Pett was afterwards commanded to go forward with the work of preparing the Prince Royal, as well as the whole fleet, which was intended to escort the French Princess, or rather the Queen, to England.

The expedition took place in May, and the young Queen landed at Dover on the 12th of that month.
Pett continued to be employed in building and repairing ships, as well as in preparing new designs, which he submitted to the King and the Commissioners of the Navy.

In 1626, he was appointed a joint commissioner, with the Lord High Admiral, the Lord Treasurer Marlborough, and others, "to enquire into certain alleged abuses of the Navy, and to view the state thereof, and also the stores thereof," clearly showing that he was regaining his old position.

He was also engaged in determining the best mode of measuring the tonnage of ships.[31] Four years later he was again appointed a commissioner for making "a general survey of the whole navy at Chatham." For this and his other services the King promoted Pett to be a principal officer of the Navy, with a fee of 200L.

per annum.