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[treeboa]

hi guys, right this is not as such a model boat enquiry, its similar being a twin motor bait boat, shes a cat hull with a pair of 2345 grapner water jets in it, i purchased it part built, when shes finished the hull halfs will be bonded with silicone and not easy accesable - needs to be waterproof as far as poss

as purchased she has a pair of mfa.como drills 457/re380, 3-7.2v motors in it, i have however two pairs of other motors, one pair, vision400 marine motors ( mtroniks) 4.8 -12v high torque and a pair of multiplex permax 400`s ( #332548) 7.2 v

i have the choice of a pair of lead acid 6v 1.2ah ( came with baitboat)  or a pair of 7.2 race packs - to be purchased if needed

the cats hulls are 24 inches by three inches each, speed for me is not the main interest, carrying of a couple of K of bait and a decent run time is,  the water jets drives are powered via a pair of 28mm props

can any one offer me advice which is the better motors to have fitted, also which battery packs, i intend using one per motor, two esc with a mixer circuit to control the forwards/backwards and steering from one stick ( already have this in and tried)

current wieght of the boat is 2.287kg, i still have the hopper doors ro put in but imagine the all up wieght will be a ax of 3kg

thanks in advance

[Roadrunner]

Personally i would go with a pair of grapner 400's as the motor source powered from a single ESC (15A should be more then adequate for both motors) and run from a 6v 4.5AhLA battery, your looking at run time of 2 hours at a rough guess, so for a days use should be fine with only a spare battery or two.

That's how i would look to do it but obviously the 7.2v would work also but would require either a 2nd esc or wire up the battery's in parallel for longer endurance.


You want to make sure you have enough power to get out of trouble so Grapner 400 bb motors may be better, when hitting 540-555 size motors your looking at a max of 11A draw from each so your battery would only last 15-20 mins at tops with a 7.2 or 6vLA , so please bare that in mind if you think a bigger motor is what you may need. 'jet drive' units do provide a lot of thrust so using smaller 400 sized motors will give you a lot of ompf! 

[treeboa]

has to be on two esc`s as the steering is controlled by each drive, no buckets on it as no room being fitted by the former part builder, tested in a paddling pool and running in reverse does give enough back flow to reverse the boat, so the mixer will work well enough for tight steering

trouble with high ah lead acids is space, plus wieght, so i may be forced in that to use a high capacity pair of `race packs` which wiegh in at just slightly heavier than the graupner 6v 1.2ah lead acids it was supplied with

thinking further from advice i may be better joining the batteries rather than use one per motor, that way both motors are getting the same voltage as the power is used up

[john s 2]

Might be worthwhile looking at Actions P94 mixer/esc.Its two Esc,s with full mixing.All in one. Ive got a couple
of them, and with one motor full ahead, and the other in reverse. I can tun my lifeboat in its length.John. 

[Roadrunner]

A P94 would do the job nicely, and would give the boat tank steering off a two channel system which is less complcaited, this also eliminated the use of two batterys as the P94 can use a single battery quite happily for two motors,

If your using 400 size motors then I think the action P94 Lite (which is a twin 10A esc) would do the job rather then the standard P94 which is a twin 20A esc.

http://www.action-electronics.co.uk/mixers.php

I can only suggest contacting Dave at ACTion and see what he suggests, hes the man to talk to 

[treeboa]

i have a mixer unit already, decided to get the solder tags and make my own 4600mah 7.2v pack up, three cells a side so she stays balanced