Hi canabus, could you please tell me what brushless motor's you have in your, Sea Hornet,Sea Commander and Sea Queen pelese. I have all three of these as well. Somewhere down the line I will be converting those to brushless. I don't understand all the electrical data myself. I do have a Proboat Miss Geico and she is awesome on the water at full speed. I have purchased the same motor and speed controller as what is in her to put in a new MFA Spearfish that I still have on the shelf in my work shed. I look forward to your set up's.

Hi Andy
Slightly more power with a brushless motor is a no go!!!
Brushless motors the same size are far more powerful !!!
But, the about same RPM a Turnigy L5055-700kv(500 rpm more on a 4S(14.8 volts) Lipo battery would be a good replacement.
Mind you at 1600 watts( about 2 and 1/4 HP) these will used in a large boat like a 46" Vosper Crash Tender or a 46" Sea Queen!!!
My move into brushless motors I have found that they are 7 to 10 times more powerful and equal to, if not better than the old IC motors!!!
My Sea Hornet, Sea Commander and Huntsman run brushless motors .
My Crash Tender is getting the 5055 motor, so it will be interesting to see what it will go like!!

Hi Andy,
what you might call a FAQ!!
Have a look at the info here to help filter the plethora of motor specs and find something close to the MFA850 performance - or better as the brushless motors are more powerful size for size and LiPo batteries much lighter.
http://www.thercmodelboatforum.com/t1234-brushed-to-brushless
As a guide here is a table of the Graupner brushless specs for you to compare with the 850 spec.
There is no conversion table as such, especially since with many brushless and ESCs you can alter the performance by adjusting timing at the ESC! Turbo!!
Happy hunting, cheers Doug 😎