Twin I/O to Twin Outboard Conversion Project

What are all the holes for?

 

For the goodness of mankind . . .

Actually, they are for ease-of-access . . . similar to the other 'web holes' that I made.

 

Thats gonna be a crazy layup process...

When we did a stern extension similar to that we did the outer portion in a solid layup then did pre lam panels that got cut and then tabbed in. Doing all those shapes in place is gonna be a lot of layups, lots of peel ply and sanding and a lot of assistance in the layup.

Doable, but that is a complex hand layup.

 

Yes . . . probably why folks go with aluminum brackets

 

Yeah... you'd be about done except bolting it on and paint in aluminum.

But... electrolysis, noisy... bolts, surface finish never seems to be the same etc...

All just trade offs.

 

I’d just cutout after.

 

TP,

Great progress!
The web holes are already cut out right?
( I'm not sure why you're still getting counter advice, they're already cut out. That was your choice. )
Are you going to radius them with a router?
Full bull-nosing would allow for max radius and greatest ease of covering when glassing.

 

Yes, today is router day. I have a 1/2" bullnose bit and a hand router. (hopefully with a steady hand )

For me it was a trade-off . . . more challenging glassing vs. more difficult cutting. Perhaps one of the short-comings of a 'design-as-you-go' process.

 

Sanding in a variety of ways proved to be better than the hand router. . . but the rounding of corners is done.

I have what perhaps is a unique method for glassing. . . (see illustration)

I use 0.7 mil plastic sheeting as an outer layer, peel ply if needed, then the glass (CSM or cloth). I then apply resin to the cloth/CSM and the substrate. Then pick up the entire thing via the plastic sheeting and apply the resin soaked glass to the piece.

The resin, now on the inside, works the air out of the glass as it wets from the inside out. I can work the wetted glass as needed by rolling over the plastic. The tools stay clean because they don't come in direct contact with the resin.
.

 

Not really unique, I and a lot of others I'm sure do variations on the technique, really shines for laying down tabbing in corners over a fillet, especially with biaxial fabric.

 

1708 is harder to wetout than most glass .. the way you drew it, I only see resin on one side; I usually work both sides with resin.

 

The key aspect of the technique (IMO) is that resin soaks from the '08' side to the '17xx' side, forcing air out of the cloth as it soaks through the fabric. When people add resin to the outer side in a fairly dry state, it has the tendency to trap air in the cloth that has to be worked out. Some folks do this better than others . . .

The benefits that I have realized from the technique are . . .

• Better wet-out of the cloth
• Quicker application of the glass
• Less fumes, mess, etc.

 

Next steps in the building of the extension pod . . .

1) Fillets and more fillets . . . (I have some milled glass to make the fillet compound . . . I will be mixing with VE resin. I am also thinking of using the Coosa dust (from cutting scrap boards) as an additional filler to mix in. Thoughts?

2) I have been taking 10 years of anti-fouling paint off of the transom . . . 5 applications of paint remover so far . . . it is almost there. Then I'll be doing some sanding to get the last bits. The hull appears to have been barrier coated.

3) Once cleaned-up, I plan on marking and cutting the access holes in the boat's transom and underside of the swim deck. My plan is to put the Extension pod in its current 'framed' state in set place at the transom and use the openings (2 at the transom and 4 at the swim deck underside) to trace the cutouts . . . making a nearly perfect match of the mating surfaces. I thought about using a large paper template of the cutouts instead, but I figure the actual extension pod as the template will be the most accurate. Thoughts?

4) Wondering if I should re-coat the transom with barrier coat (Interlux EP2000) after sanding or just go with the sanded gelcoat as the transom surface for the adhesive chalk (4200/5200). Also, what would be best to seal the extension pod to the transom (4200 or 5200?)

T.I.A. for thoughts, ideas, and comments.

 

I'd try a sample of the coosa dust and decide from there. My only experience is wood related and sawdust per se is not that good a filler, a little too grainy. Sanding dust is better, almost as good as purchased wood flour.

 

Both sawdust and milled fiber really offer little for fillets. First of all, the strength added is negligible compared to the glass and this is sort of intuitive. Second, the fibers or sawdust or cotton all tend to make fillets less than smooth and offer the chance for air and ugly work.

I always only use cabosil in fillets. Cabosil has its own issue as a filler; it and the resin get hard as nails, so I always fillet just before applying tapes wet on wet.