Attaching a new cleat to an old boom

[Captain Crisp]

Hi,
I'm planning to attach a reefing cleat to the front of my 50 yr old aluminium boom. Not sure I can access the inside so may not be able to get a nut in... Do people have any advice? How do I attach it and what materials should I use?
Many thanks,
Crispin

 

[prv]

Either pop-rivets or tap the holes and use machine screws.

Pete

 

[Old Harry]

Either pop-rivets or tap the holes and use machine screws.

Pete

A machine screw will not get enough threads in the wall thickness

http://www.rivet-nut.com/about-rivnut.html

 

[V1701]

I've recently riveted half a dozen small strap eyes to my boom to run lazy jacks from, not at all difficult but make sure you get a cleat with holes that you can get the head of the rivet gun into properly or it's not going to work. I used Duralac anti-corrosive compound (due to using dissimiar metals) and aluminium/steel rivets, I'm not sure which rivets would give the strongest hold but you can Google that...

 

[Old Harry]

I've recently riveted half a dozen small strap eyes to my boom to run lazy jacks from, not at all difficult but make sure you get a cleat with holes that you can get the head of the rivet gun into properly or it's not going to work. I used Duralac anti-corrosive compound (due to using dissimiar metals) and aluminium/steel rivets, I'm not sure which rivets would give the strongest hold but you can Google that...

Your loadings are far less than what the OP is proposing

 

[Refueler]

One of the main points was raised in another reply ... Duralac .... if you use an alloy / stainless cleat to ensure against dissimilar metal corrosion ... might sound crazy ... but years ago - it was not uncommon for tape to be used between the two metals !
If you use a Glass Filled Nylon cleat ... then its just making sure the pop-rivets are suitable for the alloy boom.

 

[Sean Carter]

I had the same problem and could not get a rivet in easily. So I bolted them all the way through the boom. You can get bolts longer than 100m if needed.

 

[Old Harry]

I had the same problem and could not get a rivet in easily. So I bolted them all the way through the boom. You can get bolts longer than 100m if needed.

PBO at its very best

 

[neil_s]

Since your reef cleat is on the outside of the boom, I take it there are no reefing lines inside it. I would simply use self-tapping screws. The load is perpendicular to the fastenings so there is not much chance of them pulling out.

 

[Refueler]

My 5m boat ...



I replaced the halyard cleats on the mast and the old rivets had corroded / set so I had trouble riveting the new. I used Self-tappers ... that was back in about year 2000 ..... still fine.

 

[Old Harry]

Since your reef cleat is on the outside of the boom, I take it there are no reefing lines inside it. I would simply use self-tapping screws. The load is perpendicular to the fastenings so there is not much chance of them pulling out.

They should be beyond reproach. might is NOT acceptable

 

[Refueler]

Monel Rivets are what are usually advised for fixings to alloy masts / booms as they are OK with Alloy and Stainless ... all you have to do then is apply a barrier - Duralac or Tape - between the metal cleat and alloy mast / boom ...

https://shop4fasteners.co.uk/monel-dome-head-rivets.html

 

[doug748]

Hi,
I'm planning to attach a reefing cleat to the front of my 50 yr old aluminium boom. Not sure I can access the inside so may not be able to get a nut in... Do people have any advice? How do I attach it and what materials should I use?
Many thanks,
Crispin

I did a similar sort of thing a few years ago.
I prefer to drill and tap, rather than use self tappers. Rivets tend to need a bit of specialist kit for this sort of thing, I have the kit but still use screws, which are handy to dismantle for inspection.

*Round off the ends of the screws on a drill or lathe, if you think they might snag the internals - in fact I do it anyway. Use the yellow stuff as advised.

* I should have said dome the ends of the screws, it's good practice. Not least if you ever have to stick your hands inside the thing.

 

[Boathook]

Monel poprivets would be my choice.

 

[chris-s]

Rivnuts? I also fitted a reefing cleat to our boom a month or so back and used rivnuts with duralac on the bolts.

 

[William_H]

I would use a tapped metal thread screw. With duralac. However in one place on my boom where I attached a saddle to the top to attach a reefing line I used metal thread 4mm screws. The screws are fitted head inside and nut on the outside.
I filed the sides of the tip of the screw then carefully drilled a tiny hole sideways through the tip. A piece of wire is used to "fish" from the hole to an accessible point at the end of the boom. Attached a thread to the end of the screw and using the wire was able to pull the screw into the boom and out through the hole. Now you can drop the cleat etc over the screw end and attach a nut. You can hold the screw tight against tightening the nut by gripping the flats on the end.
Only problem is that the screws extend outwards so you may want to cut off the extra length. Plus of course you have to have room to fit a nut into the recess of the cleat.
Having said all that I would take the reefing line back to the back of the cabin top via pulleys mounted under the gooseneck and at the base of the mast. For easy reefing especially if you have winches to pull the reef line tight. ol'will

 

[AndrewB]

It is possible to bolt if you can get one end off the boom, or even if there is enough room to slide in a small spanner.

While it can be done either way, it is easiest to put the bolt on the inside. If possible lay the boom so the bolt-hole you have drilled is facing downwards. Tie the spanner to a long bamboo pole, stick the bolt into the spanner jaws with BluTack, and manoeuvre up the boom until it can be worked through the bolt-hole. Attach the nut and tighten, pull clear the spanner.

Cutting a slot in the end of the thread enables the bolt to be held with a screwdriver on the outside while the nut is fully tightened.

 

[lw395]

Rivnuts? I also fitted a reefing cleat to our boom a month or so back and used rivnuts with duralac on the bolts.

Rivnuts are quite a good option. Particularly if the wall is too thin to tap.
However they may prevent the fitting sitting properly o nthe boom, unless you can recess the back of the fitting?

A backing plate inside the boom with tapped holes is another option.

 

[Poignard]

I once had an old aluminium roller reefing boom that had been converted to slab reefing and it had cleats at its forward end for the reefing pendants. These cleats were secured with self-tapping screws

One of these came off because the aluminium had corroded around the screws. Enlarging the holes to expose sound metal left them too large for new screws or rivets.

What I did was to through-bolt the cleat to a rectangular piece of aluminium (about 100mm x 50mm) with the corners rounded off and then rivet that to the boom with a rivet in each corner.

 

[Stemar]

All my eyes, blocks and other paraphernalia are either pop riveted using monel rivets or self tappered to the boom, which is, AFAIK, almost 50 years old like the boat. So far no problems in the best part of 10 years. Duralac is probably helping. I suspect a 50 year old boom is going to be significantly thicker than a new one, so significantly easier to fix to.