Krishna,
I think you will find that you're model won't turn at all, or at least will hardly turn.
She will probably move sideways instead.
That is because your thruster is pretty much midships placed, and as there's only 1 thruster there is no momentum, and it's a momentum that makes a vessel turn.
You'll need to add 1 thruster (maybe behind or in front of the original thruster as moving the current 1 will probably be next to impossible), and otherwise you'll need to live with the fact that this model won't turn at all, in which case I would recommend adding a large rudder-like keel at the stern to keep her going straight, rather then being steered by the wind.
The second thruster probably doesn't need to be this big and powerful, as it's main purpose is to steer the vessel.
You could make a rudder with a small, but long motor in it with a propeller in a "tunnel" (don't recall the proper English name, it's basically a short tube around the propeller, it's mostly used in tugs as it gives a certain propeller some extra efficiency, and therefore more power), that would give it enough power to steer the vessel (though you'll need to keep the main thruster amidships when steering, as you'd otherwise steer whilst moving sideways).
Or a large rudder under the stern could do the job as well, though it must be placed as far to the end of the vessel as possible, but as it's not so much in the propellers thrust (especially not when turning) it needs to big as the rudder mostly needs the water from the propeller to give some steering power.
Therefore a propeller fitted to the rudder would give that much more result, though it does require 1 or 2 more channels on the radio.
Greetings Josse