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Crealock 37
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Discussion Starter #1
I want to install a clam cleat on the mast to temporarily hold the main halyard when hoisting. The idea is to hoist at the mast, cleat the halyard, then to the cockpit where I'll harden up on the halyard popping it out of the clam cleat. (Not my idea, stolen from a friend who does the same thing on her Crealock)

Can I use rivets to install the cam cleat? If so, what type rivet is recommended.

Thanks!
 

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I think you'd be better off drilling & tapping holes for machine screws. It's easy in an aluminum mast. Assuming you use stainless screws, put a little Tef-Gel or similar on them when you install.
 

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Old as Dirt!
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I want to install a clam cleat on the mast to temporarily hold the main halyard when hoisting. The idea is to hoist at the mast, cleat the halyard, then to the cockpit where I'll harden up on the halyard popping it out of the clam cleat. (Not my idea, stolen from a friend who does the same thing on her Crealock)

Can I use rivets to install the cam cleat? If so, what type rivet is recommended.

Thanks!
Dale--While our halyards and lifts are all led to the cockpit, we have been using jamb cleats on the mast to temporarily hold them in place as hoisting by hand is faster and, for at least 2/3rd's of most lifts, winches aren't really necessary. I originally fitted clam-cleats, as you describe, that would temporarily hold the lines while I moved back to the cockpit but would release the lines as soon as a strain was taken on them by the line running through the turning blacks at the base of the mast. The methodology works but I have found that the "horned cleat" style jamb cleat as shown here (a Schaefer cleat in this case) :



(with the jamb side facing down, of course) does work better and from any downward direction on the mast, hence a single such cleat on the center-line of either side of the mast can service all of the lines on that side. Since the loads are relatively low, one could use monel rivets but I think you'll find that machine screws tapped into the mast are somewhat more reliable. Just ensure that the screws are no longer than absolutely necessary, that you lube the threads with a little anti-corrosion material such as "TefGel" and, that you apply a thin coating of caulking to the undersides of the "feet" of the cleats and the portion of the screws that will remain within the cleat itself before screwing them in place.

FWIW...
 
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Crealock 37
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Discussion Starter #5
Thanks for the replies. I just stopped by WM and picked up a cam cleat but the jam cleat idea looks good….I could probably just replace the existing cleat with the jam cleat and not have to drill any additional holes in the mast.

Could not believe that the WM no longer carries Tef-Gel!
 

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Dale--While our halyards and lifts are all led to the cockpit, we have been using jamb cleats on the mast to temporarily hold them in place as hoisting by hand is faster and, for at least 2/3rd's of most lifts, winches aren't really necessary. I originally fitted clam-cleats, as you describe, that would temporarily hold the lines while I moved back to the cockpit but would release the lines as soon as a strain was taken on them by the line running through the turning blacks at the base of the mast. The methodology works but I have found that the "horned cleat" style jamb cleat as shown here (a Schaefer cleat in this case) :



(with the jamb side facing down, of course) does work better and from any downward direction on the mast, hence a single such cleat on the center-line of either side of the mast can service all of the lines on that side. Since the loads are relatively low, one could use monel rivets but I think you'll find that machine screws tapped into the mast are somewhat more reliable. Just ensure that the screws are no longer than absolutely necessary, that you lube the threads with a little anti-corrosion material such as "TefGel" and, that you apply a thin coating of caulking to the undersides of the "feet" of the cleats and the portion of the screws that will remain within the cleat itself before screwing them in place.

FWIW...
That horned cleat looks like a good idea. I was going to install a V cleat for the same purpose but the problem with a v cleat is it can catch a line at times when you want the line to run free (like when you want to drop the main from the cockpit). I'll install a horn cleat instead.
 

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Just ensure that the screws are no longer than absolutely necessary, that you lube the threads with a little anti-corrosion material such as "TefGel" and, that you apply a thin coating of caulking to the undersides of the "feet" of the cleats and the portion of the screws that will remain within the cleat itself before screwing them in place.

FWIW...
Stupid question, but hey, that's my specialty...

I get the TefGel to protect against corrosion due to dissimilar metals, but I don't understand what the caulk is for on the mast. I'm not arguing or disagreeing.. I just don't understand yet. Bedding hardware on the deck or hull.. sure.. protect the core and the hardware from moisture. What's the issue with the mast?

I'm all ears/eyes..thanks.

Barry
 

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I am able to use another method on my Catalina 320 that avoids the need for a cleat on the mast.

My halyards are led to the cockpit through a block at the base of the mast, then through a deck organizer to a line clutch, and ultimately to a winch on the cabin top. From what I've seen, that's a pretty standard set up. What I do is to partially open the line clutch (so it is easy to pull slack through it, but the line clutch will not let the halyard run backwards). I then run the halyard around the winch like a turning block, and back to where I am standing at the mast. I can "jump" the main halyard, then pull the tail of the halyard to me, to pull the slack through the line clutch. The clutch holds what I have hoisted. I repeat as needed to get the main up, then put final tension on with the winch. No extra holes needed in the mast, and no worries about dissimilar metals or accidentally drilling into the cables for masthead lights, antenna, etc.
 

