What about the aluminum extrusion having a flat bottom while the hull is curved?

Gary

You can buy similar products from pointnorth.co.uk, as they are not boat people they are a bit cheaper
stock number lb3 £1.30 for stainless
stock number lb2 £0.10 for plastic

http://www.profabrics.co.uk/shop/show_product_info.php?id=LB2
http://www.profabrics.co.uk/shop/show_product_info.php?id=LB3

Never used them so I can't vouch for how suitable they are.

Gareth

Well, if you are filling the existing groove, nothing prevents flattening the top so the C profile lies flat. Also most C profile are designed to be put on curved masts anyway....

Pepin,
I agree that using C track would be simpler and cleaner. I'd like to avoid fussing around each loop or slug when filling/glassing/painting. Are there differing grades/strengths of C track? I have some on Flight Risk that's been opening up, leaving me with the same problem I currently have on the Stealth. I have some old pieces off a SC20 that are pretty heavy, but dealing with Aquarius is unattractive. Sources for the track/channel/extrusion?
Thanks guys, I'm getting more optimistic....

Dave

Try Sunrise Yacht Products in St. Pete. They make great tramps and used to have a ton of different C track designs on their website. I could not find the tracks today but they are great people to deal with. Give them a call.

Sunrise Yacht Products

Sunrise Yacht Product C track page

What an awesome resource you guys are!

Dave

The answers to your problem are getting complicated.

Do you have a good sailmaker in your area? Ask them. I have had similiar problems and the sailmaker fixed them. My sailmakers solution was to replace the cheap poly line used for the boltrope with a quality solid braid. In only one case, I think we went with a larger line.

Try the simple, cheap, light solution first

Carl,
I agree the the proposed solutions are getting complex, but I think Gary's correct in pointing out that the channel molded into the hull is flexing, and I think that this is what's allowing the bolt rope to escape, not that the bolt rope is shrinking in dia. I have this issue on another boat, and I increased the bolt rope dia, and the channel just opened up more. But I do need to inspect the channel closely to see if I can confirm that the groove is indeed opening under pressure. Thanks for your input!

Dave

Following Gary's post I thought I'd check on my older boat. Having pulled the tramp off, I used a very bright torch to shine through the slot onto the inside of the track. Having thoroughly inspected both sides, I found a short crack (about 7" long) that had been repaired previously and was now ok - all of the rest of that port track and the entire starboard track were undamaged. I checked the integrity of the repaired crack by trying it with the blade of a penknife and I couldn't even get the tip in (I could have if I forced it, but you get the idea). I'm therefore perfectly content that enlarging the bolt rope was the correct solution and that the crack (repaired by a previous owner) was not contributing to the problem I was experiencing - especially as my tramp tended to pull out of the aft section of the starboard track!

Carl's right - I think you should look at the simpler solutions first................

Just to let readers of this thread know, Stealth produced very few boats with the embedded tramp track, John found it to time consuming to build and reverted back to the original idea of attachment points on top of the hull.

I would ask John P directly if he put the Delron strip in the top of the hull that the rivets bind into as my instinct would say that he probably didn't, having gone to the idea of a track.

Ok, I checked out the grooves with good illumination and a larger screwdriver. The stbd hull's groove is cracked nearly three quarters of its length. Gary did indeed make a good effort to open the crack and epoxy it, but it has broken open again. A smaller(shorter) crack is visible in the port hull, which hasn't been repaired. I really don't think I can easily and sufficiently reinforce this groove to the point that it will reliably hold in a bolt rope. When I pry gently with the screwdriver, I can see the cracks open up, as well as noticible flexing of the hulls in the vicinity of the groove. In my opinion, any successful repair of this design would need to occur from the inside, which seems substantially more work.
I found a couple of lengths of alum C channel from a SC20 that seem stout enough to stand up to the loads. I'm currently drawn to attaching these to a filled and glassed over groove. So unless someone here talks me into something else, my next questions are:
If I fill the groove with West high densitity filler and tape over the groove, would that be solid enough to attach the track with #10 x 1" self tapping screws? (I expect to epoxy the track down as well). Or should I embed nuts in the groove when filling? If so, I'm gonna have to locate them accurately, probably with the track and some bolts. What can I spray/coat the screws with to insure that they'll release from the epoxy?
Thanks for all the input guys, my thinking has gone thru a fair evolution since the beginning of this thread. I'm excited to beef this boat up enough to stand up to the abuse I'm sure to give it.

Dave

Embedded nuts seems like a lot of fiddly work. Why not burying in the epoxy a stainless strip with machine screws affixed at regular interval? Once the epoxy cures you will have a long row of screws sticking out of the hull, ready to attach your C track to it with small nuts (just wax and tape the threads to prevent epoxy from sticking on it).

The inconvenient of this method is that you cannot make the nuts flush with the hull, mmm...

I would have got the "magic mushrooms" you linked to earlier and used those with a backing plate epoxied inside the tube.
Marstrøm is pretty expensive but there has to be other suppliers.

Can't do that, those would be at the wrong angle if screwed to the filed tube. Mushrooms need to be fixed perpendicular to the trampoline plane.

Pepin's right, the groove is on the inside of the deck, which is rolling down towards vertical. The mushrooms would be at a bad angle. I like the stainless strip idea though. If I could install it in the bottom of the groove, in the same plane as the deck I could even drill and tap after all the epoxy work and paint were done. This is getting more elegant men....

Dave

Would sail slugs parhaps work for you? That's the way my rear lacing is attached to the tramp on my Nacra 5.2. I'd bet they'd only pull out if the whole track ever separated.

[edited for typo]