A five-turret B65 large cruiser is possible but huge

Was a modified B65 with fifteen 310 mm guns in five triple turrets feasible?

It was possible in principle, but only through a major enlargement of an already large design.

The question describes a World of Warships version of B65 with fifteen 310 mm guns in five triple turrets. The historical design study discussed had nine 310 mm guns and a length of 246.2 metres. Reaching fifteen guns would require two more triple turrets, probably one forward and one aft. Lengthening the hull could accommodate them in principle, but the result would be a very large ship with additional cost and redesign work. The game configuration is an enlargement of an unbuilt design, rather than an actual Japanese warship.