Have now found the video and posted to Video Gallery
Dave

Good point Dave ...seem to recall a 50 mmwaterjet by graupner did have a max motor size and a ic equivalent when I looked it up previously.....Not straight forward then.

Hi Steve
Plenty of suggestions being made. I use waterjets and you should be aware of the max revs quoted by the manufacturer. You exceed this figure at your own risk.
I agree with the previous comments regarding brushless delivering far more power if powered by Lipo.
Ballast is a crucial part of the equation and the Sea Breacher has a large volume of air in its hull which makes it very buoyant. Like a sub perhaps some form of ballast tank that can be vented may be worth considering.
You really need to speak with someone who is into submersibles as they have the experience and knowledge of how best to proceed.
The Model Boat Convention is on next weekend and they sometimes have submariner modellers in attendance.
Good luck
Dave

Great feedback guys looks like going for a brushless motor is the way to go....going to cost a bit for the upgrade so Im researching it first to get it right...

Hi Steve
The Graupner Speed 900BB Torque specs are 6-40 volts, 6,500 rpm, 54A amps, shaft 6mm, dia. 51.5 mm, length 95mm and weight 645 grams.
A brushless motor like the Hobbyking L5055 600kv is 11.1- 22.5 volts(3S -6S) power 1500watts, 55 Amps, shaft 6mm, dia. 50mm, length 55mm and weight 311 grams.
On 3S=6660 rpm, 4S=8880 rpm and 6S=13500 rpm.
The brushless motors are far more powerful and with an ESC with handles up to 6S(22.5 volts) you would have rpm's to drive
a water jet unit.
Canabus

I think I would be tempted to go brushless with it. Far more power for the size of motor. I don't think an 800 brushed motor would have the revs to push much water through a 50mm jet unit. Even an 850 motor would be an improvement. But going brushless, you could get far more revs out of it. Best of luck with your endeavours, Dave W 😀

Hi Steve. I understand that the original ran with a 900 motor but you have only an 800 fitted, correct?
Might explain some of your apparent problem!
Cheers Doug 😎

Just tried seabreacher on the lake everything working fine but its underpowered at the moment....suggestions for hardware updates welcome guys 😀