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Hobie 17 wing tube diameter and thickness (corrosion repair)
http://www.hobie.com/forums/viewtopic.php?f=15&t=36436		 Page 1 of 2
Author:  NAHCA555 [ Mon Jun 27, 2011 10:57 pm ]
Post subject:  Hobie 17 wing tube diameter and thickness (corrosion repair)
I recently bought a H-17, thought it was clean, but I just found a severly corroded spot at the insert line on one wing. There was a sticker around the spot... thought it was the insert mark, and maybe it was, but it was hiding the corrosion.

My idea is to get the same OD size tubing with a much thicker wall. I'll turn 3"-4" down to fit inside the factory tubing, either as just a sleeve, or replace the whole lower 16" straight section (with a sleeve inside the stock tube) and rivet it on.

I'd prefer no welding, as I believe these were heat treated tube sets... I extended a spinaker pole this way on an SX 18 and it works well to this day.

Anyone know the tubing spec's? Anyone done something like this before?

Brian
Author:  mmiller [ Tue Jun 28, 2011 9:31 am ]
Post subject:  Re: Hobie 17 wing tube diameter and thickness (corrosion rep
1.875" OD x .083 Wall
Author:  divimon2000 [ Tue Jun 28, 2011 12:41 pm ]
Post subject:  Re: Hobie 17 wing tube diameter and thickness (corrosion rep
And I agree with your plan, don't weld! As you know, be tight as you can with the sleeve (a pain to get in tho).
Author:  NAHCA555 [ Tue Jun 28, 2011 7:11 pm ]
Post subject:  Re: Hobie 17 wing tube diameter and thickness (corrosion rep
Thanks Matt and divimon2000 :-)
Author:  divimon2000 [ Wed Jun 29, 2011 6:02 am ]
Post subject:  Re: Hobie 17 wing tube diameter and thickness (corrosion rep
NP. I would probably keep the tube foot (not cut and replace) since *I think* it'll be stronger with the sleeve- not as much pivot point. I did exactly that to a sunfish boom after someone tried to weld it (the weld material was solid, but the alum tube next to it was trashed from melting, and as you said de-tempering.

You'll love the boat single or with another smaller person. So easy to sail. I pull it out when I'm in for fun but not so much work (as my 18).
Author:  srm [ Wed Jun 29, 2011 8:20 am ]
Post subject:  Re: Hobie 17 wing tube diameter and thickness (corrosion rep
NAHCA555 wrote:
Anyone done something like this before?


Yes I installed internal sleeves in the wings of my prior 17 and may do it again on my new boat because the tubes are starting to corrode. The last time I used a schedule 40 aluminim pipe. It was overkill, but it was the best I could find from McMaster Carr. A 1/16" wall tube should provide plenty of support. Cut the sleeves about 12" long and insert so they are centered at the deck line.

Before you can install the sleeves, you have to remove two foam plugs and a piece of wood that is installed in the tube. The wood is most likely water logged and can be a pain to get out. I used a long lag bolt screwed into the wood to pull it out.

To install the sleeve, I coated it in epoxy, slid it in the tube to the proper depth, and let the epoxy cure.

sm
Author:  NAHCA555 [ Thu Jun 30, 2011 10:25 pm ]
Post subject:  Re: Hobie 17 wing tube diameter and thickness (corrosion rep
Thanks srm,

Yes, I've been looking for a way to do a really cool total replacement of the insert/straight portion without welding... but I cannot find the 1-7/8" (1.875")OD tubing by .120 wall... or thicker. All I can find is .060 wall... not even as thick as the original tubing, and I need it twice as thick, with same OD.

I was goint to turn it down to slip inside, leaving the straight part original diameter. I would just cut the wing off above the deck line and insert the now turnd down insert section into the wing... but alas... the tubing i need so far does not exist.

I will be looking at your method srm of sleeving the deck line area... thanks for the heads up on what's inside the tubing.
Author:  srm [ Fri Jul 01, 2011 5:39 am ]
Post subject:  Re: Hobie 17 wing tube diameter and thickness (corrosion rep
Check out 1-1/2" Sch 40 Aluminum Pipe (not tube). It is 1.9 OD with a .145" wall. So very close to what you're looking for.

