HI grace
Just Googled deben tracer. Not a cheap option by any means. For the prices quoted you could convert to Brushless and LiPo with charger.

hi, if you have a look at deben tracer lithium batteries..they do a 24 amp battery that weighs less than a pair of 7amp pb's.....the deben battery is 12v and deep cycle

Glad to have been of help.

You can use your Nimh batteries with a brushless set-up. May not be as fast or last as long and also be a bit heavier but still better than a brushed motor.

Brushless rev so much faster than brushless and using a smaller prop will allow their full power to develop.

I still believe you should try your geared Graupner and see how it goes. if it looks right to you then no need to venture into new technology until you want more speed.

Good luck 😀

I totally appreciate what your saying as I am new to this in all fairness and have read and heard some bad stories about lipos if you don't know what your doing .
in my other boats Ive used 8.4v or 9.6v 5100 ah nimh and have had great results
really I would like to stay with a brushed motor if I can get one that will give me the power I need I don't want it to leave the water I like my boats to be to scale.
I had a 48 huntsman with a torpedo 850 50x prop but it was so under powered
really thinking about it maybe I should of gone for the smaller sea commander
thanks for your help and advice

HI daveo
You won't be disappointed. I was unaware Mtroniks were now supplying brushless ESC's but am aware their brushed range has been updated to support Lipos.

Sorry if this is teaching you to suck eggs but Lipo's are not any where near as tolerant as NiMh's and you must use a balanced charger to prevent overcharging.

The ESC will have a setting to cut the power when an individual cell voltage reaches 3v or current thinking says 3.3v. Better LiPos usually give guidance.

Ignore these limits at your peril. if you visit You Tube you will find videos of what can happen.

It would be very useful if you would share your experience with the web members.

Good luck 😀

cheers mate I think it will be brushless as don't want the weight of a big motor and 12v lead acid battery go brushless and lipo mtroniks doing a good 50amp combo for £109
cheers

HI daveo
If you want speed then brushless will give the best result.
Large prop will need a big motor or a geared motor. As you have a geared Graupner I would try this and see how the model performs. You may need to watercool the motor and ESC.
If the speed is too slow you can decide whether to try a bigger brushed or go brushless, both will cost you money but the latter will give the fastest speed. A brushless will also need a brushless ESC. Giant Shark have suitable setups.
Good luck and please share your experience with further posts 😀