Custom/Hybrid Complete build. Custom flat water carver ski.

[Yami-Rider]

I see. Will be interesting to hear how it handles. What is the length and width?

What total oz layup are planning to shoot for on the bottom deck? Looks like your using plain weave E glass.

 

[Bulletbro]

Width is same as a SJ - 680mm
Length is 2360mm - SJ is 2240mm so it’s 120mm longer than a SJ.

The base has 4 layers of 300gsm plain weave + With all joins having 3 layers of 200gsm as tape.
1 final layer of bi-axial 200gsm over the base.

When I build the bulkhead through middle and the mount for the pole support bracket I was planning to reinforce these parts internally, possibly vacuum bag the internal floor over the reinforcing.
I’ve got a roll of 300gsm chopped strand matting.

What would you recommend?

I could probably source some pre-preg cloth if that’s better, I’ve never used that.

It’s all in epoxy

 

[Big Kahuna]

Width is same as a SJ - 680mm
Length is 2360mm - SJ is 2240mm so it’s 120mm longer than a SJ.

The base has 4 layers of 300gsm plain weave + With all joins having 3 layers of 200gsm as tape.
1 final layer of bi-axial 200gsm over the base.

When I build the bulkhead through middle and the mount for the pole support bracket I was planning to reinforce these parts internally, possibly vacuum bag the internal floor over the reinforcing.
I’ve got a roll of 300gsm chopped strand matting.

What would you recommend?

I could probably source some pre-preg cloth if that’s better, I’ve never used that.

It’s all in epoxy

For high speed carving you need built in strakes. This looks a lot like the bottom of the original waverunners. They were fun hulls for sliding. Turning? Not so much.

Sent from my SM-T700 using Tapatalk

 

[hink320]

Width is same as a SJ - 680mm
Length is 2360mm - SJ is 2240mm so it’s 120mm longer than a SJ.

The base has 4 layers of 300gsm plain weave + With all joins having 3 layers of 200gsm as tape.
1 final layer of bi-axial 200gsm over the base.

When I build the bulkhead through middle and the mount for the pole support bracket I was planning to reinforce these parts internally, possibly vacuum bag the internal floor over the reinforcing.
I’ve got a roll of 300gsm chopped strand matting.

What would you recommend?

I could probably source some pre-preg cloth if that’s better, I’ve never used that.

It’s all in epoxy

You can't use CSM with epoxy resin, epoxy doesn't break down the binder in the CSM, you can only use it with polyester resin, so I'd stay away from the CSM.

I was thinking the same thing as @Big Kahuna. It looks like a fun sliding ski, not so much a carving or turning ski. Check out the pics of the bottom of the Pro Force hull (there's a build thread somewhere on here.) It's a long hull like yours, it's built for carving and turning but it has some crazy strakes on it.

 

[Yami-Rider]

300gsm = 8.85oz 200gsm = 5.90oz .

Had to look it up, only use oz in the US.
That is some pretty light material. A harness weave s-2 glass would be alot stronger, I like 8 harness, they make 4,6,8. I personally like working with 475-675 gsm for easy layup.

I would shoot for atleast 1800gsm+ on the bottom. No one has built a ski like a boat in recent times, so not totally sure on layup. Full fiberglass a/m hulls use a final layup ranging from 3400-6800gsm threw out the hull.


Don't use chopped, it's weak, heavy and epoxy doesnt break down the binding glue, like hink said.

You would want to wet lay vac bag, if you did any of that, it is the cheapest type to get into. Infusion and pre-preg is faster, but you need a gaint oven for pre-preg and infusion cost alot more to get setup.

 

[Bulletbro]

300gsm = 8.85oz 200gsm = 5.90oz .

Had to look it up, only use oz in the US.
That is some pretty light material. A harness weave s-2 glass would be alot stronger, I like 8 harness, they make 4,6,8. I personally like working with 475-675 gsm for easy layup.

I would shoot for atleast 1800gsm+ on the bottom. No one has built a ski like a boat in recent times, so not totally sure on layup. Full fiberglass a/m hulls use a final layup ranging from 3400-6800gsm threw out the hull.


Don't use chopped, it's weak, heavy and epoxy doesnt break down the binding glue, like hink said.

You would want to wet lay vac bag, if you did any of that, it is the cheapest type to get into. Infusion and pre-preg is faster, but you need a gaint oven for pre-preg and infusion cost alot more to get setup.

I have miss quoted the Matt I used for the initial shape, it’s 600gsm
See this pic, was quite a heavy thickness.


Anyone want a 10m roll of 500gsm chopped strand matting..

Thanks for the helpful input everyone, awesome

 

[Bulletbro]

For high speed carving you need built in strakes. This looks a lot like the bottom of the original waverunners. They were fun hulls for sliding. Turning? Not so much.

Sent from my SM-T700 using Tapatalk

Yep, the bottom is pretty well flat like the slippery old waverunners, but I’m focusing on the chines , hoping that being able to tip this and bank it into a turn will push that outside chine (edge/corner) deep and the reverse chine will hold on.
That hull edge is opposite a normal jet ski hull that has a radius on it.

The waverunner was also much wider (from memory I chopped about 180mm from each side) so tipping it sure wasn’t easy and skipped like a river stone if turned hard.

Reverse chine.


I may be overestimating the ability of this chine to hold but my body weight will also be right on top of it.

I’ll check out the pro force hull and strakes, might need to add them.
Thanks for the helpful comments.

My jet ski mates that come around to the workshop and look at this hull in the flesh think it’s going to grab too hard and high side me!!
They want tickets to watch ..

 

[Bulletbro]

This is the pro force hull, couldn’t find a better pic from the stern. Have increased height and shape of strakes. Still on the same hull line as SJ . Can’t find a pic of the chine , appears to have the outside edge turn down.



I’ve sketched the changes I’ve made to a SJ on the left hand side of this pic.



Plus some other changes of engine forward, longer overall, wider tray, longer tray.

I’m also aiming to lower the overall height in an attempt to lower the centre of gravity, may not make a big difference as the engine height/pump to waterline isn’t changing.

 

[hink320]

This is the pic I was talking about:

 

[Bulletbro]

This is the pic I was talking about:

Thanks, extra strakes closer to midline. Square chine... interesting.

 

[Bulletbro]

Bored waiting for parts to arrive so I can continue...

Rigged up a twin carb fuel primer splitter.
Using the carb manifold for a ...er... manifold.

Probably been done a million times in other ways but anyway..

 

[Just4Fun]

Bored waiting for parts to arrive so I can continue...

Rigged up a twin carb fuel primer splitter.
Using the carb manifold for a ...er... manifold.

Probably been done a million times in other ways but anyway..

View attachment 348357

Wow never saw that before but you only need on carb primered...

 

[Bulletbro]

Wow never saw that before but you only need on carb primered...

Yeah, Just thought it’d be better to wet both cylinders out with fuel/oil rather than one and let the other run dry till fuel comes through.

Not really solving any problems , just bored.

 

[Nate007]

Nice build, can’t wait to see the finished product

 

[James Findling]

Wow never saw that before but you only need on carb primered...

I prime both, just using a T-fitting, not through the manifold. Definitely better than dry starts on a cylinder IMO.

 

[Storbeck]

Beautiful craftsmanship!

 

[Storbeck]

Any more progress on this thing? I really wanted to see and hear how it turned out.

 

[Mdavies_02]

x2. Just read through it for the first time. Excited to see how it goes
2

 

[Storbeck]

 

[JKMike]

Sweet build!