Thread:

Addictor 333 Mini OB boat to 110hp Jet Boat Conversion

I made a post back in Sept 2011 showing my Addictor 333. It's a 12' mini outboard boat that came from the factory with a 40hp outboard. When I bought this boat last year it ran about 27mph on GPS, and took forever to get there. Even though it's a shorter boat, the fiberglass/wood hull make it much heavier than your typical aluminum fishing boat. I decided the outboard wasn't cutting it.

This is what the boat looked like in March.




I've been considering a big overhaul to my Addictor 333 10ft boat for some time now. I really want to create something different/unique. My concept is to convert this mini outboard boat into a jetboat using the engine and pump from a 1996 Seadoo XP (787cc 110HP 2-cyl). There is obviously a wealth of knowledge here which is why I am excited to share my concept and my progress throughout this build.

The original Concept.


The revised Concept (including new interior design, paint, and exterior graphics




I have been making progress the last couple of weeks and have been posting that progress on another forum. Since I wasn't posting here, and I know there were several that were interested in watching my progress I will catch you all up quick, and then make updates as I go.

3/15/2012
A couple of weeks ago I sold the outboard Nissan motor to a guy in Maine, and stripped down the entire boat to get it ready for the conversion.

STAGE 1: Weight Reduction

Motor Off and Radio Out


Controls and Wire Harness Out


Tilt&Trim Off and Fuel Tanks Removed


Interior Removed


Grungy Old Carpet Removed


Bare A$$






Now I have to do some Scrubbing!


a week ago I put money the money down to have a 1997 Seadoo SPX completely rebuilt by a local race shop. He said it would be two weeks until I get the ski which means it should be well on it's way and I should receive it on March 22nd (a day after my Bday)

I also just ordered 15 sq. yards of 1.5oz chopped mat, and 2 gallons of polyester resin online from US Composites.

3/23/2012
Small update. Got this in the mail on Wednesday. Another gallon should have been dropped off the same day. I think the ups guy didn't notice box #2. He came back yesterday though and dropped it off.



I gave Rob at RSI a call yesterday for an update on the SPX he is building me. It was supposed to be finished yesterday. I didn't get a call back so let's hope I hear today!

Lastly, I just purchased a new vehicle. previously I towed my boat with my 2004 Black Toyota Solara Sport. You can see how it looked before in this pic.



Well I was in an accident a few weeks ago that totaled it. So it gave me a chance to upgrade it. Since I loved the car and already have wheels, a hitch, and other aftermarket stuff for it I decided to get a similar car but newer with more bells and whistles.

here is the replacement. It is a 2007 Blizzard Pearl Toyota Solara Sport. I chose the color because I will be painting the top half of my boat the same Toyota Blizzard Pearl white.







The car and boat will be a pretty nice pair after I am finished with them both.

4/5/2012
The beginning stages of the conversion should begin this weekend!

4/15/2012
I thought I'd be cutting by this weekend but I didn't get the tools needed from my buddy and was also busy getting other spring things done. I did take all measurements needed to place the motor, and planned the cut lines. After taking a good look at where the cut lines will be and how things will align, I determined I could not have picked a better ski. The footprint of the bottom of both boat and ski will make this a seamless swap. All of the lines match nearly perfectly and boat flattens out near the front into a flat 5.5" strip all the way to the back of the boat at which boat the flat parts widens more. The width of the 5.5" strip matches perfectly to the channel that leads to the pump intake on the ski, and the wider flat part near the back of the boat will make a perfect surface to glass the pump intake in. I'll explain more when I start cutting so I have better pics for reference.

This pic shows the bottom of the ski nicely and you can see the 5.5" flat strip that leads to the pump intake. The boat has nearly the exact same design which will provide a smooth water flow/channel to the pump.







These 2 pics show the rough placement of the motor. I left about 1.5" clearance to the back of the seat. Also the motor will drop about 1.5" once we notch the subfloor between the two stringers. We will be moving the cross support between the stringers to right under the seat back. We will then put another cross support between the stringers right behind the motor and notch it for the Impeller drive shaft.



I'm thinking this type of placement for the waterbox, and run a splitter hose off the exhaust outlet into two exhaust tips



Here you can see there is nearly 17" of room behind the motor for the pump to fit. That is exactly what the pump needs, so the pump shoe (where the pump nozzle mounts) should be nearly flush with the boats transom.

4/19/2012
Started by separating the top of the boat from the bottom with a reciprocating saw (AKA Sawzall).


Exposing the inner structure. to determine cut lines.




Where I am cutting in these next photos is recessed channel where the motor will be mounted. We had to lengthen this recessed area so the motor will sit level with the boats bottom and in turn let the pump sit flush with the bottom of the transom.






Above, you can see I cut a little peep hole to see what else I was getting into. Good thing because this is when I found out about the LARGE center stringer.

I didn't get a pic of the section removed, but you can see the area in these pics showing how the motor now sits flush with the bottom of the boat. The recessed channel now runs the entire length of the rear hatch area.








There was a lot of sweat, dust, and itchiness. I can't wait for a couple more weeks of this!

