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Need advice on Mast Cleat install


New Member
Bought the nylon mast cleat for $4 and am wanting advice on the install.

In 2013 other forum member posted he utilized #10 Stainless steel sheet metal screws along with 3m 4200 sealant:


The mast wall thickness is only 2.11mm.... so I'm thinking with that method the cleat is being held on with only 1 thread rotation on two sheet metal screws....DOESN'T SOUND EXTREMELY SECURE. I'm picturing the cleat getting ripped out in a good gust and getting hit on the head with the falling sail going overboard and getting tangled up and...well you get the picture.

So I'm thinking of utilizing a Aluminum Drive Rivet:


I would appreciate any and all comments and advice on how to best do this install.


beldar boathead

Well-Known Member
Screws are just fine. All the force is in sheer, so you don't need to worry about the screws pulling out. Although I'd only use an aluminum cleat, the nylon one is probably OK for the same reason - sheer.

Kevin Mc

Active Member
Beldar is correct - the nylon cleat with stainless screws will stay in place, given that the screws are almost 100% in shear. I speak from experience since that's what I have on my mast and it's held up to a lot of "intense" (high wind) sailing.

Speaking of cleats, the one on the deck of my 2005 hull snapped in two when I was untying the halyard when I was taking the sail down after I last went sailing. I had thought it was brass, but the material is definitely some lesser metal; salt water didn't agree with it. I replaced the broken that cleat with a nylon one from Intensity.


Well-Known Member
So I'm thinking of utilizing a Aluminum Drive Rivet: http://www.hansonrivet.com/drive-rivets-aluminum.htm
I think you were on the right track with an aluminum rivet. For resistance to galvanic action in your saltwater Sunfish, I'd use an all-aluminum installation. (BB's aluminum cleat + aluminum rivets + bonding agent). As one who has actually suffered a broken Sunfish ma$t, holes drilled into the mast should be tightly refilled with a rivet—and not pop-rivets or sheet metal screws.

IMHO, overkill would be an engineer-buddy's suggestion of yesterday. He'd form an aluminum backing plate to match the inside diameter of the Sunfish mast. Then he'd drive machine nuts into the plate—then use bolts to secure the backing plate and cleat to the mast. I don't know...that sounds like too much work! :rolleyes:


as a structural engineer by day, I'll voice my professional opinion that a small hole drilled for a screw and/or rivet should not have significant effect on the strength of a thin-walled tube.

if you sail in salt water, corrosion could perhaps become more of an issue as you've created a entry point for salt water, but using 3M 4200 or similar sealant should help to negate that problem. galvanic corrosion could be an issue with using stainless fasteners, especially with salt water, so as LVW mentioned, aluminum rivets might be a better option if that is a concern.

I have the small nylon cleat from Intensity - I was a bit disappointed in it, honestly. I had previously bought a black anodized cleat from Torresen Marine (now TOAD), and it feels much more heavy duty... but it is $18, and the Intensity one is less than $3. your call on which one is better long term.

beldar boathead

Well-Known Member
Further to Tag's comment, I have seen A LOT of saltwater Sunfish with mast cleats screwed in, and have NEVER seen one fail at the mast cleat. I have seen plenty fail at the deck or gooseneck, as there is a fulcrum there that facilitates the break. I vote with Tag.
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I installed a mast cleat. I used #8 (or #10) stainless sheet metal screws. I also used Loc-Tite marine epoxy between the cleat and the mast. Works good so far.