hi there Kenny
No radios are allowed (as far as I know) in the straight line models. There are several classes in the straight running.
I believe there is the 'wedge-shaped class' - the boats (as they suggest) are shaped a bit like a wedge.
There is an 'off-scale' section as well - where a boat can represent a warship, cabin-cruiser etc.
Im not sure about the propulsion side of it, because I have seen a petrol engine in the same competition as a steam-powered vessel.
I know the scoring is fairly simple, its basically like a dartboard, only with a set of goal posts. The goal posts are set narrowly in the middle say 10 feet apart, next set of poles on the outside of those poles say another 10 feet away from them and soforth and you get points for getting into the middle of them - say if you got between the two middle ones that's the bulls eye and you get top marks - if you hit the next set of posts out, the points decrease etc., and so it goes.
Dont think there is a time limit on it.
The Rudder is fixed with microscopic adjustment of only 1/8 inch (for arguments say) movement either side of the centre.
This adjustment is just to allow for windage, and tork of the propellers.
aye
john e
bluebird
hope this sheds a bit of light on it for you 
Kenny, no points if your tug sinks in the middle of the course