PS: I am relatively new to boats so please help me with boat terms along the way if you can. If I refer to something incorrectly it would help me to know the correct term. Don't be afraid to chime in.

4/21/2012 (post 1)
So we started Friday night by hanging some plastic to section off our workspace in my apartments underground parking. Who said you need a shop? haha.




Next we masked off the XP where we wanted the cuts.


This morning (Saturday) we started by removing the speed sensor hardware from the ride plate. Then used a small jack to pry the ride plate from the XP hull.






Drilled through the corners to locate the cut lines on the inside of the ski hull. This XP is multiple layers thick in some areas so the angle grinder would not cut through both sides at once.


Then it was all cutting from there.


Next we cut the lines anywhere it didn't go through both layers of the hull. (No pics of cutting the inside)

The hull hole


The section that will be glassed into the boat. It needs to be refined first. More pics of that to come...hopefully tonight.

Very cool project. I think there is 1 or 2 other people doing similar projects also. These were being discussed in the jet boat section a few weeks ago. You have my interest in how this turns out. Keep up the info and pics.

4/21/2012 (post 2)

Here are the photos showing how we refined the shape of the ski section that will be grafted into the boat. What we did was just remove any fiberglass that stuck up (the inner layer of the hull) from the bottom layer of the ski's hull. The exception was the motor mounts. We left those and will then reinforce them by glassing from the top of the mounts outward, towards the boat, once that section is grafted into the Addictor.

Here you can see we removed some fiberglass near the top left and bottom left corner of this photo. We hadn't cut one of the rear raised sections out yet.




Now you can see that we cut the rear raised sections out, removed the foam that was in between, and then grinded it smooth with the lower fiberglass layer.


And in these two you can see how all raised sections, except the motor mounts, were cut off and grinded smooth, with all the foam removed.




And that section of the ski placed in the boat, with the engine sitting on the mounts. The ski section is set inside the boat in this pic, and won't sit flush in the recessed area until I cut the hole in the bottom of the boat, and also out the back where the pump shoe will exit.










I should have more work done tomorrow. Hopefully the boat will be completely cut and ready to glass!!

4/22/2012 (post 1)
Sundays progress was held up by an unforeseen problem. How to get the boat bottom flipped over. My brother, Nate, and I can barely lift it, let alone flip it while holding it up. So we thought of every way possible to flip this beast of a hull. It probably weight 400 lbs. So since we don't have a hull rotisserie we had to improvise. We built an inner structure to support the sides of the hull and distribute the pressure from the weight of the boat. Then we tilted it up onto one of the sides and then went to the other side to lower it back down. The skeleton we built definitely help and there was no bowing/stress cracks/etc at all. We also put old couch cushions down on the concrete to distribute the pressure that would have otherwise been directly on the lip of the hull where the top and bottom of the boat meet.

Here is that wood structure we built.


Then we measured the length of the section of the ski and determined we wanted it to sit back 3" from the back of the boat. So we took that length measurement, subtracted 3" and marked a line on the boat that was that same distance from the back of the boat. At that line we measured how wide the flat part in the middle was, and we made the ski section angled so it would be a nice gradual blend from the flat part of the boat to the flat channel in the ski's hull that eventually flows into the intake grate. Any abruption in that surface would decrease water flow to the intake.

Here you can see the angled lines marked on the ski that angled inward towards the front to create and nice gradual/dynamic blend.


We eventually cut the ski section along the lines in the previous photo, and then transferred the shape of the ski section to the bottom of the boat.


From the outline on the boat we measured inward .5" from all sides and cut that shape out. That left a .5" trim where the ski section and the boat overlap. We then feathered the edges of both the hole in the boat and the ski section so they mated nicely. We still have some refining to do so they sit perfectly flush.

This is where we got to tonight.

4/22/2012 (post 2)

With Rideplate set on
















^^This was a GREAT feeling seeing how well they mated, after all the work we put into creating these shapes.

All in all tonight went very well. It was a LOT of measuring. We probably spent 3-4 hours just measuring and drawing lines, transferring the shape of the ski onto the boat. It was very difficult because of how lines get skewed over curved/angled/odd shaped surfaces. We triple measured everything and it payed off. A lot of fitting, grinding, fitting, grinding...until everything sat flush.

I owe my brother Nate greatly. He has been plugging away at this with me every time I have worked on this project so far. And this is hours and hours of being covered in fiberglass dust and being bundled up in particulate suites, respirators, protective glasses, gloves....sweating, itching, bleeding a little here and there. So big THANKS to you Nate! The labor intensive part is nearly done though...thank god!

My favorite toy is my 1996 XP RAVE engine, it hauls butt and is nimble. I would suggest adding a lowered intake grate they are aftermarket and run about $90. It elimiated cavatation and really sucks up the water. Keep us in the loop, this is a nice project. My Xp runs about 55 MPH. Never had an issue with the engine since new. I would also use a larger battery than a ski battery, perhaps the original tray uses a small marine battery??

I would think the electric trim control line should reach??

Awesome Project,Love it.