attach new outhaul fairlead- rivet or thru-bolt?

cskudder

cskudder

Active Member
I recently upgraded a 1973 boat to a 6:1 outhaul. The fairlead on the end of the boom is worn + loose and I'm going to replace it with a new part. I'm considering thru-bolting the aft end of the fairlead, which is the end that's under uplifting tension as the outhaul pulls, and the fairlead tries to pivot around its forward end. I use a clew hold-down strap.

Anybody have any experience with thru-bolting this, or any opinions about whether that's a good idea?

thanks
 
Thru bolting the outhaul fairlead AND the eyestrap for the mainsheet block are good ideas on older spars where the holes may be slightly enlarged due to corrosion/wear.. IMHO it's nice to do it once and not worry about them pulling out 5 years down the road

IIRC, the back hole of the fairlead goes thru the end boom cap, so a SS rivet is the best you can do in the back hole, but thru bolt the front hole.. (When the outhaul is pulled on, the load on the fairlead is mostly forward not up anyway)
 
Thanks. In the back hole, I'm thinking of drilling all the way thru the end plug, to+ thru the bottom of the boom - so bolting ALL the way thru the whole 2 inches or so diameter of the boom.
C
 
cskudder said:
... I'm thinking of drilling all the way thru the end plug, to+ thru the bottom of the boom - so bolting ALL the way thru the whole 2 inches or so diameter of the boom.
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That's what I did just a couple of days ago when I finished my new boom.
I also through-bolted the front fitting, too. It's easy to do, and the machine-screw head fits the fairlead perfectly.
FWIW, a 2 1/2" #10 machine-screw is almost the perfect length.

Cheers,

Geoff S.
 
no just put a slightley longer monel rivet through with anti corrosion paste on never replace a rivet with a bolt if you dont have to it looks crap and if you cut the bolt and dont file it it can leave it sharp and if you dont cut it off it can catch so can the not or bolt head left sticking out witch you dont get with a rivet i would strongley reccomend using a rivet over a bolt on a boat.
 
Like GeoffS, I through-bolted the forward end of the fairlead because this is where 99% of the shear stress is concentrated, and riveted the after portion along with the end cap. Below find a thread with some pics. You will also see a trick using washers to make sure the rivet is properly seated and snugged up with your rivet gun. HTH

http://sailingforums.com/threads/nuts-bolts-rivets-boom-repairs.7679/#post-46915

no just put a slightley longer monel rivet through with anti corrosion paste on never replace a rivet with a bolt if you dont have to it looks crap and if you cut the bolt and dont file it it can leave it sharp and if you dont cut it off it can catch so can the not or bolt head left sticking out witch you dont get with a rivet i would strongley reccomend using a rivet over a bolt on a boat.
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With all due respect, how something looks is insignificant compared to how it performs inder load. Somehow I can picture many sailors saying "yeah, my eye strap looked really great right up to the point when it snapped off." If you take your time, and use a Dremel tool, through-bolted items will look just as "cool" as riveted and makes for one less thing to worry about.
 
My personal preference is if the rivets have become too loose is to remove all the fittings from the boom, cut the top section down and make a new boom. Whilst you will need to buy a new top section, the chances were that underneath the collar, the rivet hole was in as bad as condition and likely to break in the near future. The chances are anyway that there is a bundle of old broken top sections in your club looking for a new home.

Whilst I used to muck around with bolts in the days when we had to through bolt the blocks as well. In the 15 years I've just used monel rivets with anti corrosion paste are just as good even after several seasons of use.
 
While Alan's idea has some merit, there are those who cannot afford a new boom, or even a "practice" one. Also, even if you get a new boom, there is still a fundemental weakness in the design. Let's consider through-bolting with curved fender washers on the inside of the boom. If you assume that the diameter of the fender washer is only 50% larger than the head of the screw (bolt), then the area which the bolt is pulling on is increased by 125%. Simply put, the pulling force exerted by the block(s) via the eye straps is now spread over an area 125 times larger than if a rivet or bolt was used alone. This means that the force per unit of area is drasitcally reduced to the point where the plastic block itself would probably be compromised before the bolt ever pulls out of the boom. I don't care if the rivet is made out of unobtainum, it is impossible to spread the force over such a large area without using a washer on the inside of the boom, and the only method I know of at the moment is through-bolting.

BTW, if you take a mast top section and turn it into a boom, doesn't that change its function and therefore make it illegal? (I'm just kidding)
 
thru bolt or use bigger rivets, if its loose it WILL come off while you're sailing

I repaired a few old booms for a jr program with bigger rivets and they have been rock solid for years, same thing also works with the boom blocks if the fairlead breaks loose

you'll need to find a Marson "Big Daddy" to put bigger rivets in, the marson also works great with the regular sized rivets if you change to the new blocks
 
I would not argue the point about good rivets, but you do run into a bit of a Catch 22. Specifically, aluminim rivets are compatible with the aliminum boom, but are not very strong. Stainless rivests are the strongest available but causte galvanic corrosion of the boom. There is no cure for the latter, but you can mitigate the problem by using Lanocote or similar to keep the pieces somewhat isolated, but it is almost impossible to get a lot of it on the inside of the boom. Therefpre when I bolted my eyestraps, I was able to spread a thick layer on the washer, insuring that there is a decent barrier between the washer and the inside of the boom. The next time I do it, I will use some plastic sheeting as well as the lanocote. I also used paper thin mylar washers (available at any hardware store) between the eye strap and the outside of the boom.
 
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