Hitting the wall...

An interesting feature of powering ships fast is that you can reach a point where the cost in increased SHP to increase speed by a knot is prohibited. I just experimented with this fast battlecruiser type to see if with the maximum SHP, with six shafts, if 39 knots would be possible. The answer is no. The best that can be done is about 38.5 knots. As it is, the ship is designed to be a "hotrod". At least, the ship is pretty well protected for being a very fast battlecruiser (16ft-wide 8in belt, with heavy deck armor).