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Freedom isn't free
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Why not rivets? I used alum rivets for mine, (as well as for sheaves and stuff), but I suppose depends on the size of the boat.
 

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Stupid question, but hey, that's my specialty...

I get the TefGel to protect against corrosion due to dissimilar metals, but I don't understand what the caulk is for on the mast. I'm not arguing or disagreeing.. I just don't understand yet. Bedding hardware on the deck or hull.. sure.. protect the core and the hardware from moisture. What's the issue with the mast?

I'm all ears/eyes..thanks.

Barry
Barry--

I suggest the caulk simply because water is a particularly effective/aggressive solvent and particularly so if one is moored in an area where one's rig is likely to be exposed to soot or exhaust gases (which virtually everyone is that has the misfortune of being in a marina that hosts power yachts as well as sailing yachts, to say nothing of being close to motorways). The soot that unavoidably collects on one's rig/mast invariably contains sulfur which, when exposed to moisture from condensation, rain or what have you, forms acid. Think Water (H20) combined with Sulfur (SO) yielding Sulfuric Acid (H2SO4). This "solvent" will eat into connections, particularly between dissimilar metals, promoting corrosion, unless it is kept out of the connection by a caulking compound of some type. 'S'not rocket science. It just is what is.

FWIW...
 
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Old as Dirt!
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Why not rivets? I used alum rivets for mine, (as well as for sheaves and stuff), but I suppose depends on the size of the boat.
SHNOOL--One can certainly use rivets although they can be more problematic than tapped/threaded fasteners. Properly done, however, they will work quite well. The question is the measure of "quite well/properly done". If a threaded connection is "screwed up" there is usually no mistaking the fact. If a riveted connection is screwed up, it can/often remain(s) unseen/discovered until it fails entirely. Of course, considering the proposed application discussed in this thread, that would not be catastrophic, merely inconvenient, no?

FWIW...
 

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Threaded connections are easy to inspect, but often very weak because the mast is so thin. The mast wall on his Crealock 37 is 4mm (.157") thick. A #10-24 bolt has a thread every 0.041", so there will be about 3.5 threads of engagement. That is borderline strong enough. A lot of us with smaller boats will have masts that are thinner and threaded machine bolts will be even weaker.

A properly done stainless rivet should be stronger. I expect that a properly done aluminum rivet is still strong enough. Isomat (who made his mast) uses rivets for all mast and boom hardware, which seems like a good enough reason to stick with them.
 

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A properly done stainless rivet should be stronger. I expect that a properly done aluminum rivet is still strong enough. Isomat (who made his mast) uses rivets for all mast and boom hardware, which seems like a good enough reason to stick with them.
Don't you have access to Monel rivets? If so, those are best, strong and no need for the exclusive Tuff-Gel.

Usually I go for bolts, with a locknut (+ washer) on the inside. That was what I use when fastening new cleats and similar on my mast. But in this use, rivets are sufficient.

I notice that my kicker, both on boom and mast, rivets are used. Works since ~25 years. (boat size ~40 ft).

/J
 

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Over Hill Sailing Club
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I've used both machine screws and s.s. rivets to attach things to the mast. Both work well. I used both to attach mast step plates and see little difference in holding ability although I like the fact that rivets do not depend on threads in aluminum. If there were any upward stress I would not depend on a few threads in aluminum without a washer behind but it is mostly shear strength in this situation. A cam cleat would be easy to rivet because it has a flat plate but they could be difficult for a regular cleat because most are countersunk for the bevel on screw heads or require longer bolts. You could adapt something or use washers I suppose. You need a heavy duty rivet gun for large s.s. rivets. It might be possible to get some thru-bolts in the next time the mast is down with a long stick and a lot of cussing:)
 

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I ask as on my 25 footer, I riveted in the gooseneck fitting, the bracket for the boom kicker, and also the cam cleats on the boom. The original hardware in all these places was originally riveted.
 

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Cam cleats will typically need 1.5-2" of hardware to go from the top of the cleat to the inside of the mounting surface. For this reason, I suggested drill n' tap machine screws. If you want to source 2" long rivets, then go for it. However, you also have very little control on how much pressure is applied to a rivet. Cam cleats, if over tightened, will hang open and not spring shut.
 

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Note that the original poster said clam cleat, not cam cleat. Clam cleats are designed to work with rivets.

I use riv-nuts when I need a threaded home in my mast for something like a horn cleat. Isomat used special horn cleats on my mast that had four low profile mounting holes instead of two high profile ones...
 

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It has a Lafiell mast, not sure of dimensions but you make a good point re: wall thickness to accommodate a screw.
Ah, I was trusting what Rig-Rite said about your boat. I'm very familiar with Isomat masts because my Pearson has one. I have two friends with Yankee 30s that have Lafiell masts, but I haven't looked at them as closely.
 
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