF

Some will tell you to drill the holes, tap the threads, and use new screws. Sounds like your threads have failed (galvanic corrosion?) so you'll need to go one size up in the fasteners, the hole, and the thread.

I prefer to use rivets. 1/4" ones in stainless steel are rated for about 2000 lbs each.

I suspect either technique will work fine in your case. Just use lots of lanocote or another coating to prevent galvanic corrosion.

+1 on the rivets.

[MarkSF]

I've been using the high strength stainless rivets from McMasterCarr, 2450 lbs each sheer rating.

A nice bonus feature is that the mandrel breaks off to leave the hole plugged.

[David M]

I don't see how a cam cleat is going to be held in place with a couple pop rivets unless you first make a mounting plate and attach the mounting plate to the mast with the pop rivets.

Pop rivets are great for shear loads but horrible for bending or pulling loads. With the line pulling above what otherwise would have been a shear load, the pop rivet would pull out. Besides, a cam cleat is designed to have a machine screw running through it and not a pop rivet. Also, a machine screw is stronger. A pop rivet is not going to be as strong under the same application. I don't think they make pop rivets that long either.

A more professional solution would be to have a mounting plate with enough wall thickness (1/4 inch) welded to the mast so that you could thread in machine screws without worrying about there being adequate thread strength with the mounting plate.

[MarkSF]

Oh yes, I see, nowhere to put the rivets.

[Cheechako]

Yeah, if the cam cleat is as you show then it will have to be a screw. The older cam cleats came on a SS flat base.

[MarkSF]

I can't say I'd use a cam cleat for a spinnaker halyard anyway, unless backed up by a proper cleat. Nearly capsized my last daysailer because the jib halyard came out of the cam cleat in high winds.

[Jim Cate]

Originally Posted by MarkSF

I can't say I'd use a cam cleat for a spinnaker halyard anyway, unless backed up by a proper cleat. Nearly capsized my last daysailer because the jib halyard came out of the cam cleat in high winds.

It isn't a halyard if you read the post... it is a pole topping lift which doesn't see nearly the load of a halyard.

And I think you guys are over engineering this simple task. A backing plate is great if the mast is flat where the cleat must go, but more of a task if it is curved (as is likely). Going oversize isn't an option since the screws must go through the cams. If the original installation lasted for years and only failed due to corrosion in the threads, I would simply move the cleat a few inches and drill and tap new holes. Then use some sort of anti-corrosive on the screws. I tend to use either Duralac (Aussie product) or anhydrous lanolin or anti-seize compound... they all work as well as Tef-Gel and are heaps cheaper.

Cheers,

Jim

[OldFrog75]

Thanks to everyone for the great ideas.

In the interim, we have a free "standard" cleat on the mast that works as a temporary solution - just not as efficiently as a cam cleat when racing.

[barnakiel]

Originally Posted by MarkSF

I've been using the high strength stainless rivets from McMasterCarr, 2450 lbs each sheer rating.

A nice bonus feature is that the mandrel breaks off to leave the hole plugged.

Others may correct me but I was taught the hole should be unplugged. Otherwise you end up with three different metals. We always punch the holes open when we rivet anything to the mast.

I am not sure many jammers lend themselves to rivets and I am surprised there was a cam cleat on a bene (because most any other maker uses jammers there).

?
b.

[MarkSF]

The catalogue page states that these rivets have an 18-8 stainless body, and mandrel. The mandrel thus does not increase the number of dissimilar metals.

[Cheechako]

Originally Posted by Jim Cate

It isn't a halyard if you read the post... it is a pole topping lift which doesn't see nearly the load of a halyard.

And I think you guys are over engineering this simple task. A backing plate is great if the mast is flat where the cleat must go, but more of a task if it is curved (as is likely). Going oversize isn't an option since the screws must go through the cams. If the original installation lasted for years and only failed due to corrosion in the threads, I would simply move the cleat a few inches and drill and tap new holes. Then use some sort of anti-corrosive on the screws. I tend to use either Duralac (Aussie product) or anhydrous lanolin or anti-seize compound... they all work as well as Tef-Gel and are heaps cheaper.

Cheers,

Jim

I wouldnt use one for a topping lift for sure. sound like a good way to get a debilitating bonk on the head.
It's amazing to me how many ways there are to avoid using a simple, functional and strong cleat!

[barnakiel]

Originally Posted by MarkSF

The catalogue page states that these rivets have an 18-8 stainless body, and mandrel. The mandrel thus does not increase the number of dissimilar metals.

Then I take back my comment.

(Still, I would punch in the mandrel, if it stays in the sleeve, thinking: less steel, less corrosion to alloy mast, less rust marks in the long run).

PS I use monel there, as I was taught, they have steel mandrels, hence my bias.)

b.