Model Boat Mayhem - Forum

Dry Dock / Shipyard: Builds & Questions => Sports Boats R&D: => Topic started by: 3838Derrick on June 01, 2019, 05:55:51 PM

Title: genesis cat
Post by: 3838Derrick on June 01, 2019, 05:55:51 PM

Hi all. I have a 36" genesis racing catamaran and I'm looking to fit it with twin brushless motors.Can anyone recommend what size motors I will need and what size props too.
Thanks, Derrick.
Title: Re: genesis cat
Post by: Martin [Admin] on June 01, 2019, 09:05:53 PM
 
What motor does it come with?

The Aliexpress says:
  Genesis 1122 Catamaran Racing Boat / Electric Brushless RC Boat Fiberglass with 3674 brushless motor KV207, 125A ESC with BEC

HobbyKing:
Spec.
Total Length: 1045mm
Width: 245mm
Height: 115mm
Weight : 2.5kg
Motor: 36-74Size 2075kv Watercooled Brushless Inrunner
ESC: 100A watercooled (Required)
Drive system: 4mm

Video on Utube comment:
 I have since put a Turnigy 4082 1500kv motor + 45mm prop in the genesis, it's very quick now!!
 Approx speed in this video 70km/h, with new setup 85+km/h
Title: Re: genesis cat
Post by: martno1fan on June 07, 2019, 08:53:22 AM
Go onto rc groups theres tons of information on that boat there .https://www.rcgroups.com/racing-boats-electric-57/

Title: Re: genesis cat
Post by: 3838Derrick on June 19, 2019, 12:10:52 PM
Thanks guys. Another question.....Looking facing the transom, which would be the best way to have the props rotating (Port clockwise & starboard anti clockwise or vice versa?
Title: Re: genesis cat
Post by: martno1fan on June 24, 2019, 02:35:55 PM
You need counter rotating props on a twin ,most cats seem to have them spinning inwards so you will need a left and right hand flexshaft and props .
Title: Re: genesis cat
Post by: Tombsy on June 24, 2019, 08:50:19 PM
Always wondered why counter rotating, the twin nitro hydros we run both turn the same direction. Is it to reduce prop walk?
Title: Re: genesis cat
Post by: martno1fan on June 24, 2019, 09:40:04 PM
If both props spin the same way your never going to get the boat running at its best as you will always be fighting prop walk etc . ALL real offshore boats including catamarans run cr props for the same reason .
Title: Re: genesis cat
Post by: Tombsy on June 25, 2019, 12:54:43 AM
I guess maybe the big turnfins on the riggers and only turning right helps. Not like offshore where you have to turn both ways :-) .
 O.P. I built a Genesis with single Leopard motor, I upgraded the strut and flex to 3/16, did some cf reinforcing and I tried the rudder extension but I thought it performed worse in the corners with it and I changed it back.
Title: Re: genesis cat
Post by: 3838Derrick on June 25, 2019, 09:58:09 AM

Thanks again for all your thoughts. I have now fitted left & right flex-shafts and props plus 2X 3674 brushless motors.
Waiting on delivery of 2 esc's ,then I can finally get her into the water!
Title: Re: genesis cat
Post by: 3838Derrick on June 25, 2019, 10:10:13 AM

I think I should explain...
I've had this boat a while now with a single motor and she performed well. Due to eyesight problems, she did encounter some pretty heavy obstacles and ended up pretty much wrecked!!  So I decided to repair her and, as I like building more than I do actually sailing, I've gone with twin motors. Maybe I'm going over the top here (the wife says I am).
The eye problem has been sorted now (cataracts), so I can't use bad eyesight as an excuse for any crashes!
Title: Re: genesis cat
Post by: martno1fan on June 25, 2019, 11:08:15 AM
Lots of people have built the genesis with twin motors twin 36 series motors might be a tad overkill it depends on how many cells each as the boat sits very low in the water as it is so weight can become an issue . I know this from my own experience of my own 36" cat i build , some have done twin setups but most opt for single just because its easier .
Title: Re: genesis cat
Post by: 3838Derrick on June 26, 2019, 10:41:09 AM
I'm going to start with twin 3s wired in tandem. I'll let you know how I get on.