Through bolting is stronger, easier, and cheaper (since you do not need the tools).
G
Cool. I can understand that for the mainsheet attachment at the end of the boom; the access is easy. But how exactly do you through-bolt, for instance, the outhaul cleat? Getting a nut (or turning/holding a screw) halfway down the inside of a nine+ foot long boom is a mystery to me.
If you are going to use 316 make sure you use an isolation /sealing compound such as 5200
drill it through to the other side
Not needed and will just weaken the boom.
Use the thread method mentioned above to thru bolt the fittings that place the fasteners under a tension load
(the cleat on the boom does not put the fasteners under tension, so rivets, even alum are fine for that)
How do you keep the bolt from turning while you tighten the nut, since you can't apply a screwdriver or wrench from the inside?
Extra long screw, held with vice-grips from the outside, then cut off once the nut is tight?
My old boom was through bolted on everything through to the other side by a North American Champion, Kim Zetterberg, and survived several time up to 40 knots, it is more than strong enough
I've read it before, and I am telling you there's noting wrong with it, granted its a 15 year old boom, so the metal may be a bit stronger, dunno, but I would do it again
don't go bashin till you've tried it yourself, it makes you sound like your uninterested in new/old ideas
In 30 years of sailing in lots of places I have never sailed in over a true 25 knots of breeze on any boat. 40 knots is southern ocean storm stuff.
Try SF Bay in the summer, Rob. In the afternoons it typically picks up to a steady 25 knots. As luck would have it, when I took my J24 sailing test for the cruising course, it was 30 knots (as measured by OCLC's electronic wind indicator back at the business office). I failed the man overboard portion of the test because it was impossible for me to head up quickly enough. All that said, I don't know why anyone would voluntarily go out in that wind speed. I went because I had an appointment with a financial penalty for backing out of it. It was too bad too. Because of it I gave up.
But we digress.
Steady 30 or gusting? How do they rig the boat for the test in those conditions? Blade and full main or do they reef the main. How many folks on board? I'm just interested in what an instructional school does.
Unless I'm stuck out in it, if it's blowing over 25 you'll find me on shore with my feet up and a beer in hand watching the carnage.
Steady, steady, steady, which of course makes it a lot easier. It also doesn't shift much. We started out reefed but I messed up the lines and we had to re--reef while underway. This was while we were still setting our sails while cruising in the marina and protected, with much less wind. We had two sailing her, one skipper and one crew, with a third student standing in the companionway and the teacher sitting on the transom rail. It took every bit of my strength to gybe, no crash gybe allowed. You have to pull the boom almost to the center and then gybe.
I like a dark beer.
How do you keep the bolt from turning while you tighten the nut, since you can't apply a screwdriver or wrench from the inside?
Extra long screw, held with vice-grips from the outside, then cut off once the nut is tight?
The good'ole heavy air, controlled jibe. That's the best way to go in the bigger boats. Those booms flying across in a snap jibe like we do in lasers will tear stuff apart and kill someone if there is contact!
OK, I reversed my lower section and turned an old broken upper section into a new boom this weekend. Here are the lessons I learned.
1. You want to have joined the class already, so that you have the class rule book and diagrams open in front of you while you work.
2. A metric tape measure would be helpful, or be very comfortable switching back and forth between mm and inches. Double check everything before cutting or drilling.
3. When cutting a mast uppper section down to a boom, a hacksaw works, but you'll want to use a miter box to get a nice square cut. Even WITH a miter box, one of my cuts wasn't as square as I would have liked.
4. The rule book measurements are made with the mast/boom end caps ON. But you're measuring with them OFF, from the raw end of the tube. Measure the thickness of the end caps themselves and take this into account. (Hint: the mast base is thicker than the other end caps.)
5. You're going to want to have new end caps in your hands before you start the job. I was able to save one end cap, but mostly removing them was a destructive operation.
6. West marine does have some stainless rivets in their general hardware section. That's good because the "general purpose" rivets you can order from APS/vanguard aren't always the right ones for the job. I found they were too short to keep the outhaul clam-cleat.
