Aeromarine Sprint Cat .80/.90 twin 1717's

[millzee]

After months of searching I decided the sprint cat 42 would make a good home for a couple of castle 1717's that I had spare. I wanted to get the hull from the factory with the carbon laid and the transom strengthened so I tried calling remmy every night for about 2 weeks (which for me being down here in OZ made many late nights), after a few post's on here, dasboata (thanks mate) helped me out and I had finally forked my cash over and was very excited. After waiting a while my hull arrived but there had been a mix up at the factory and I ended up with rails and no carbon, oh well, it's made the build more fun. I decided to leave the cross section and then removed the rails by cutting the along the joins and then breaking them away from the hull. After cleaning up the inside of the hull with the dremel and sand paper I was happy with my layout options.

[Jedi Master]

Will follow this build with interest......looks like it will be a proper beast!!!

[bbill1]

Watching this one myself...

[millzee]

I left the build for a while as I had also got the Mean Machine at the same time and I figured I'd rather get a little practice with a cheap cat build before I sunk my teeth into this one and I wanted to start the build with everything I need and I still need the flex shafts but I'm now sick of waiting for them so I'm into it and I've laid some heavy carbon cloth covering the inside of the hull from above the join on one side to across and above the other, as I was doing this I molded the cloth into the corners and up the transom, then I put another two layers across the transom. Then it was time for me to figure out the layout I was going to use, after a night or two reading post's on here and moving things around I decided I'd install the motor mount. I'm using a twin motor mount made by James Williams, he did a terrific job but I had to figue out how to mount it without adding any extra height as the mount is so wide that when the motors are at full tilt, the bolts at the top of the rear support touch the hatch right at the edges of the rise in the hatch. I decided to drill holes across the bottom of each side of the mount, then I cut left over 4-40 push rod into small lengths long enough to protrude out each side and ca glued them into place in every second hole to act as anchor points. I then mixed up some 30 minute epoxy with carbon fibre that was all the loose threads that I mulled up with scissors and fill the remaining holes in the bottom of the mount, put it in place and then pushed the carbon paste along the bottoms of the mount covering the rods. It's not the prettiest job I seen but I can lift the hull by the mount.

[millzee]

I then proceeded mounting the hardware, after a hours of reading I asked a few questions in this thread https://forums.offshoreelectrics.com/...ose&highlight=
and come up with the way to mount the struts. After mounting the harware I looked into my water cooling options. I have a few under hull pick ups as well as the dual pick up rudder and was thinking to run a seperate line to each motor and esc but I figure I'll just use the rudder pick ups and run one line to each esc then through the each motor and out of the hull. If I find the temps a little high, I'll always be able to add the under hull's at a later date as I'm not going to rush in painting this boat untill it's running great on the water.

[millzee]

As you could see from those pic's, another week or so past waiting for the flex's and I figured I'd mount the rudder servo and get that all fitted. I made a servo mount out of 50x50x3mm aluminium and then epoxied it in the same way I did the motor mount.

[millzee]

Since then I've now started work on the electronics, I'm using the T180's and have borrowed one of choppers mods, it make them both fit on the tunnel nicely, thanks chopper. I've added three extra caps and 8mm bullet connectors to one of the esc's and I'm using M3 dual lock velcro to hold them in place, thats some strong stuff, the only negative I can find with that stuff is getting it to unlocked. For battery holds I think I'll run with velcro in the sponsons and pool noodles on top, I was thinking at one point to make up a leaver brace/latch that could push across from the floor of the tunnel and over the batteries but I'm thinking that might be a little overkill. Now all I can do is finish off the esc's, get it all calibrated and bench tested and wait, I don't want to install the stuffing tubes until I have the flexs. Here's a few pic's of the esc and the deadlock I'm in.
P.S. Any advise on bending an s-bend stuffing tube would be appreciated!!!!!

[millzee]

this is just a few pic's for size comparison with my MM

[millzee]

My flex shafts finally arrived today so I can move forward with the build, now I'll have to figure out how to bend an s-bend stuffing tube and how to set up the strut. I'm thinking that I'll use 1/4" brass and run from the coupler, through the hull and then just into the strut enough so I can install the brass bushing. Again, any advice on this subject would be appreciated.

[Make-a-Wake]

WOW! Nice build here millzee...............those twin 1717's will get that baby movin' for sure! You addin' extra caps to the other T180 too?

