The opinions expressed by the above writers[13] indicate for us in general terms the chief particulars in which the ships of this period fell short of naval requirements. They were designed without knowledge of the laws governing the strength of materials, stability, and the motion of bodies through water; they were built without adequate supervision, frequently of green timber badly scarphed or cut across the grain, and were overburdened with ordnance. Their holds were cumbered with large quantities of shingle ballast which tended to clog the limber-holes of the bilge and rot the frames and floor timbers; while the stowage space amidships was further usurped by the cook-rooms, which were placed on the shingle, and which, by the heat radiated from their brick sides, did damage to the timbers and seams in their vicinity. Vessels were rarely sheathed. Though John Hawkins had devised a system of sheathing by a veneer of planking nailed over a layer of hair and tar, it was only to ships going on special service in seas where the worm was active that sheathing was applied. Sheathing possessed, then, some significance. In 1620, for instance, the Venetian ambassador reported to his government the discovery that some of our ships were being sheathed, and from this fact deduced an impending expedition to the Mediterranean. With the navy in the depths of neglect and with shipbuilding in the state described, Phineas Pett began to impose his permanent mark on design and construction. The mechanism by which he secured his results, the calculations and methods and rules used by him, were veiled in profound secrecy, in accordance with the traditions of his profession. He began by new-building old ships of the Elizabethan time, giving them an improved form so far as practicable. His friend and patron was the young Prince Henry, for whom in 1607 he made a model which the king greatly admired. And shortly after this, in the face of much jealousy on the part of his rivals, he laid down by command a new great ship--the _Prince Royal_, of 1187 tons, with a breadth of 43 feet and a keel length of 115 feet, double-built and sumptuously adorned, in all respects the finest ship that had ever been built in England. She carried no less than fifty-five guns, her general proportions were of a unity, and her strength was of a superiority, far in advance of current practice. In strength especially she marked an advance which yielded benefit later, in the wars with Holland. She was double planked, “a charge which was not formerly thought upon, and all the butt-heads were double-bolted with iron bolts.”