It won't. If you increase length, beam, and draught by a factor of 10 each, tonnage increases by a factor of 1000. Machinery-power does not increase linearly with tonnage, however, and it should be noted that the machinery used in small attack-craft are either high-speed petrol-engines or high-speed diesels (although by WW2 I think only the Germans had adopted diesels for MTBs) - they are on a different curve than steam-turbines and large medium- and low-speed diesel-engines. Hull-form and -size also matters, as the different portions of resistance have different proportions of total resistance on a small hull than on a large hull - and fast vessels have planing or semi-planing hulls, which do not fit in any way with SpringStyle's formulae.