I shortened my wires which is ok according to Castle................i lopped about 5 inches off...........less amp loss/heat.

[millzee]

yeah mate, I'm going to get stuck into the rest of the electronics tomorrow night, I've got caught up tonight installing a big block 1406 5700kv castle into my merv. I will add extra caps, do the wire tidying and what not, then I'll have a crack at the stuffing tubes. I'm planning on using 1/4" but do you think maybe 9/32" would be better allowing more clearance for the bends and then just reduce it at both the coupler and strut??

[Make-a-Wake]

Going back over the pics i noticed you have the motor plumbing backwards.....................if the ESC is getting cooled first and then going to the motor, the input flow line should be at the bottom of the motor and water flow output should be at the top.

[millzee]

cool, thanks for the tip, easy fix. What about the stuffing tubes??

[scoota]

Very nice build millzee !!!!

[JCAustralia]

Impressive!

Looking forward to see a vid of that beast

JC

[millzee]

Thanks guy's, offer me some advise will ya, should I run 1/4" stuffing tube or because of the extra bends (s-bend), should I run 9/32" and just reduce it at both the strut and the coupler??

[Make-a-Wake]

I wish i had an answer for ya millzee, but i honestly dont........................

[Rumdog]

Use 1/4" . I use it even with minimal bend in the tube.

[millzee]

Use 1/4" . I use it even with minimal bend in the tube.

??? this will have an s-bend, I suppose I can just bend one up and see how free the flex is.

[bbill1]

Why use an s-bend? Is there a specific reason? All inboard nitro boats I have ever seen have had a gentle bend from the motor to the strut.

[bruiser77]

Because of the way the struts are mounted in comparison to the motors. Iknow it's a little late to ask but couldn't you mount the struts closer together or will it effect your prop size? Great job on the build btw.

[millzee]

Because of the way the struts are mounted in comparison to the motors. Iknow it's a little late to ask but couldn't you mount the struts closer together or will it effect your prop size? Great job on the build btw.

thanks. Here's a thread I started whilest gathering info with some pic's of them in a line with the coupler https://forums.offshoreelectrics.com/...ose&highlight=

[Brushless55]

Nice build bro

[millzee]

thanks mate, I hope to get the stuffing tubes in and seal it all up over the next few days so I can get it wet, I'm a bit excited.

[millzee]

Ok, today it's raining out side, my wife is home and happy to run the office so it's off to the shed I go.
I now have a couple of the 240amp Aquastar speedo's to use instead of the t180's so I'll play around with the layout again and make sure my cog can adjust from 29+%.
I through it on the scales before fully loaded and it look's like fat cat is back, 8.5kg's with no lid, how's that weight??

[millzee]

It's been a great day, I managed to get plenty done but for now I'll only show a few pic's as I need sleep.

[rearwheelin]

I like it very much...... Why weren't you able to get the J bend ? Not enough hatch clearance ?....... I did a simullar build with a conquest and was barely able to scweek J bends, I also was able to do 5" motor spacing to keep prop wash off rudder...... Mainly wanted to tell you that the fella who bought the boat is 100% happy with the twin 1717, T180, 6s 4p setup and has had zero issues with 3/16" cable thrusting with the struts via octura thrust washers....just wanted to let u know mate keep the thrust at the transom so your motors don't lift your boat and add load to the cable doggy .... If you haven't seen the twin conquest get at me and I will link you up ! Enjoy

[rearwheelin]

Ran like a champ first go out..... I keep in contact with the owner and he says he can do 60mph full speed turns on 6s.... First run , you may have seen this.... http://m.youtube.com/watch?v=9BGu9LH-rOM

Oh and the wieght is without batts? My conquest quad drive with 6s 4p 20000mah was 22lbs and plained up good....

[millzee]

I did see that one, good job, thanks for the tips. I'm going to do the stuffing tubes this afternoon, then I can focus on the hatch seal, electronics and then I should be able to pull the pin, excuse the pun. I was a tad concerned with the 180's in a hull that size so the 240a aquastars will give me a little more piece of mind.

[Rumdog]

Great job! The Aquastars will be great. They won't even break a sweat with that setup. I may have missed it, but are you starting with C/R x447's? Do you have any props yet to try out on her?

I'll be converting my gasser Sprintcat this summer with a single drine and 5692 Leo.
You're gonna love the sprintcat!