35 inch scratchbuild Cat from NZ :P

[crabstick]

Hey Guys

Thought I would share some of my build

its 35" LOA, 33 inches of wet surface. I have based it on a similar Cat that I built last year. long and narrow, they seem to turn and ride well, my problem with the last one was it was too light and being balsa destroyed a sponson on a fast blowover.Built from Birch Ply and spruce, sealed with Everdure, then a thin coat of epoxy over the entire inside of the hull. At the moment It has no spray rail and I may add one if it needs one.

I Have a kb45 8xl to power it and some Zippy Flightmax 2650mah 30c 4s lipos that I will run 4s2p. The esc is a Hextronic 120amp watercooled ESC, ive given it a beating and it just keeps on ticking, once that goes it will get replaced with an ETTI

I have painted the basecoat as to show up the imperfections that i am going to try and get out after initial running.








im yet to decide on a name but ive narrowed it down to

the purple people eater

Purple Haze

or "Richard"

[Simon.O.]

Nice build there Matt.
I like the no step design and keeping the spray rail off until you know that it is needed.
I hope to get doen to Wattle or Hakanoa and see this thing fly.
Do you know the weight of the bare hull ??

I vote for Purple haze.

[crabstick]

the weight of the hull bare was 1.1kilos

ive today mounted the hardware and made a carbon cooling jacket for the kb45. Thanks to Epower for the carbon!! I am just in the process of making carbon engine mount, then i will cut the stuffing slot and line everything up awaiting my coupler!

[Zero_Limits]

Your coupler... yea I should probably finish the drawing and send it off to the engineer aye

Boat looks good, your best work yet I would say. Not sure on the colour though, did you loose a bet with your mrs or something?

[lomdel]

We need pics of the hardware and install, please!! Great build. Not sure about the effect of no steps though. You should really roughen up the bottom of the sponsons to avoid it sucking to the water.

[crabstick]

Will post pics later tonight phone is flat at the moment.

Yes Bruce ... Git my coupler LOL!!!!

ah i dont think the steps will make much difference. only the last few inches of the sponsons will be in the water anyway

[crabstick]

The power sources






Sorry for the bad pic, the phone takes really bad pictures under artificial light and its dark outside

Hardware is a mix, its a speedmaster 45 sized strut. 3/16 speedmaster flex cable and stub, fullers rudder arm and rudder off custom brackets. I have another rudder should it not turn.

On the no steps thing, Im sorta just trying something different, I know water doesn't scale down like a lot of things..... food for thought, thats another thread entirely

[tylerm]

looking good dude, how was the carbon dust

[Simon.O.]

On the no steps thing, Im sorta just trying something different, (not real different ) I know water doesn't scale down like a lot of things( correct )..... food for thought, thats another thread entirely

Like this one??
http://forums.offshoreelectrics.com/...ead.php?t=6576

Matt, don't sweat the steps thing. During my research I had a lot of PM's come my way from some well experienced model boat builders and users. The steps thing is a very contentious issue. Go the way you are and see what happens. Talk to Graham Dogget if he is still around at MMPBC, he knows a bit about cats.

[Xzessperated]

If it goes as well as it looks you will be very happy Matt. You have done a nice job. I am watching with a great deal of interest.

[crabstick]

thanks Guys

Tyler - Carbon dust was ok cause i just sprayed water on it while i was cutting the carbon, no dust yo! (old trick from when I was a mechanic, used to do the same with brake dust) ended up using hacksaw, worked fine

Simon - Yeah, the last Cat had no steps either and I did very little development power and prop wise and got 53mph from it on a 8xl and 4s2p x440/3 prop.
I think steps on a larger boat might be worthwhile to reduce drag, but on a hull this size I am not sure if they are needed. Good thread you linked me too - Cheers.

Xzessperated - Thanks!! Hopefully I will get the motor mounted and the cowl made today then i just need a coupler!

[crabstick]

just tested my carbon cooling jacket. NO leaks under a lot of pressure from the electric nitro pump, ended up just pushing a carbon tube over the motor onto O rings, at first I was going to run it like that, but i discovered a leak under pressure so have siliconed it for safety, if i get a blockage etc i dont want the boat filling up with water. pics to come

[EPower]

just tested my carbon cooling jacket. NO leaks under a lot of pressure from the electric nitro pump, ended up just pushing a carbon tube over the motor onto O rings, at first I was going to run it like that, but i discovered a leak under pressure so have siliconed it for safety, if i get a blockage etc i dont want the boat filling up with water. pics to come

Looks like you been going hard m8 and managed to make that water jacket

[crabstick]

Yeah M8, Cheers again for the Carbon

Have Started on the Cowl. it pretty small, the boat looks like a 60 footer lol, I may re-do the cowl at some stage to get it more "scale" but for now it covers the KB sticking through the lid so it does its job



Inside with the motor test mounted.

[crabstick]

primed cockpit of the single seater 60 footer

http://img6.imageshack.us/my.php?image=img00310.jpg

got to sand etc but it will do to cover the motor for the first few runs.

That cockpit has to go its WAYY to small lol