Thread:

Addictor 333 Mini OB boat to 110hp Jet Boat Conversion

BoatPI- The XP was such a good fit for my project. It's a lightweight powerplant, yet still very powerful. The motor/pump has a small footprint. The way we cut the ski section and boat hull created such a great fit of the two. I couldn't have picked a better donor ski. Because the weight of my boat is heavier than the XP, I think I will be able to reach 50mph. Should be a very fun boat. I will run the stock intake grate at first just to get a baseline and see how it performs. If I see any problems or room for improvement I will definitely take a look at aftermarkets ones. The Battery I'll be using is an Optima Yellowtop. The VTS will be used, and if the wires dont reach they can easily be extended.

millhouse961- Thanks! I am very anxious to have this thing floating!

So after cutting the transom to allow the pump to sit flush with the bottom of the boat we found some wood that is starting to rot. I am hoping it's limited to an area just around where the outboard was mounted, but it may be worse. I was thinking tonight...the boats transom is relatively small. If I do decide it's necessary to remove all of the wood, would it make sense to lay up fiberglass chop mat up to about .75"...basically creating a composite transom? I think i have plenty of material to do so. Would there be any drawbacks?

Thanks!

So my brother and I had been discussing the transom issue for a couple days. We were going back and forth on whether we should replace the entire transom, patch repair it, or just hope it was just a little rotted where the outboard bolt holes were (where we would be cutting a section out for the pump nozzle to exit). What we concluded was that we would go home, cut another small section from the top corner of the transom to see how far the rot had gone.

We went home to my apartment last night (Weds) and exposed the top corner of the transom. What we found was that the original transom board was completely rotted. It also made it clear that at some point some idiot just slapped another sheet of plywood over top of that rotted board and glassed it in. We were very intimidated at this point. We saw a lot of cutting, grinding, chiseling, sanding ahead of us.

We went ahead and made a cut with the angle grinder all the way around the transom, through both layers of fiberglass that were containing the two boards.


We started prying gently all the way along the top cut that we made. Iimmediately the solid board start pulling away from the rotted board.




It took some muscle, but we grabbed the solid board and just pulled and ripped that F***er off. Came off surprising easy, but what shocked us even more was HOW ROTTED the original board was...it was flakey MUSH.


It was such a relief because with a chisel and crow bar we were able to just skim it off the outer fiberglass/gel coat skin.

This did, however, leave us with a lot of fiberglass to grind down. I didn't get a pic before we started grinding, but in these pics you can see we grinded the extruding edges of fiberglass down level to the floorboard and transom skin.






The Newer Board


The Original Board

We're getting VERY close to GLASS! Check out the inside view of the ski part in place.






Back View


So to end Wednesday Night we were extremely happy with the work that we put in on the transom, and very happy that we dug deeper on this issue that could have been easily overlooked, and come to HAUNT me later.

Iworked a boat claim last year and I inserted my finger through the transom next the the backing plate on a Merc, it was like foam, a real mess and about ready to fall off.

Originally Posted by Forkin' Crazy

Cool project.

I didn't see this mentioned, so I will. When I was building/repairing boats and doing repair on jet skis, the resin is not the same. Polyester resin will delaminate from injected molded fiberglass. We had to use SMC resin. Feel free to double check this, in fact please do. I wouldn't want you to do all that work and the pump intake delaminate from the rest of the hull!!!

Is injection molded fiberglass the same as Fiberglass Reinforced Plastic (FRP). I know the newer skis use this FRP, but I have confirmed that the early seadoo's, including the XP, used a polyster resin/fiberglass layup. This was one of the reasons I chose the XP as the donor. Please let me know if I have overlooked something though. The last thing I want is to have this section delaminate.