Dave, the type or size of the model doesn't really matter. As long as the radio is a suitable frequency for boats, and the 6EX is a 2.4 GHz set so fine, and as long as the range is suitable, again the 6EX will go beyond most of our eyesights, then it would be suitable for your boat. Assuming that you do not require more than four proportional and two switched channels, which few of us require then that radio would be fine for your trawler.
A common arrangement for such a radio would be to set it up with the left hand stick up and down as the throttle with forward pushed up and astern pushed down with a spring to centre action, and the right hand stick used to go from side to side for left to port and right to starboard, again sprung to the centre position. You then have two proportional and two switched channels remaining for any auxiliaries you might want to control.
It might be worth having a read through this report here:
Futaba 6EX
Try sending Kev a personal message.