Hi Steve, you are really entering the "test and more test" stage now, I have been there many times! I am certainly no expert, but can possibly offer some advice as to what to do. I tried various graupner motors in my 3 foot fireboat, which I know is a completly different boat, and my Huntsman, prior to going to brushless. Unfortunately I have no specific data for the Huntsman, and no video evidence, but used a graupner 700 BB turbo 12v, direct drive, 50mm "x" prop, and ran it right at the top end of the voltage range, 19.2v. Without a cooling coil, the esc kept shutting down, which was a water cooled ripmax seasprint, with cooling coil, things got quite hot, but as the motors are relatively cheap, I thought if I had to change the motor ebvery 12 mo nths or so, then that would be ok. It was a very inefficient set up, but gave pleasing speed for 15 mins flat out.
I am sure that would horrify some peeps, not being able to chug around all afternoon, but thats what I wanted
speed, and more speed, thats why I eventually went over to brushless.
Back to the fireboat, this has video evidence, something that should help you determine what to do. I tried the same setup as above, and also the 8.4 and 9.6v motors. These had very little difference in performance, and I again massively over volted them, I found through testing, to gain some "over scale" speed, you really have to push the volts up on these motors, whilst your motor is 9.6v, the nominal voltage range is up to 14.4v, and you really have to be up there to get any serious performance out of it. THis "on the edge" setup then cascades to the rest of the equipment. You will be pushing big amp draw now, and the esc needs to cope. If it has cooling pipes, use them!!. usually they are ther because the coolling plate is none existant, or inadequate, particularly with the cheap chinese versions. Similar esc's that are used on rc helicopters do not rely on cooling by water (obviously!) as there is a massive airflow over them, our boat escs do not have that luxury.
motor spec:
Nominal voltage 9,6 V
Operating voltage range 4,8 ... 14,4 V
No-load rpm 15000 min 1
No-load current drain 2 A
Current drain at max. efficiency 12,5 A
Current drain when stalled 65 A
Max. efficiency without gearbox 75 %
Length of case, excl. shaft 67 mm
Diameter 42,2 mm
Free shaft length 14 mm
Shaft diameter 5 mm
Weight 320 g
regarding props, they are cheap, getr a couple, make sure they are "x" props, not "s" as they will drive better, I tested over 12!! and was very lucky to be able to borrow a serious collection, plus my own few, and others I had on some other boats. My hunts now has a propshop one, quite expensive, but I tested for almost 2 years to arrive at this, (have you read my build log, loads of info there?) Start small, I would recommend 45mm, and work up in stages. Water cooling is a must, and having a small restriction such as the esc is no problem, hope that helps!
http://s238.photobucket.com/albums/ff100/pmdevlin/?action=view¤t=newshamfulltimemotortests.mp4poor video quality, but you get the idea,