Short cutoff is difficult for starting an engine, and when maneuvering and starting the engine, "full gear" (long cutoff) is generally to be used. After things get rolling, the operator can apply the common railroad practice of "linking up", and the cutoff can be reduced. The calculations previously presented show that the engine can make enough power even with short cutoff, as well as the low main steam pressure originally stated by Whistledoc.
The proposed engine and boiler are certainly capable of much more power with higher steam pressure and longer cutoff, but of course the hull will not permit much more power to do anything in making the boat go faster.