7. You can't just buy the rivet tool you need at the local hardware store, and local rental shops do NOT rent pneumatic rivet pullers. If I were to do it again, I'd order the following rivet puller well ahead of time:
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=41291
(Harbor Freight has great prices, but they don't specialize in "fast" shipping.)
This riveter is probably going to be good for one set of spars, more or less, as it is a cheap knock off of a commercial grade tool costing closer to $200 bucks. I bought a different riveter from Harbor Freight once and it gave out after I pulled a bunch of 316 grade stainless 3/16" rivets on my J/24. Which brings me to my next point.
8. The 18-8 grade stainless rivets supplied by vanguard are not very strong. It's not a wonder they work loose over time. I used them for most of the jobs, but I reattached the vang attachment point on the lower mast using 316 grade stainless 3/16" rivets. 316 grade stainless rivets are MUCH stronger (and are even harder to pull!)
If I did it again, I'd probably use the 316 grade rivets for
Vang attachment point on mast
Vang attachment point on boom
center mainsheet attachment point on boom.
You can buy 316 grade stainless rivets from McMaster-Carr http://www.mcmaster.com/
9. For the boom reinforcing sleeve: As mentioned above, the rules call for it to be placed so that it NOT at the end of the boom. I built a little wooden jig out of a piece of 1x2 lumber with two nails in it to hold it in the correct position lengthwise, and I clamped that to the end of the boom with a C clamp. Then I made a little hook out of coathanger that went through one of the two mainsheet block holes, and I had an assistant hold the sleeve tightly as close as possible to the bottom of the boom while I placed the first rivet.
Once those rivets were in place, I just went ahead and riveted the vang attachment point; so it ended up a little off of center to one side, and I'm pretty sure I don't care.
10. Just go ahead and figure on "through bolting" the end mainsheet attachment point. You need two 10-24x 1/2" stainless with fender washers and aircraft (nylon locking insert) nuts. You need needle-nose pliers and a tiny 4" crescent wrench. I found it easiest to have the boom right side up, tape the screws into position, then put the washer and nut on from the inside with my fingers, then remove the tape and tighten the screws. Do one that's further in first ;-)
11. When reattaching the outhaul attachment point you either need to drill smaller holes than you did for everything else, and use self tapping screws, or you need to use longer rivets than the "general hardware" rivets. ONE longer aluminum rivet comes with the new end cap; but you'll need an additional 3/16" x 1/2" rivet for the inside.
12. Having a drill press and an asssistant to hold the end of the boom is very helpful in getting the holes placed correctly. For the gooseneck fitting on the mast, which has six holes, If I were doing it again I'd only measure, mark, and drill only the center TWO holes initially, rivet those in place, then drill through the remaining holes using the the fitting itself as a jig to ensure perfect alignment. As it was, I had to redrill a couple holes on that fitting once I started riveting it because a couple of my holes were off by a sixteenth of an inch or so, and the rivet wouldn't fit.
Big job. I didn't keep close careful tabs on the time, but building the boom took somewhere between 8 and 12 hours. The mast lower section has a lot fewere fittings; so it was less than 4 hours. Haven't reversed the upper section yet. ;-)
Search keywords: laser reverse spar replacement rivet puller riveter boom reinforcing sleeve
etc etc...
1) Is this correct?
2) If so, is the sleeve only held on by these two rivets, or are other rivets needed elsewhere to attach it?
3) I am surprised when you order this part, there are no instructions as there are with some other parts.
I took the sleeve just past the mainsheet mid block, but first drilled and riveted the vang on. Seems to hold up okay in the breeze. To save your end caps, drop a heavy drill bit in through the gooseneck hole and keep tilting it end to end like a rainstick. The weight of the drop will keep your caps happy. I think throughbolting is not the answer, but every one will question that. A real rivet gun and stainless rivets from West Marine do the trick, just make sure the rivets are long enough to get a good metal ball going inside the boom. The sleeve is not the right diameter they sell, maybe you can find one at a specialty aluminum tubing shop. None here. Good luck and here's one to us cheapskates who won't fork out the big bucks for a boom. While you are at it, re-rivet the rivet on the topsection, and always make sure it faces aft when you rig up. assall.