Scratch built 21ft Ski Race Prototype

[Primal 98]

G'day all, I thought I might share a few pictures of a project I have undertaken over the last 5 years or so. It has been a project that has been on my bucket list for decades.
The concept was to build a prototype waterski race boat that could serve as a test platform and perhaps a plug to create a production mould, if testing proved performance was of an acceptable level.
The design was based around the international formula 2 category with 21ft deep V designs with internal ballast systems been the standard.
Whilst far from a production standard, the hull is now to a state of completion where it can be rigged and tested, however due to a recent relocation, the testing and fine tuning phase will progress at a far slower rate than previously planned.
Enjoy.
Phase 1 building a mould:

[Primal 98]

The mould was built on a framing timber strong back with 1/2" ply bulkheads spaced at 500mm centres (apologies for the mixing of metric and imperial). The bulkheads were joined together with framing timber and then dressed in 12mm meranti timber stips. I found these to be highly flexible and easy to work with. All meranti was clamped and glued into position with construction glue. Once I was happy with the final shape I cut cardboard templates of each section (you can see one for the plank area in one of the pictures) and transferred these to 3mm ply. The 3mm ply was easily cut with a stanly knife and finally was clamped and glued into place with construction glue.

[Euroski]

Cool, is that in what was your living room(LOL)?

[Primal 98]

Yeah, it was in the living room of an old fishing shack down the back of my property. It was earmarked for demolition and I thought to myself that I would never get a better opportunity to build a boat than to do it in there prior to the knock down!
Keep an eye out for the condition deteriorating thoughout each process of the build!

[Primal 98]

Once the mould was trued up it was painted in resin and covered in a slurry wax. I then pinned, wired and or clamped 12mm h80 divinycell to the mould, edge glueing each sheet the the others. In the transom I laid up 1" of marine ply (2x 1/2") across the full width and another 1" (2x 1/2") across the centre section. Also timber was added where the bung would screw through.
This again was faired where needed with a Q cell and milled fibre mix and finally painted in vinyl ester resin.

[XstreamVking]

That's a lot of work. But well worth it! Glad to see you are living out your dream. Not many things more satisfying than building some thing from just your thoughts and making it become a reality. Your face is gonna hurt from smiling for days when you finally rig and run it for the first time.

[jpf091959]

Neat to see, it brings back memories. In the early 80's did something similar. I liked that boat, we used it for skiing. It ran 70-75 with a Olds 455 on Nitious, and a Marine Power Model 105 racing outdrive.

[Primal 98]

Thanks for you comments guys, very much appreciated. jpf091959 your boat looks sick! I hope we have similar enjoyment of our boat.
Next up I layered up 4 layers of 450gr Biaxial with vinyl ester resin on the bottom and 3 on the sides (special thanks to a local pro who provided sound advice to my barrage of newbie questions- I think I owe you first ski!).
This boat was never going to be a lightweight, and my overlaps resulted in 8 layers on the running plank.
Due to my inexperience I layed these 1 sheet at a time, grinding the overlap areas and reactivating with acetone between sheets.
By this stage, any thoughts of salvaging the floorboards had gone out the window!

[OFFSHORE GINGER]

From the looks of things you are running a Stern Power IO correct .........................

[OFFSHORE GINGER]

I hope you do not mind that i re-worked these two pics for all to view .

[OFFSHORE GINGER]

Once again i hope you do not mind that i made it easier on the eyes to view . Looking good.................................

[OFFSHORE GINGER]

Just curious .....................is this boat design a Glen-L design ..........modifiied ?

[jpf091959]

Just curious .....................is this boat design a Glen-L design ..........modifiied ?

Thanks for editing.
You called it, Glen-L Renegade design. I bought a set of plans and enrolled in the local community college wood working class. I was able to use all their planers and Jointer's and get some good tips from the instructor.

My wife and I moved halfway through the build and our next house had to have a garage big enough to handle the 20'10" hull and flip it over.

The boat Primal is building will be able to take anything he can throw at it. That is a lot of glass.

[rgsauger]

Primal, your glass work looks great! Congrats on a job so far, very well done! You should be very proud of yourself.

Kudos to Offshore Ginger for all your advice on my resto. Still loving it and had her out last weekend! )

[Primal 98]

Unfortunately at this point in the build I dropped my phone in the lake and lost a whole bunch of photos that I should have uploaded to my computer. Unfortunately this means I have no pictures of the cradle I built on the hull whilst it was upside down. It was very rigid and supported all of the underside of the boat and also extended up the sides to ensure the boat was held square. The way I designed it was that the side supports could be removed once the inside glassing was complete. It also had castering wheels so I could move the hull around ( in the little space that I had) to allow easier access. I also lost all of the pics showing the lifting of the hull off the mould and the initial rotating to an upright position. Finally I lost all pics showing the glassing of the inside of the hull and the installation of the sub floor structure. I have pics prior to installing the floor which I will upload tomorrow however for tonight I will add a few more pictures of the mould.