Flatbottom ski boat convert to electric help

[GoFastNow]

I have this flatbottom ski boat from the 70s. It was originally a give away when you bought the real boat. I want to make it electric now. Its 35" long, and the bare hull weight is a little over 4 lbs. Plenty of room for batteries. I have no idea of a speed goal since its a flattie, maybee 50 mph?. Any sugestions on motor, batteries, and prop would be great. I think it will need a sub-surface prop?scotts flatie.jpg

[bogieboy]

being a flat bottom i would set it up like a crackerbox, but i have no ideas on what to recommend for power... probably somewhere in the 3670 to 4090 ish range, probably 1500kv on 6s with around a 45mm 1.4 prop?? the OSE speed calc says that combo should do around 47mph factoring 25% prop slip... im still new to the rc boating world though, so dont take my opinion as fact...LOL i am more in tune with the gas side of things than the electrics...

[Fluid]

Back when these nitro models were new, their speeds were generally under 40 mph. Hull and drive design do limit the practical speed, and some hopping is to be expected.

Models this size usually run on 6S power, although 4S is possible if high speed isn?t a goal. The minimal amount of work would be to use the existing drive connected to a 40x82mm motor with a KV around 1200. Not many FE boats are built with submerged drives, so the prop choice will need some experimentation. An x448 might be a good place to start With potential speeds in the low 40s. Get more feedback before you start buying parts.

Here are some threads covering electric conversions to give you an idea what you?ll be in for.

https://forums.offshoreelectrics.com...ght=Conversion

https://forums.offshoreelectrics.com...ght=Conversion

[GoFastNow]

All suggestions appreciated. Do I need to go with lower KV because of overall weight of the boat? Will I need to go to 8s in order to get the RPM up to 25,000 - 30,000? What KV for possible 50 mph setup? Thanks
Again

[Screamin Creedmoor]

I had a similar set up flattie 33" customer built...here was my set up:

VXP Racing 220amp ESC (6s-12s), SSS 4082/2000KV brushless motor on good quailty 6S graphene battery slinging a Octura X445 (balanced/sharpened) ...58 mph on glass pond...and could probably get a tad bit more out of it.

Good luck!

[GoFastNow]

Nice, thank you very much for the input. That set up makes sense to me, and the speed should be plenty. Were you running the prop out back, or was it under the boat? and rudder inline, or offset?

[Screamin Creedmoor]

Nice, thank you very much for the input. That set up makes sense to me, and the speed should be plenty. Were you running the prop out back, or was it under the boat? and rudder inline, or offset?

Inline Rudder and prop was a under boat on a flex shaft. Shot a rooster tail about 5 foot in the air and 6 foot back! Was a screamer!

[GoFastNow]

Awesome, once again, thanks so much for the help.

[IGGY_357]

https://www.facebook.com/1815007984/...055249?sfns=mo

As a thought, we run 4074 1800kv with an Octura M445, OSE Raider150, on 4s

[ranger18]

All suggestions appreciated. Do I need to go with lower KV because of overall weight of the boat? Will I need to go to 8s in order to get the RPM up to 25,000 - 30,000? What KV for possible 50 mph setup? Thanks
Again

I have a 36 inch Dumas ( true flatbottom) with a leopard 4082, 1600 kv, Seaking 180, on 6s. the bare hull is 7 lbs, it went 64 last weekend with a ABC 1817-17-45-2, A little sketchy, the boat was a lot more controllable with a 642 prop I am building a 36 inch capsuled runner bottom which is what your hull is (runner bottom) that the bare hull will be about 2 lbs 9 ounces in paint and I will have a Leopard 4082 1800kv on 6s. with a stinger drive, https://forums.offshoreelectrics.com...my-first-Build