Hobie 16 flex again - epoxy vs a second bolt?

I am new to this forum and want to thank everyone for all the tips!

I have an '86 Hobie 16 with what I believe is more than a 'normal' amount of flex between the hulls caused by the loose corner casting fittings. The front and rear crossbar entry points seem tightly coupled to the corner castings when observed as I move one of the hulls up and down. I have tried all the home remedies, shims, tight tramp, ignoring it, etc.. I am considering epoxy as the ultimate solution, but that feels a little too permanent.

It seems to me that part of the problem is caused by rotation of the corner casting around the single bolt used to affix the casting to the pylon. If a second bolt hole was drilled through the casting and pylon directly above/below the primary bolt, this rotation would be eliminated.

Anyone ever consider this type of repair? Any concerns about stress fracturing the corner casting, violating one design specs, properly sizing the second bolt, etc.?

Thanks in advance for the sage advice.

I don't think another bolt is going to do the trick. Here is what I did.

I used west marine epoxy, glued all the corner castings to the uprights out of the hulls. the 4 horizontal pieces into the corner castings were still tight, with the glued corner castings, you can still remove the front and rear cross pieces, the sides will be permanent, depending on what you consider permanent of course.

I poured the epoxy with the boat in an upright position, everything tensioned and squared and flat. Remove the castings and clean everything to start. From inside the castings, drill 4 holes in circumference around the inside edge angled slightly out, these will be your pour holes, 5/16" bit. When the castings are on the uprights, you want to be able to see the crack between the casting and upright through the drilled holes.

I put foam inside the uprights, with a small air hole, just cause. Get your silicone out, seal the rear track at the top of the upright so you don't have to fill the track with epoxy. So you assy everything, flat and square, tension the fore and cross bars with straps if you feel the need. Get your silicone out, seal around the bottom of the casting, the bolt holes (you can redrill these later, just don't want stuff leaking out), the rear track should be already sealed or seal it at the bottom of you forgot to do it at the top, the foam inside at the top of upright will keep any epoxy out of the inside but shouldn't be too much of a factor.

Go down to wally world and get some of the cheap catsup/mustard bottles to pour into the casting holes. I mixed about 1/2 a bottle at a time, the stuff is runny enough it will fill any voids and run out anywhere you forgot to silicone. From the top through the holes you will see the cracks between the upright and casting to fill easy enough. Go around and around and fill all 4 corners and let set up. You can silicone the holes when finished.

You will have a stiffy everyone will be envious of, guaranteed. And a whole different boat!

Note: the rear channel on the uprights needs to be completely sealed with silicone to prevent 'leakage'.

Man! I wish you took pics or a video of the process.... So many older 80's boats would certainly benefit from this!

_________________
Tim Grover

Memphis, TN fleet 134
Hobie 20! G-Cat5.0 and 2 Hobie 14's
Photobucket now wants $100 to post pics on forums......... pass.

The boat gets sloppy because the pylons and castings wear over time increasing the clearance between these parts. Adding another bolt isn't going to tighten things up. You need to fill the gap between the pylons, crossbars, and corner castings.

The best product I have seen for this is West Six10 epoxy adhesive. It is a pre-thickened resin that comes with a static mixing tip and can be dispensed using a caulk gun. Mask off the crossbars and pylons first. You can also apply a coating of release agent to them before epoxing to make future disassembly possible. Then apply a coating of the Six10 to the ends of the crossbars and pylons and to the inside of the corner castings. Re-assemble the boat and wipe away the excess resin. Install and tighten the tramp as well as the crossbar rivets and bolts. Remove the masking tape and let the epoxy cure. After a day or so, the boat should be very stiff.

sm

It's really pretty easy, took more time to figure out what I was going to do. I chose not to go the route others used in using thicker epoxy and assy, this tends to scrape the epoxy off upon assy though it should be an improvement. The prep time of making sure everything is square and flat takes some time, using a laser level might be useful here. You want the regular runny epoxy otherwise it will take forever and you won't fill all the voids. I would bet doing what I have described will net a stiffer boat than new. If I remember right, raising one bow more than 1.5" tends to be a strain while on the trailer. Once on the water there is very little movement if any and the ride is smooooth. Mine is '84 btw.

Thanks for the feedback, the extra bolt was a hopeful idea.

srm - I am curious about the epoxy release agent. What is it, where to get it, how to apply, does it work?

MarkB - Top filling is an option I had not heard before.

Has anyone filled from the bottom? I was considering removing the running rigging, turning the assembled hull/frame/tramp upside down (with tramp tight), ensure square and level, and fill the casting/pylon connection from the bottom, leaving out the epoxy filler some recommend to make sure it runs into all crevices. Just pour into the seam between pylon and casting and continue to fill until it doesn't take any more. Leave the front/rear cross bar joints dry unless rig is still not tight enough, and leave the side bars dry since they aren't part of the rotating structure. Is disassembly and pre-coating with epoxy important to get all surfaces coated?

Thanks again for help.

I squared mine using diagonals from the bridle attachment points at the front and the shroud attachment anchors on the hulls, figuring the boat didn't care where the sterns or tramp were located, though I did level horizontally both sterns as pairs and then bows as pairs. Hadn't thought to pour from the bottom but that is a thought. Also used the cheap dollies from harbor freight to set the hull on, makes moving them around easier once the tramp is assembled.

There are countless release agents you can use. Most are applied either by spraying or by applying by hand (similar to waxing a car).

http://www.uscomposites.com/moldrelease.html

Personally I would go with the thickened resin approach applied to the pylons and castings with the boat disassembled and then assemble the boat, square it up, and let it cure. It is more or less a proven method.

sm

Gary Willcox wrote a good illustrated article in On The Wire Vol 3 - Issue 1, October 1998:

Hobie 16 Frame Epoxy Project Increasing the Performance of Your Boat

http://www.thebeachcats.com/OnTheWire/wwwcatsail/archives/v3-i2/feature1.htm


I followed his process several years ago on my 1982 and recently on 1984 H16s while they were on the trailer. I waited until after the epoxy cured before I re-installed the tramp and also used the Marson VHR-2 to pull the rivets.

While removing one of the nuts on the dolphin striker bar of my 1982 H16, the bar broke before the nut turned. Thankfully there was still enough thread left on the bar that I was able later to thread a new nut on it's end. I also had to replace a rear corner casting and rear crossbar on that boat since the casting had a crack in it and had corroded tightly to the rear crossbar. The other end of the old rear crossbar was almost paper thin (where it had been in the other side's rear casting). Fortunately, I was able to get a good used rear crossbar and rear casting locally from Pat Martin's Starboard Marine in Panama City Beach, FL.


I agree with what Gary Willcox said after completing his project:

_________________
Tim
84 H16
82 H16
87 H14T
Tortola Sails: 115222
Blue Prism Sails: 88863
Clearwater, FL

I epoxied my 86' with the help of a friend. It made a HUGE difference, especially in the ocean or choppy water. It's like getting a new boat. I could be wrong, but I think setting it up slightly toed out is what is recommended. I'd have to double check though, so don't quote me on it.

_________________
James
86' Redline Hobie 16
Sail # 76909

I had the thought of 'repurposing' those older boats. Like Factory Five did with the Cobra replica/mustang drivetrain and now the 818/Subaru stuff. If someone could design modern hulls that would accept the H16 parts and produce them at a reasonable cost I think that would be a smash! Some real nice wave piercing bows with buoyancy. Maybe Hobie will look into this. Be a good way to get into sailing at a reasonable cost with plentiful used parts.