Damage boat project

I think if you have the GT40 heads then you have the carbed version of the Pro Boss. I believe this was rated at 280HP.

I have also read that the HP difference between the Pro BOss Carb'd(280HP), Pro Boss TBI(300HP) and GT40 (310 HP) is likely just marketing and that the engines will all perform around the same when turned correctly. Not sure how accurate that is but the difference is small and really the condition of the engine will make a bigger difference.

It was also a efi engine but was taken off. So that would make it 310hp? Any idea what those rectangle blocks are for? I can just remove them?

tryathlete wrote: Mike, that's not a GT40 EFI. That engine was not available until 95. You've got the one many have converted to carb because of lack of availability of replacement parts. It was a Throttle Body injected engine. The GT40 is port injection.

Yup, and the TBI I believe was 300HP.

Mike9812121298 wrote: I got some work done on the hull, I did some more cuting and sanding last night. The strut mount looks pretty solid, the rudder mount I added some glue before I fiberglass to make that connection from when it ripped out of there. Next I'm going to sand down the glue to make it level and flat.

8122pbrainard wrote: Mike, I suggest going deeper into the cracks that are evident on both the inside and outside of the hull. By routing them out farther, you may be able to make sure there isn't any disbonding between the layers of glass.

Mike,
I don't feel you are following recommended procedure with the repair to the hull. As mentioned, you need to grind out the cracks more.

What is the "glue" you refer to? The gray colored stuff you applied? What is it?

I believe the iso-damp material on either side of the damage should be removed also. You then can overlay resin and fiberglass tapering out past the damage. When done it could be replaced making it easier replicating the original look.

http://www.westsystem.com/ss/assets/HowTo-Publications/Fiberglass-Boat-Repair-and-Maintenance.pdf

I'm not a boat builder and am excited about your project enough to keep reading every post on your thread. I've built Fiberglas kayaks and have repaired holes and done a little gel spraying --enough to know I didn't know much. Maybe this link will give you a little direction.

http://www.westsystem.com/ss/assets/HowTo-Publications/Fiberglass-Boat-Repair-and-Maintenance.pdf

Mike,
Now that you've had a chance to read our comments and suggestions, we'd love to get some feedback from yourself. That would help us better help you with the project.

Are you getting any guidance from a friend? Also, I'd sure like to know what the grey stuff is you used. Hopefully it's not Marinetex!

No I completely understand I don't want to want have to do it a second time. The adhesive was 3m 3532, its pretty strong stuff. I spent a long day out at Westport,wa on a fishing charter, so I'm gonna see what I can get done tonight. I'm gonna grind it down some more tonight. Basically I need to take it down to 1/4 inch thickness of the hull? Then just glass over 2 -4 inches?

Mike, 3M 3532 is marketed as a semi flexible urethane construction adhesive for bonding materials such as concrete, rubber, wood, glass, and some plastics.. I am no expert, but I believe the semi-flexible property is something you would want to avoid at all cost when reinforcing a high stress area. I question whether the structure will be compromised with a semi-flexible layer, or any layer with unlike properties, between layers of fiberglass.
I have restored several boats prior to my current project. Although they turned out nice cosmetically, I now know that none of them was done to highest standards with the proper materials due to inexperience and lack of knowledge. The most important thing I have learned here is to listen to the experts. There is an unmatched wealth of experience here and they are passionate about their craftsmanship. I have asked more questions than I care to revisit and the experts here have been patient and helpful (with a few head SMHs at my ideas) and have led me to the proper techniques and materials. If you take their advice you will reap the rewards.

Mike,
I just looked up 3M's 3532 and agree with what John states. This statement on McMaster's site is the concern "The thickest and most flexible structural adhesives, urethanes bond materials that expand and contract at different rates." Urethanes are fantastic adhesives but wrong for your hull repair. I'm very familiar with them since I was involved with an automation project using the Lord urethane equivalent for bonding metal components. For production, we were purchasing it in 55 gal. drums.

Now, I feel you are heading in the proper direction with taking the hull down more. You want to remove the gel in the bilge until you start to see some glass. You want the new glass to bond to the old glass and not the old bilge gel coat. I also feel strongly that you should grind out the cracks as previously mentioned. I'm still concerned about some lamination disbonding in the damaged area. Also, it's great you removed the iso-damp so you can get the repair over a larger area. Stay with traditional epoxy resins, fillers and glass.

I'm curious as to why you used the 3532. Is it a material you use at work? Did a friend recommend it?

I see you broke thru. Still in kibitzing mode here. Here's an idea - somehow clamp some plywood up to the bottom side of that hole pattern. Maybe use some of that glue temporarily. Transfer the hole pattern to the plywood with 1/8 in. holes.

Then take out the remnant of the damage entirely. Then start the layers from scratch & you can redrill after it is all cured. If you put some plastic sheet over the plywood, the resin won't stick to it. I think a totally virgin patch will be stronger because there are less interfaces.

Mike,
Thanks for the pictures since they do show the disbonding concern.

Chris's idea is a good one. with bolting a board and plastic on the bottom of the hull to act as a form. Fairing the bottom can be done latter. Prime the area with straight epoxy resin especially where you see the disbonding. Then mix in some filler such as Cabosil or milled glass. Putty knife that into the disbonded layers and any low areas such as where you went through the bottom. From there, you are ready to start laying in glass. Have you looked for glass yet?

BTW, I suggest not using any more of the urethane adhesive.

Gary S wrote: But if he would start laying thin layers of thin new mat, each one being larger than the last, it would end up much like plywood in it's strength.

Correct. That's the suggested plan after the low spots and disbonding are addressed with the prime of straight resin and then the filled resin. I'm not talking about filling the complete area with filled epoxy!!

As far as glass goes, biaxial is my recommendation. Yes on US Composites.

I'm just here to watch and learn. Projects like this is why I love this forum! I"m learning a ton on here!

Nice going Mike!