Discussion in 'Laser Talk' started by bjmoose, May 21, 2007.
I through bolted and the boom broke the next day in 35 at Santa Cruz.
How about a mixture of both? Through bolt half and rivet half? I've always had riveted spars. Over time the fittings can loosen up a little. At that point I just re-rivet them. As long as you inspect and repair as needed you should never have a problem.
I have to question the 40 and 35 knot things. Guys, you do realize a knot is 1.2MPH? So, 40 knots would equate to 48 mph wind. That's over tropical storm strength.
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.
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!
Sounds like a good school. Sometimes you hear things like, "we had 8 people on the J24 for our MOB test." That would not be fun.
I'm not so much into dark beer. I like the pale ale's or better yet scotch.
San Francisco? Try Santa Cruz. As luck had it for the NorCal Championships, where it often blows in the 25 NAUT range, a front came through and while trucks were overturning on the bay bridge, it was even windier on the coast in SC. Bravery vs. Idiocy, 14 boats ventured out and one lap was completed and the race was shortened due to increasing winds. At the leeward mark in 3rd, the boom snapped in half, the one I spent all day reinforcing for what I knew was coming, as I had raced here thirty years before in the O'Day finals (and not once inbetween!) and the wind was easily 35 with a running 15 foot swell. My blocks pulled off the boom that day, deja vu. So back to 2008, and half the boom with razor edge flailing in the wind, I turned the boat downwind to keep the boom away, and headed to the nearest beach. Rescue boat tried to tow me, saying the waves were too big risk it having no sail power, but I figured the boom and the stitches to come were a poor option, so I let go of the tow line and headed for a thin stretch of beach inbetween cliffs. When I saw a lone surfer, I knew I would at least have help, and timed it right so the wave snockered me into the beach and I flipped right up onto it. The lesson here is, get a new boom and a bucket of beer and forget through bolting and sailing in Santa Cruz in a cold water hurricane. I lived on Maui most of my life as a windsurfer so I know strong wind strengths. There is no stretch of the strength here, well, maybe a little.
No I believe Merrily. Having sailed in the Bay weekly for the last four years, this is not uncommon. Actually I remember that day, that Merrily mentioned, and it was howling. She sailed with us that same weekend. Last night (5/1/08) was beautiful and basically an easy night on the Bay. You can see by the records that nearer to the East Bay where she was sailing was in the mid 20s, http://windandtides.com/ . Just a side note...
Sailstarz, that is why I did not go. I have learned my limitations....hehehe....stories to tell the grandkids though...LOL
I don't doubt Janet. My thing was people always say, "Oh it was blowing 30!" when in reality it's not very often at all that boats are racing in 30 knot plus conditions and quite honestly never 40! I'd argue against the laws of physics allowing a full rig laser to make forward progress in 40 knots of breeze. Even in the rare instances something like this does occur it is because you got stuck in a building beeze. I've never seen an RC start a race in a steady breeze greater than 25 knots.
There are things that happen that make us thing it's blowing 30, but put a wind guage on it and it's probably 25 at best in the gusts.
Things like breeze against the tide, or in shallow water can build up a steep/short/brutal chop. Offshore systems can drive huge swells on an ocean course and in 20 knots of breeze it might feel like 35, but it's not really.
From the posts I'm seeing there are not many showing racing in true and verifyable 30 knots plus conditions.
I was just curious, has anyone ever tried a toggle bolt? They do come in stainless steel and are kind of made for an application like this. For lack of a better site, this one gives a pretty good description http://www.mutualscrew.com/products.php?pid=4934 .
I'd agree with that! I can remember as a lad being told of a speed test being done with some sort of radar gun thingy onboard Lion New Zealand, which was a 78' Maxi built for the '86 Whitbread. they claimed that the end of the boom was doing over 700km/h in a hevy weather crash gybe.
Dont think I'd wanna be hit by that!
OK, while this is a lot of explaination, I'm still confused. My question only concerns installing the rinforcing sleeve, not cutting off top section spars and through bolting hardware.
