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[Iyama]

Ok I'm new to this site, and I just have a few questions I wondered if the community might be able to answer and help me with?

I'll just go over them in brief quickly to give people the jist of it all.

1) how do i wire two motors through one ESC?

2) looking at getting 2 of this motor

Graupner Speed 700 Turbo 9.6V (3308)
Particularly suitable for powerful drive systems of sport model boats of from 7 through 10 cells.
Motor with 5-pole armature, drive shaft diameter 5 mm. Stator ring is standard equipment.

Nominal voltage 9.6 V, Operating voltage range 4.8-14,4V
No-load rpm 15000, Current drain at max. efficiency 12.5A

but what does all that about the voltage and amp usage mean to the more simple amoungst us? (me) as I had thought of putting in a 12v lead acid battery.

I have built a boat before, but it was a while back and with my fathers help, and he's an electrical engineer so he knew what he was doing.
Attached should be a couple of pictures of the hull I've been supplied by a friend.
thanks in advance to anyone who can assist with this

[stallspeed]

Sorry to say, but you narrow your choices of ESC just a bit if you want to run two 9.6 volt 700bb motors.

How big is that boat?

[malcolmfrary]

The lead acid battery would not be most folk's first choice for a boat that looks as fast as that one.  They have been used in the past with what looked like reasonable success, but replacing them with a lighter alternative has invariably shown an improvement in both speed and run time due to reduced weight and the ability to distribute the weight where it is needed.
Add to that, upping the voltage that the motors are rated for by 25% puts you firmly in the "getting away with it" area, and will increase the current as well.  An even bigger ESC wanted.
Actually wiring two motors to one ESC is simple enough - just connect one of then to the ESC output wires, then connect the other across the first.  Making sure that the ESC can handle two motors is another story altogether.  It might be both easier and more economical to use two ESCs each rated for one of your chosen motors.

[Iyama]

Ah I see. so what kind of battery would you recommend? I'm guessing something like an 8 cell nicad or nimh pack?
the boat is approximately 100cm long by 27cm wide and 21cm at its deepest point roughly.
the project is actually being built for a friend of mine, and rather than have the propshaft come out the bottom of the hull he'd like
it to come out of the very back. he seems to think this will give a faster speed?
If I run two esc on two motors the next question would be how do i fix the esc to the reciever to work off one channel of the radio?

[funtimefrankie]

You can buy Y leads to connect the two ESC to one channel from for example

http://www.component-shop.co.uk/

see under leads

[SteamboatPhil]

If you are looking at the shafts coming out of the transom, you will need to go to "surface piercing props", with rudders hanging onto a bracket behind, this also will give you an additional problem as you will need a high torque servo. For the motors you propose to use, I would go with 2 P98 speed controllers (Action Electronics----see this site for details) and 2 x 12 volt 3300 ma NiMh batteries. But looking at the hull, one motor sub surface drive should be enough to get it up on the plane.
I am a humble steam man who has entered the dark world of electrics, but I have been given great advice on my high speed hull, which might be of some use to you------I'm sure fellow mayhemers might give some more hints. Good luck with the project 

[craftysod]

And if your upping the voltage,you will have to think of water cooling as well,to stop the motors cooking
Mark