I am in process of re-tubing my 5.4, and would like to get input on how to create the joint around the transom. On my boat, it looks like there is a reinforcement patch on the tube in the general area, a hinge strip connecting the top of the transom with the tube (made of rubrail?) a flange strip over the outside flange, a mysterious L-strip on the inner corner (item 2 in the attached sketch) and a finish patch over the whole thing. As my old tubes look like they were glued on again and again, and have copious amounts of sikaflex, I would like to know how these should be attached, and how to make the L-strip on the inside corner.
Are you using new tubes from Avon? If so they do include the patches to install. It will just be a different style than your boat most likely came with. They used ot have a big molded rubber "bracket" that glued ot the transom under the tube but that is no longer the case.
Unfortunately my tubes did not come with pre-cut fitting strips. I have ample hypalon so I am planning on cutting strips to fit, and the only thing I can think of is darting these strips to enable them to fit the curvature.
I have glued the tubes to the boat yesterday, but still haven't bonded the underside strips or any of the transom reinforcements. My plan right now is to glue pretty much as I sketched out in the second pdf, except that I would make the inside L-piece with a lot of darts to allow the hypalon to conform.
Photos would be great.
I will also post some pictures of my progress.
As I have had a hard time finding any pictures on here of re-tubing (with the exception of the sweet super-student project), I thought I would post some photos of my experience. This is the first time I am doing it, so I am sure there are many improvements and better ways to do things. I intend this to be a basis for suggestions and hope it may help others who will be going through it in the future.
I got my tubes from Paul at Tidel, and he has been quite helpful, as well as ribraff, who was kind enough to send me his very detailed instructional booklet.
Here are some photos:
1. Tubes arrived from England!
2-4. Inflated tubes placed on the boat mostly as a morale-boost.
One thing to note is when we traced the flanges onto the tubes for the first time, I almost began to sand the bond area only noticing at the very last minute that we had actually marked them upside-down. It's hard to tell on the old school seariders, but there is in fact a tiny little bit of rake to the tubes, so they have an up and a down-side...
When I removed the old tubes, I noticed that the flange on my hull was badly damaged and there was quite a bit of delamination between the hull and the deck through the flange. I used a grinder with a flapper wheel to remove damaged material and scarf/expose about 50mm of good material on the hull and deck side of the flange. Then I taped some cardboard underneath the nose and used thickened resin to create a smooth surface for topside lamination. When this was cured and shaped, I removed the cardboard caul, faired the bottom and added another 3 layers from underneath to tie it together. All together, I used about 6 or 7 layers of 600g/m^2 Biax and used polyester laminating resin. The photo shows the filler on the caul plate. The joint between the hull and deck can be seen in the middle of the exposed laminate.
The first step after repairing the hull and sanding the hull flanges for bonding was to template and cut all of the bonding strips. Paul supplied a few yards of Hypalon to be used for strips, and we simply traced the old strips onto the material. It proved to be a bit of a puzzle, as some of the strip require to be placed on the bias, and others don't, but we had enough material available to make it all fit. The photo shows my friends Sam and Aaron sanding the strips before cutting them which is a lot easier when using random orbital sanders.
Once the strips were sanded and cut, I brought the C-strip to a local sailmaker to get it sewn as seen in the third picture. The instructions I had called for double sided tape, and Paul suggested placing this strip differently to prevent sand from getting into the joint, but I was pretty keen to replace the tubes in the same way they were originally installed, so I decided to do it this way. It worked out well, and the strip laid down really well. The strips near the nose are on the bias, which helps the material shear and stretch along the curved outline.