The class rules are pretty clear as to where it goes, and it would appears that the forward mainsheet boom block rivets need to be drilled out then the sleeve positioned per class rules, new holes drilled in the sleeve, and new rivets going through the boom block's padeye, the boom and boom sleeve. I would assume part of the trick is to keep the sleeve tight against the boom during all of this and a broom handle wedged inside (or similar) might work to hold it in place.
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.
As with most things there are numerous ways to achieve the same result. I used a tape measure to position the inner tubing. First set the boom up so gravity helps you out. Centre the inner tube so it lies more or less plumb and horizontal, but just 600mm or so from where it should be. Slide the tube in using the end of a locked tape measure until the tape measure reads the correct distance. Find a scribe or something else with a sharp end and align the holes in the boom with the ones in the inner tube, or use the sharp ended tool to carefully turn the inner tube until the holes align.
If you have no holes in the inner tube, it's easier. Use a permanent marker through the boom eyestrap holes to mark one position, then pull the tube out, drill the hole and go back to step one, but push a rivet into the hole you drilled once it's lined up again. Then mark the others and drill them. Then go back to step one for the final run.
Thanks for replying. Since I would be reinforcing an older boom with all the hardware already attached, can I just leave the vang hardware attached? or do I need to remove it and reattach riveting through the sleeve? Seems like because the sleeve is smaller, it would fit without removing the vang. Also when I ordered the replacement sleeve, they sent a replacement end cap, so saving it is not really an issue. They also sent 3 or 4 SS rivets. I assume that two go for the mainsheet block and one or two are for the end cap. Does this sound right?
You are correct that you cannot use a the typical rivet gun to install stanless steel rivets. They are two to three times stonger than aluminum. Most rivet guns have a disclaimer in small print somewhere on the package that says not to use it for stainless steel rivets. I destoyed one trying. It is also worth noting that you cannot buy a "real" rivet gun at any retail store incluing Home Depot, Lowes, Sears, West Marine or any other hardware or auto parts store, I looked. I bought a semi-heavy duty gun on eBay for about $20, that I have used for stainless steel rivets on a Sunfish boom. It worked OK, though I would like something with more leverage. However, I have used aluminum rivets for a mainsheet block on a Catalina boom. Yes they work themselves loose, but they will do the job for awhile then I just replace them. Next time I will use stainless.
It depends how they are made. I used an average Stanley brand rivet gun of the type you find in various hardware stores. It has done 304, 316 and monel rivets. The thing to look for is that the arms of the gun are made from top-hat section steel, and not cast alloy of whatever type it is they use. The cast ones break and the jaws often crack too.
I'm really not an expert aluminum fabricator, but my guess is that to get the benefit or a sleeve, you need to rivet it tight in as many places as possible, and that would be putting fangs through the vang, er, rivets.
I'll add some additional comments.
Monel rivets are the go, there are less corrosion issues with them then with any grade of stainless.
Using Tef-gel or Duralac will help prevent corrosion in the future.
I haven't through bolted any spare now for 20 years, in reality, there isn't the need as you'll aways be able to find a replacement top section.
With the end caps, the best way to remove them is push them out from the inside.
To do this with the plugs on the existing boom, either drop a large metal rod (10mm dia) down the hole for the gooseneck fitting or just simply cut the spar in half and knock them out that way.
With the top section being converted, there is no need to remove the end plug from the top as this will be the clew end of the boom, just cut the top section at the other end.
Never re-use the top section plugs for a top section, they will never re-seal properly and the spar will slowly fill up with water.
I've never had an issue with the cheaper rivet guns, including the cast ones. The air powered ones are nice and quick but and require no strength.
Youi cut the spar in half to push the endcap out?
While I did not cut my boom in half, I will agree that it was a lot of trouble to remove. Various mechanical means such as using pliers, drills and jig saws proved worthless. I ended up using a small blow torch and melting it off.
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