Wing damage and welding....

I know, I know, wings are designed for 'compression' only, and last season, probably after our one capsize, we might have damaged the wing. Or, some "helpful" soul helped us up the ramp and pushed too hard on the wing....
whatever.... such is life.

I knew last Fall when I packed the H18SX away that the short leg (the one whose foot sits on top of the outboard bolt) had a problem. Where it was welded to the long leg, there was a crack, likely from torqueing.

When I went to unpack the Hobie this last Weds, I saw that the short leg had fallen off! Yikes. Probably due to the fact that the tarpaulin had worked a bit loose, the leg punctured the tarpaulin, then the tarpaulin flapped around in the winter wind causing stress on the leg.... you can guess the rest.

I found the leg on the ground below. My buddy (who is the Club Bosun and runs RC) is an experienced MIG/TIG welder. Question - what is the best method of repair? My thoughts are that we place the leg in situ (that is swing the wing down so the foot of the leg is resting where it should, thus maintaining the proper alignment) then tack-weld the head of the leg in place. Then pivot/raise the wing so we can work on it, and complete the welding, and install a triangle (of Aluminium plate) as a gusset for added strength.

When he looked at it, he said the wings were powder coated, not anodized. Anyone know which?

Suggestions welcome.... SRM, Matt B, anyone?

_________________
2015 H16, with spin,
SOLD 1989 Hobie SX18 Sail # 1947 "In Theory..."
'Only two things are infinite, the universe, and human stupidity. But I'm not sure about the former.'

Sounds like an appropriate repair method. Adding a gusset will definitely strengthen the weld joint. In fact, would add gussets to all of the support leg joints.

Wings are anodized. They will need to sand off the anodize before welding. I would probably just shoot the weld area with some flat black spray paint afterwards and be done with it.

sm

you will have to clean any coating off the aluminum. in fact, you may need to grind into it some to get to really clean metal. your welder should know what to do.
they are probably junk and i would just send them to me.
Seriously though, they can be fixed by an experienced welder. from what i understand though, the tubes are hardened and should be treated as such. I know some have added a cross-brace to absorb stress.

John, that's awful! Sorry to hear about your wings, hopefully the repair isn't too bad. I am curious to hear how it goes, though.

I never got around to installing my wings last year, for the same reason. I had the starboard wing fit and was working on the port wing when I noticed that three of the four struts were cracking at the welds, probably at least 50% at each. I put them aside for some other time. I was planning on looking into weld repairs this year to see what the cost would be. I think that, rather than grinding or gouging out the welds, it may be easier to remove the struts, grind off the anodization and re-weld them. This may allow me to kill two birds with one stone, as the port wing really wasn't fitting up well - on the aft leg, the strut was at least .5" too short, and the forward leg seemed to have been installed a little "twisted" - the leg was very tight to the crossbar and more outboard than it should have been. If I have the legs removed and re-fit with the struts with the wing on the boat, it may allow me to improve the fit. Still trying to weigh the time, effort & cost against the convenience of the wings

I assume the struts were just standard aluminum pipe or tubing, maybe 3/4" or 1" schedule 40 6061 aluminum? Anyone know? Anyone tried it before? I like srm's spray paint idea, that would be my preference, lol.

I'm curious about your gusset idea... it seems that the problem is the fore/aft forces on the wing, but the only way to get a gusset on there would be in the transverse direction. A little extra stiffening at that point doesn't hurt though, I suppose.

_________________
Mike

'79 H18 standard 'Rocketman II' sail #14921 RIP
'78 H18 (unnamed) sail #14921
'08 H16 sail #114312
'97 H21SC sail #238

Years ago before hobie recalled the early SX wings a sailing friend has two of the struts break off exactly has John describes. Bob had it fixed exactly as John is think with a also triangle welded between the strut and the arm. He also did it to the two unbroken one as well and they are still doing well as I see the boat every year at one of the regattas in Nebraska. Mine broke after his but was covered under the SX wing recall where the replaced the broken strut and arm took the rest of them apart on pounded some type of slug down the arm and put everything back together and added the secondary strut at the stern to keep the wings from moving fore and aft.

_________________
2001 H18 w/SX wings & spinnaker #16740 (purchased new)
1989 H18 w/SX wings #14565 (purchased new, sold 2000)
Would buy another if Hobie would build it.

