This is what is known as a set of linear differential equation, you know some kind of equation, now from there if you can tell how v and r changes with time that tells me whether the ship is going to be stable or unstable, I will discuss that again, but normally what happens, first of all, people write this equation in a non dimensional way, because if you see this equation m etcetera, m is mass of the hull, so it is you know like may be 20000 tons. You may be, you are may something like 15 knots, this becomes all dimensional values.
To make it non dimensional, which makes makes it easier, because first of all remember that all of them must have same dimensions. So, you see m into v dot m into v dot, let us look at the dimension part of m into v dot