Seadoo and 14ft Jon marriage- jetjon

[64coupe]

Hi I am new to the site and wanted to introduce myself. I have been googling the idea of building a jetjon and found this site to be filled with a lot of great ideas and useful information. I have a few questions about the idea and I hope some of you can help answer them. After reading the other threads I hope to hear from PSG-1 lol.

I have researched this idea and have searched many members threads as well as their youtube videos.
I have a donor seadoo hull and a 1437 Fisher.
I would like to approach it similar to Painlesstom - https://www.tinboats.net/forum/viewtopic.php?f=21&t=28350 I will be cutting some of the rear seat out and placing the stick steer more up front with no console also a casting platform up front and a bow mount trolling motor. Anchor, battery and gear will be up front for weight balance.

Has anyone had luck in the long run with Resin/Fiberglass bonding to the aluminum? I will be setting the seadoo hull in the rear of the boat. With the exception of minimal to no fiberglass from the seadoo hull exposed underneath. Yes the engine will sit up higher and the pump tunnel is fiberglass. I just cannot see smacking a rock with the fiberglass seadoo hull. I would like to run the upper Delaware River out of Bucks County Pennsylvania.

I was wondering if the two different materials would seal better more permanent with a sheet of rubber? Sealing the two halves with a "gasket" and sealant (3M 5200??) I feel would be a more permanent seal. I know not lifelong but certainly more than a couple seasons. I would consider carriage bolts to fasten the two halves. I see the expansion rate of the aluminum to the fiberglass to be the biggest hurdle. https://www.rubbersheetroll.com/rubber-sheets.htm


Thanks everyone!

 

[64coupe]

Here is yesterdays beginning of the project.

 

[64coupe]

Thank you for moving this moderator.

 

[painlesstom]

I'll be keeping up with this, look forward to seeing how you do it all.

I wouldn't use a rubber gasket between the two hulls... it could be prone to shifting and if both surfaces are not flat, it wouldn't seal anyhow. Much better off to use a flexible sealant that will conform to the exact shape of both mating surfaces, that is what worked for me without issue anyhow. Even after bolting everything together and letting the polyurethane cure, there was still alot of flex. Laying in fiberglass to extend the footprint of the jet ski hull will reinforce the floor and protect the union between materials. With no flex, the joint would have the potential to last the life of the boat. I used Loctite PL S30

 

[64coupe]

excellent. thank you.

any reason you used the pl s30 loctite versus the 3m 5200?

 

[painlesstom]

It has a thicker texture which was easier for me to work with. I've used 5200 one time in the past and I remembered it wasn't that thick, flowed too easily for my liking. Didn't want to chance using it only it have it drip out of the joint and leave gaps. The Loctite S30 is like tar and peanut butter, I use it for several things I do on a regular basis and swear by it. Great product.

 

[64coupe]

I will give that some thought. Thanks again.
I hope to have the seadoo hull prepped this weekend and the transom, floor and seat marked for cutting.
btw the mokai is awesome!

 

[PSG-1]

Can't believe I missed this thread when it first came up. Sorry for the extremely late reply.

Anyhow, welcome to the board, and welcome to the hobby of jet john building. I've seen a lot of jet johns built the way you're describing, and indeed, they run just the same as the ones with bolt-in ducts. The question is, the expansion rate of aluminum vs. fiberglass as you described. I can't definitively say how well this type of setup will hold up over time.

Typically, you'll want to cut the opening in the boat, and then cut the hull out of the jet ski with the pump and motor mounting areas as one solid piece, and cut the fiberglass hull larger than the opening of your boat. Then the fiberglass hull is placed from the inside of the boat, bolted, and sealed.

As for how to secure it, this is not really my area of expertise, and it's why I didn't use this method to build my boat, as fiberglass isn't my thing, welding and machining is what I know. I would think you could do some glasswork to the cut edges, and beef them up, so you can drill mounting holes to secure it to the boat.

For sealant, 5200 is good stuff, but RTV ultra black is what's generally used to secure jet pumps to hulls, and it has a very strong bond, but not ridiculously strong like 5200.

Again, my expertise isn't in working with the fiberglass. But when you get into the engine, mechanical, electrical, etc, let me know, I'll be glad to give advice.

If you have any questions, e-mail me at PSG1Shooter@ REMOVETHIS gmail.com


Keep us posted on the progress, and be sure to post pics as it moves along!

 

[painlesstom]

64coupe » 30 Apr 2013, 19:20[/url]"]I will give that some thought. Thanks again.
I hope to have the seadoo hull prepped this weekend and the transom, floor and seat marked for cutting.
btw the mokai is awesome!

Thanks!

Have you made any progress? I came here hoping to see some new pictures.. lol


PSG-1, I thought you'd like to know my hull union has been performing flawlessly so far. I've put some good miles on the clock, approx 400 so far, with not one leak or hull issue, solid as a rock. So fiberglass/aluminum can work together if done right, not sure how much of a hit it could take though, I'm very careful about where I go so not something I'm worried about personally. Have you changed anything on yours lately, how has it been doing?

 

[PSG-1]

Mine's doing really well, I even got the diagnostic software for it! I have been considering adding on a spoon, like Ranchero did with his boat. It would be nice to take out that cavitation in chop. We've probably run 500+ miles on the rivers of northeast SC over the last couple of years. Check out my Aluma-Jet thread, I updated with some videos of local rivers, etc.

Glad to hear your boat is running good, and that the fiberglass-to-aluminum connection is properly working with no issues. That's good info for others looking to do the same type of build. As long as they do it the way you did yours, it ought to work just fine. Taking impact would be the only questionable thing, but, then again, that can be an issue with ANY boat, regardless...especially something like a rock.

 

[painlesstom]

Did you ever finish this project? Please tell me you have an awesome boat you want to share with us!

 

[64coupe]

Tom, I ended up finding a boat I wanted at the end of the season, sold the Fisher, and bought a Deep V Tracker. Since then I also picked up a Kawasaki Jet Mate that I swapped in a 750 engine. I still have the seadoo pump section and all the parts to do the Jet Jon. One day I'll get around to it.
Steve