so where it says MAX_SPEED do i put the fastest speed i want it to go. and does this also make it so it cant stop?
MAX_SPEED is a global variable. In my mission, as the boats would enter certain parts of the river, they would hit a trigger which would change this variable. That way I could speed up and slow down the boats depending on how far along their preset path they had gone.
I'm not sure if this would work in your mission or not. The best thing you can do is to just plop it down into your mission and give it a go.
One more thing I should mention is that by changing the bolded number in the line below, you can increase the acceleration (increase the number) or decrease it (decrease the number):
_boat setvelocity [(velocity _boat select 0)*
1.1, (velocity _boat select 1)*
1.1, (velocity _boat select 2)]