This rotation question seems to pop up regularly.
Probably for a model, rotation direction doesn't really matter, but one authoritative answer can be found here:
http://modeltugforum.com/index.php?topic=5947.0, which quotes from the Ship Handler's Guide.
To summarise the comments:
Outward-turning propellers means the blades of the propellers are outward turning in the upper half of their circle of rotation, and, when viewed from astern, the propeller with the right-hand blades is on the starboard (right) side and again, when viewed from astern to drive the boat forward, it must rotate in a clockwise direction.
This is the preferred arrangement on full-size ships because when using the props to assist a turn, i.e one prop pushing ahead and one pushing astern, the side thrust from the two propellers assists the turn.
The attached image from www.slideshare.net may help.
Roy