Rivets or Machine Screws When Splicing a Mast?

[Chotu]

Originally Posted by col50

Do you mean it will be 5 ft long; or is it already done? Anything is possible if you sink enough money into it. I like to follow the KISS principle. Good luck.

I would have to check with the guy, but within a couple days it will be 5 feet. I don’t know. It’s in process right now. He’s working on it now.

I don’t know if you read my posts much, but I’m not really one for just sinking money into things randomly or unnecessarily. Here I’ll show you.

The quote for my rig and mainsail and blade jib? $65,000. That was before Covid.

I got the same rig for $6000. (No, i didn’t miss a zero) And I’m putting in an extension on it so it matches the sistership sailplan. We may have to race someday you know. Might as well keep it a one design. Lol. My rig includes both of those sails as well. Although they are bagged out and crappy. Also the main is a crummy triangle top. They’re good enough for the first year or two.

So, don’t think I’m some super rich guy just throwing money at projects because I have too much money to burn.

This is the best deal I could put together to get sailing.

That’s as KISS as it gets. Finding a non-existent spar section for a mast made in France by a company that is no longer in business when I’m in the States? The exact opposite of KISS actually.

[neilpride]

France spar has been absorbed by Zspar as long i remember , not 100% sure, to sad because France spar made in the past fantastic rigs, Z spar in the other hand its 3 steps down in quality V France spar.

Chotu, my imagination tells me that you have bought a used mast and you plan to put an extension at deck level.

6000$ its a good deal...

[Chotu]

Originally Posted by neilpride

France spar has been absorbed by Zspar as long i remember , not 100% sure, to sad because France spar made in the past fantastic rigs, Z spar in the other hand its 3 steps down in quality V France spar.

Chotu, my imagination tells me that you have bought a used mast and you plan to put an extension at deck level.

6000$ its a good deal...

Precisely.

Your imagination is very accurate. Ha ha

That’s exactly it. This used mast I bought was stepped on a cabin top. So it is a cabin height too short for my boat.

I’m splicing on a piece at the bottom at deck level in order to get it to the correct height.

It’s deck stepped on my boat.

And Col50: I was joking around a bit with you. I hope you didn’t take offense. I didn’t mean to offend you.

[SVPP]

Mine is joined with ss316 counterhead 1/4” screws with nuts on the back - no washers on the back. It has held up since 1977 and will see me out. My mast length is 20 m and is keel stepped

[neilpride]

Originally Posted by SVPP

Mine is joined with ss316 counterhead 1/4” screws with nuts on the back - no washers on the back. It has held up since 1977 and will see me out. My mast length is 20 m and is keel stepped

This puzzle me out, im really curious on how to reach those nuts once the mast its joined, aluminium nuts welded ? couple of windows on both sides?

[Bill_Giles]

The fastenings are merely to keep the sleeve in place. So it does not really matter what you use. Pop rivets come as ‘break stem’ where the head stays in the rivet and are used when you cannot clear the reverse of debris. ‘Break head’ allows the head to drop out to be cleared up. There are better rivets than pops for instance avdel. This gives a sealed hole and the pin needs to be milled off. I would be suspicious of bolts as they are not really permanent.

The mast manufacturer should be able to give sizes of rivets, numbers required and spacing between them and from the edges of the metal.

(PS I am a retired aircraft engineer)

[bleonard]

My experience with fabricated , sleeved masts is countersunk monel rivets preferred over machine screws.
Also had one 3 piece anodised and sleeved mast fail at the sleeves, meaning break into 3 pieces when sailing hard.
The factory built mast was in 3 pieces because of anodising tank length limits.
Conclusion was joints failed, above and below sleeves, because sleeves were straight cut, resulting in stress points at transition.
New mast, fabricated in two pieces because of longer single sections available, had internal sleeve tapered/ long angle cut, both ends, and was riveted.
Mast fabricated in late 80’s and still going strong.
Note masts we’re on ocean going catamaran so expected to work hard.

[Seabeau]

There is a basic "rule of thumb" based on the material's wall thickness. 3/16 and under rivets, larger, tapped and screwed with machine screws.

[s/v Jedi]

I agree with the angled cut on the sleeve. Also very visible on the sleeves we have at the vang attachment on the booms.

[Agprice272]

Originally Posted by Cheechako

The Pro's use rivets and structural epoxy on assembly between the sleeve and the two mast sections. I had one done years ago by Chesapeake Rigging. They did a lot of this type of custom work for expensive racing yachts etc.. The sleeve should fit closely.

Anything threaded will become threadless in short order anyway from corrosion.

I think rivets or welding. Screws could only be threaded to the inner sleeve because lining up the threads between mast and sleeve would be unlikely, so the threads are not gripping the mast at all. The holes in the mast will wallow out.

[Dave_S]

I'm just thinking out loud here so take it for what it costs.

I thought about the tapered ends of the sleeve but I couldn't be sure what the correct answer would be.

If you taper the sleeve it will spread (reduce) the stress loading on the material, however it will increase the loading on the fixings. And the opposite is true for a straight cut.

As the fixings are weaker than the material, my gut says a blunt-ish taper may be of some benifit rather than flat or a narrow taper.

I would be tempted to cut the ends as a continuous curve so there are no flats, shortest points are at centre when viewed from the front and back longest points are centre sides. So when the top of the sleeve is viewed from the side it looks like you copied the section of a symmetrical wave length from the centre of the bottom swing to the centre of the following bottom swing. Top to top for the bottom of the sleeve.

[Chotu]

I feel like the consensus here for rivets or screws has quickly become “nobody knows.”

I thought there was a right answer.

Apparently, there really isn’t one.

I had no idea this would be like asking mono versus cat, Rocna Or Manson Supreme, Rotella or Castrol.

[Dave_S]

Originally Posted by Chotu

I feel like the consensus here for rivets or screws has quickly become “nobody knows.”

I thought there was a right answer.

Apparently, there really isn’t one.

I had no idea this would be like asking mono versus cat, Rocna Or Manson Supreme, Rotella or Castrol.

We've done those.... This is new

[s/v Jedi]

Originally Posted by Dave_S

I'm just thinking out loud here so take it for what it costs.

As the fixings are weaker than the material, my gut says a blunt-ish taper may be of some benifit rather than flat or a narrow taper.

According to post 127 above, it was the material that failed, not the fixings.

[stormalong]

Wow, the thread that won't die! 135 posts so far. The truth is that both are used professionally and both will work. Since the splice is at eye level it is easy to monitor.