I am on deadline for a corporate matter (yes, I am a CPA), and there is more that I want to contribute, but not now, guys.

later

_________________
2015 H16, with spin,
SOLD 1989 Hobie SX18 Sail # 1947 "In Theory..."
'Only two things are infinite, the universe, and human stupidity. But I'm not sure about the former.'

The 'short' legs on the SX wings are vulnerable to damage....
The first thing that Hobie did was to insert a bar inside the leg as a stiffener.
That adds a lot of strength and stiffness.
The second thing was to add a 'retaining rod' which affixes (from the wing) to the lip of the hull behind the rear cross bar.
This retaining rod prevents the wings from folding forward if you pitchpole while sitting on the wing or hiking from the wing.
Yup, sailors will drive their Hobie cats pretty hard.

The geometry of placing a set of wings is a challenge.... and involves moving the studs around until "it works."
Start with mounting the studs in the cross bar tracks approximately where you want them to be...
mount the wings on the studs, then drop them gently so that the foot of the short leg is sitting directly on top of the outboard bolt. Then adjust the location of the studs to match, and tighten down the studs. Then match the tabs and insert the clevis pins and attach the retaining rods. We are also assuming that the H18 is "square" and that the cross bar tolerances are within spec.

Years ago, I was the Controller of a metal fab shop (MIG/TIG, Alum & Mag) and part of the production was tube welding. I was told that it is a real trick to keep the structure 'straight' while welding, as the heat may cause dimensional distortion. Hobie has done a great job in building this tricky product. Who knows what previous owners did to their boats and the wings. I am going to be super careful when it comes to volunteers helping me out of the water.....

_________________
2015 H16, with spin,
SOLD 1989 Hobie SX18 Sail # 1947 "In Theory..."
'Only two things are infinite, the universe, and human stupidity. But I'm not sure about the former.'

Repair worked like a dream.

Broken area was sanded, cleaned with spirits (Varsol), wing strut mounted in place, and tack welded.
Then we removed the wing, and took the entire wing inside the Club workshop as the wind was playing havoc with the TIG welding. Twelve minutes later, everything was properly welded EXCEPT that Andrew found a small crack in the tube. Out with the drill, and the 1/64th bit, one hole at the top and one at the bottom of the crack and all is good.

We refitted the wings, and we are ready to sail. I'll do the black painting when it's not windy.

Andrew brought with a piece of 3/8th " plate, instead of 1/8th" plate, so no gussets were cut and welded on. I'll do that at the end of the season.

thanks to all for your help.

_________________
2015 H16, with spin,
SOLD 1989 Hobie SX18 Sail # 1947 "In Theory..."
'Only two things are infinite, the universe, and human stupidity. But I'm not sure about the former.'

That's great news! Congrats on the successful repairs!

The crack in the tube, that's in the seat itself? That's a little disheartening. Hopefully it's small enough that it doesn't affect the strength of the wing too badly.

The weld shop I contacted estimated $20-$40 per leg. It seems that both aft leg struts will need to be re-welded. Just gotta get the boat back together and get it over there!

Happy sailing!

Crack was a very thin/small stress crack in the strut, perhaps 1" long.
My welder had very good eyes to spot this problem.

His 'minimum fee' to set up was CAD$60, and another $18 to do the weld.
Plus I'll buy him a beer next race night.

_________________
2015 H16, with spin,
SOLD 1989 Hobie SX18 Sail # 1947 "In Theory..."
'Only two things are infinite, the universe, and human stupidity. But I'm not sure about the former.'

Any thoughts on replacing the cracked strut? I measured mine to be I think 1" tube with what seemed to be 3/16" wall thickness. I figure it's gotta be 6061 aluminum. The material can't be too pricy, so it's just a matter of cutting it to size, shaping it to fit, lining it up and welding it. Of course, if it's really just a small rack, it'll probably last you a few years before really needing to be replaced.

I'll be in a wheelchair before that strut needs replacing....
Yes, it looks like T6061, and the dimensions sound good.
However, this will be a fiddly job.

Good Club racing last night, light winds, 6 - 8k, great weather.
Good to get back on the water.

_________________
2015 H16, with spin,
SOLD 1989 Hobie SX18 Sail # 1947 "In Theory..."
'Only two things are infinite, the universe, and human stupidity. But I'm not sure about the former.'