Scott's Dark Horse Pickle

[Scott T]

I got this hull off Brian Buass over 12 months ago and never got around to starting it. I think it's a great looking boat and should go very well with a P-Spec system in it (or our local equivalent).

I started work on it a couple of months back, and have been ready to prime for quite some time. But we've had lots of rain and haven't been able to paint. The weather's better, and now I've organised my pictures.

[Scott T]

To stiffen up the floor, I used carbon mat and very light fibreglass. I find the fibreglass holds the stiff edges of the carbon down nicely. Wooden or carbon rails would have also worked, but the mat gives more space in the hull. My laying up skills are nowhere near as good as the rest of the hull, but it will do the job.

[Scott T]

Next were the doublers for the turn fin mount and transom. Just some simple pieces of ply epoxied into place. Not easy to get into the sponson, but got there in the end. Because the hull is see through, it makes it easier to see when parts aren't sitting flat as they should.

This is all the gear for the boat. SV27R motor and ESC, Zippkits rudder, CMDi strut (very nice) and Etti motor mount. I have changed my mind and won't be using the thrust bearing or servo mount.

[Scott T]

I'm going to be using a 7/32" stuffing tube, so I had to shim the strut with some 1/4" brass tube. It does not go all the way though, so the larger diameter part of the Speedmaster bush goes into the back of the strut. The bush had the be cut down the suit the CMDi strut.

Mounting the hardware was straightforward, and is a nice fit for the hull. The strut is offset to the right about 1/4" to help counteract propwalk.

[Scott T]

For those interested, the hull measures 25" x 14". Transom is 7.75" wide, sponsons are 6.5" apart and ride pads are 9" apart. So not as big as the other hulls running in P-Spec these days, but would be a rocket in N2.

Our rules restrict us to 45A Proboat or Aquacraft speed controls (rules were written before the UL1 came out), so the smaller size won't be a problem here.

Or you could stuff 8S in it and set some records like Brian did! :w00t:

[raptor347]

Scott,
With the ESC limit you guys have, the smaller N2 sized boats will be perfect.

ABC 1714 or 1716 will be good starting points. That hull loves the ABC cleavers.

It's got the NAMBA N2, Q and S sport 2-lap records (just missing the P record), as well as the N2 sport SAW record. It's a pretty good N2 heat race boat as well.

That SV27R motor is strong, I've run it in my rigger pulling a full bladed 1650 with ~5.5" of cup.

It'sa bit small for spec sport hydro the way it's run here, I'd rather run a light (and lightly modded) 20 Whiplash.

[Scott T]

Hi Brian,

Thanks for the prop pointers. Are those 3 bladers? I have a Grimracer L40x57, which I think is a copy of an ABC 1614/3 cleaver. Would like to give it a try.

Glad to have some feedback on the motor. I wanted to try something a bit different, and the kV seems pretty good. I thought a UL1 motor might be a bit hard on the ESC.

Any suggestions for a turn fin? I'm unsure which shape might work well.

[Scott T]

To mark the stuffing tube exit hole, the tube was inserted into the strut before being bent or cut. I used a set square to make a few marks on masking tape where the stuffing tube ran (I made sure it was straight and perpendicular to the transom). Two lines were drawn to show the tube on the hull bottom.

The motor and cells were dummy mounted in the hull to sort out placement. This allowed me to estimate where the stuffing tube would exit the hull. The o-ring on the motor is to ensure clearance for the cooler, which wasn't mounted yet. The exit slot was marked on the bottom and pilot holes drilled.

[Scott T]

I wanted to keep the motor low, so wanted a slim cooler. One of Andrew's Kuhlers worked very nicely. It was a little difficult to fit as it's not meant for this particular motor, but some work on the o-rings had it mounted nice and snug. I use silicone to finish off the ends. This has worked great on my other Kuhlers.

The motor and mount were epoxied into the hull using an epoxy/chopped FG mix. The chopped FG mix thickens up the epoxy a bit and gives a nice fillet. I'v done this a few times now and the mounts have stayed strong and rigid. The drill bit in the coupler helped to align the motor with the stuffing tube pilot holes. The alignment was also checked using a square off the transom.

The stuffing tube exit hole was made by drilling a hole at each end and joining them using a Dremel. Final fitting was done with a few files. The strut was set at my best guess - typically level with the sponsons and very slightly angled down. The stuffing tube was cut and bent to get a smooth curve between the motor and strut.

With the stuffing tube, teflon liner and flex shaft installed, I applied some masking tape around the tube exit under the hull. This prevents any epoxy running out trough any gaps (I never get the hole perfect!). The tube was then epoxied in, and a small piece of medium fibreglass mat added the strengthen the joint.