However, I think doing a sleeve would be the preferred method of repair. There is a lot of stress on those tubes, so cutting and splicing could lead to structural issues. Also, any misalignment of the new tube section could result in problems installing the wings into the boat. Not to mention that cutting, machining, and splicing in a new tube section would be a lot of work.

Installing an internal sleeve is a relatively quick and easy way to make the wing stronger with no chance of altering the tube geometry.

Unfortunatley, the wing tubes often tend to pit and corrode right at the deck line. I think this happens because this is right where the wooden reinforcement and plugs are located. Any water that gets in the tube eventually leaks past the plugs and soaks into the wood (the plugs are just pieces of soft foam). So the tube is constantly wet in this area, and if you sail in salt water, then the salt water eventually eats away the aluminum. A bit of a poor design IMO.

sm
Author:  NAHCA555 [ Fri Jul 01, 2011 11:20 pm ]
Post subject:  Re: Hobie 17 wing tube diameter and thickness (corrosion rep
SM,

Thanks again, will be looking to locate some of that AL pipe locally. I also have a lead on a very cheap H-17... it has an aluminum trailer and if the wings and mast are good, heck it would be worth it to pick it up just for parts!
Author:  Chris Voith [ Wed Jul 06, 2011 4:56 am ]
Post subject:  Re: Hobie 17 wing tube diameter and thickness (corrosion rep
I measure the ID at 1.6875" (1-11/16"). Will 1-1/4 sched 40 pipe work?
specs here:

http://anywhoyp.yellowpages.com/busines ... metals.com
Author:  srm [ Wed Jul 06, 2011 5:33 am ]
Post subject:  Re: Hobie 17 wing tube diameter and thickness (corrosion rep
I would use 1-1/4" Sch 10 pipe, not Sch 40. It has the same OD (1.66"), but thinner wall. Even the Sch 10 is a thicker wall than the original tube, so it's overkill, but I haven't been able to find anything thinner that would work. You can get a 3 foot length from McMaster Carr for about $30.

sm
Author:  divimon2000 [ Wed Jul 06, 2011 7:02 am ]
Post subject:  Re: Hobie 17 wing tube diameter and thickness (corrosion rep
I would get that for parts! Hard to find 17 stuff anywhere.
Author:  Chris Voith [ Fri Jul 08, 2011 2:26 pm ]
Post subject:  Re: Hobie 17 wing tube diameter and thickness (corrosion rep
I was surprised to find how short the wood piece is, though glad it wasn't any bigger than 6". They were a bear to get out... had to basically shred 2 of them to get them loose enough to extract with a lag bolt. Many implements of destruction (and bad words) were used in the process. Got a 6' sch 10 AL pipe from McMaster-Carr for $63 and did all 4 legs w/ 18" sections.
Author:  NAHCA555 [ Sat Jul 09, 2011 11:37 pm ]
Post subject:  Re: Hobie 17 wing tube - inserts?
Interesting, the wood inserts. I know the SX wings originally had wood block inserts, but later changed to these 1/4" thick x like 12" long flat aluminum pieces driven in past the weld point of the support bar.

I just checked my set of H-17 wings tonight and mine do not have any wood inserted into them??! I wonder if this was also an abandoned method after a while?

I like the flat bar idea, but on an SX distortion was a non-issue... on a 17 wing you'd have to be real careful not to out-of-round the tubing... Apparently some 17 wings had no extra support?...

Ya know, if these were made out of carbon tubing corrosion/strength would probably be a non-issue! :mrgreen: :lol:
Author:  Chris Voith [ Wed Jul 27, 2011 2:53 pm ]
Post subject:  Re: Hobie 17 wing tube diameter and thickness (corrosion rep
Having sailed this boat a few times since making this repair, there's a subtle but definitely better feel to it. Sailing in chop always made me wanna "sit light" on the wings for fear of trashing them. Together with the other advice on this forum about tightening things up, there's a huge difference over when I bought this boat... end caps, reseat xbars, Dyneema lacing on the tramp (replacing bungie cord!), took some slop out of the rigging and finally these wing reinforcements... it seems like a different boat.
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