Motor for a 12"-14" Cat (single)

[BakedMopar]

IMO the 380 cans are too heavy (especialy the L versions which are 58mm long) and eat too much amps. While I can only speak for a 17.5" hydro thats my take. A buddy runs a couple of Minicat stuff with 20mm motors and they are fast and have decent run time. He gets around 4-5 minutes wide open in his hydro with a 2200 pack. I get 1-2 minutes out of a 2200 pack with a Feigao 8l.

If you really want a 380 size (28mm) go with a short can 45mm and under. With a 380 you can spin a bigger prop. But you need higher amp escs.

[Simon.O.]

I have done a bit more thinking on this one and have come up with an interesting idea.
My ~34"cat has about 1600W of calculated power and run well.
My ~25" cat ( now dead) had about 1000W of calculated power and was very fast.
I see a pattern here
About 70% hull size reduction runs on about 70% of the power, so far so good.

One new hull i plan on build will be 18"(wet) 20"loa and most of my reading points to about 750W power setups. This is where the light bulb came on.

The smallest cat on the paper at the moment will have aboat 13"wet and 14"+ loa. This should then get by with about 250W of power.

I did a few paper cutouts and have shown my "formula" to be based on plan view sizes. Given that my cats are close to the same design and proportional build construction I now see this as a power to size ratio.

Now all I need to do is suit up about 250W of power to feed to a 27mm Graupner prop.
I plan to use the Graupner 2318 series M4 threaded props until I find the right size and then if needed go to a metal one.

Possible power combo#1
20x40mm (130L) 4850kv Inrunner max load 25A?? (185W) Add more for short sprints with cooling !!
40A esc
1600 30-40C (48-64A) 2S1P pack

Possible power combo#2
24x35mm (370s) 4400kv Inrunner Max load 26A (192W)
Same pack, and esc.

Last resort is to go with a 380S.

I am leaning toward the smaller motors as that seems to be a fairly successful size to transplant into the Pro-Boat Mini-C and I have seen a few clips of them going nuts on small setups.
This is deffo a fun boat, not a saw or racer.

I am enjoying the research and thought that all of this takes.