[Scott T]

Servo mount was next. Rather than use the alloy one I had, I thought I'd make my own out of timber and carbon plate. It's simply a plywood plate, with two pine blocks cut and glued to suit the servo (HS225MG). The blocks are just shorter than the servo height. A carbon strap screws to the two blocks and holds the servo in place.

I dummy connected the servo to the rudder and glued the mount in place. I also located the ESC and RX, and added doubler plates to the hull where I want the aerial tube, safety loop and watercooling outlet. These plates and the servo mount were then given a coat of slow set epoxy. I also added a carbon brace for the stuffing tube. I'll have to add a vertical brace to the safety loop area, as the deck is thin and it will be difficult to pull the plugs apart wihtout flexing the deck excessively.

[Scott T]

Boat is now primed. Hopefully we'll have some good weather this weekend so I can paint it (and my SD29). I love the lines of this boat!

[785boats]

Looking good Scott.
Will we see some test runs at Boondall?
I've got a couple of ABC cleavers you can try if you want. The H1714/3 that Raptor347 suggested and an H1616/3 if you think it's worth a try.
All the best.
Paul.

[Scott T]

Hey Paul!

Yes, this one will definitely get some testing miles at Boondall. Thanks for the prop offer, I'll take you up on that once I see how my Grimracer prop goes. Should be quick around the Boondall Bullring!

[Team FFRB]

Looking good so far Scott.

Keep up the good work.:thumbup1:

[Scott T]

Some decent weather on the weekend, so I got stuck into some painting. I've had a set of Proboat Miss Llumar decals lying around for ages, waiting for the right boat. This is it!

Colours are simply acrylic car touch up spray cans. Inexpensive, and work well with two pack clear. The paint scheme is loosely based off one of the earlier Llumar hydros with white at the back. I just did thin stripes for the red and black, and adapted the scheme as best I could for this hull.

I painted my SD29 mono at the same time.

[Scott T]

I let the colours dry overnight and rubbed the hull back with 800 wet&dry in the morning. This helps the clear adhere, and knocks the edges between colours down a little. The decals fit pretty well, and the striping was surprisingly easy to apply. The driver head is from HOTR. Comes with arms, but just the head works well for this boat.

Once I was happy with it all I fired up the air compressor and hit it with two coats of 2-pack Protec clear. Initial reults weren't great, but as the paint hardened it seemed to flow and make for quite a smooth, shiny surface. The first photo is before the clear was applied.

I'll let the boat sit until the weekend, then I'll start fitting the components ready for running the following weekend :beerchug:

[Scott T]

She's finally finished! Unfortunately it poured rain all day today, so I won't get to the lake for a couple of weeks.

The turn fin is a chopped down Whiplash fin a friend of mine made. The mount is nice and solid, and I'll polish it up one day. The bends are aligned with the floor of the boat, the top of the fin needs to be cut square (that's why it looks out of alignment). For now I have scribed a line so I can keep track of adjustments.

Will start with a detongued X642 until I get some ABC props sharpened. Can't wait!

[Scott T]

Final shots for now. Next photos will be action shots!

[Scott T]

I've had a few test sessions with this boat now, and the results were promising. With a detongued X642 the boat runs great and the steering is amazing! I tried a Grimracer L40x57/3 prop, but the boat got bumped in the car on the way to the lake, and the strut setting was wrong and the rudder shear pin broke, so I couldn't see how it went.

While fixing the rudder, I shortened it almost to the water cooling slot, and cut another 1/4" off the turn fin.

It's first race meeting was yesterday and had 3 wins from 3 races! Very happy. It's quite touchy on the steering, but also very controllable. Speed was up there with the others, and all electronics were stone cold after each race. Might need to try that Grimracer prop again soon.....

[Shooter]

Great boat build!!! Nice job. That 642 prop seems big.....but if it works, it works! :biggrin: Can't argue with success. I run the 40x57/3 in the vacupickle. Cavitates a bit on take-off, but it's a rocket once it hooks.

[Scott T]

Thanks Shooter! The 642 is pretty safe, everything comes in cool and doesn't seem to load the motor excessively. The 40x57/3 might load it a bit more. I might try a detongued 645 I also have here.

[scoota]

Nice build Scott !!! :thumbup:

[785boats]

Good one Scott.
Gongrats on the three wins.
It's a shame I had to go down to Tassie & miss the racing on Sunday.
I did get a racing fix though as the Tasmanian Powerboat Club were having a meet on the Derwent River. The full size boats. The V8 Thunderboats were brilliant.
Cheers.
Paul.

[Scott T]

Video!

http://www.youtube.com/watch?v=_t_c-ukhoIk

[JPriami]

Very nicely done.

[raptor347]

Scott,
You've got it running well. They're pretty solid when you get them dialed in.