The Prince of Wales presented him with a valuable gold chain as a reward for his attendance. In 1625, Pett, after rendering many important services to the Admiralty, was ordered again to prepare the Prince Royal for sea. She was to bring over the Prince of Wales's bride from France. While the preparations were making for the voyage, news reached Chatham of the death of King James. 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. His patent was sealed on the 16th of January, 1631. In the same year the King visited Woolwich to witness the launching of the Vanguard, which Pett had built; and his Majesty honoured the shipwright by participating in a banquet at his lodgings.

From this period to the year 1637, Pett records nothing of particular importance in his autobiography. He was chiefly occupied in aiding his son Peter—who was rapidly increasing his fame as a shipwright—in repairing and building first-class ships of war. As Pett had, on an early occasion in his life, prepared a miniature ship for Prince Henry, eldest son of James I., he now proceeded to prepare a similar model for the Prince of Wales, the King's eldest son, afterwards Charles II. This model was presented to the Prince at St. James's, "who entertained it with great joy, being purposely made to disport himself withal." On the next visit of his Majesty to Woolwich, he inspected the progress made with the Leopard, a sloop-of-war built by Peter Pett. While in the hold of the vessel, the King called Phineas to one side, and told him of his resolution to have a great new ship built, and that Phineas must be the builder. This great new ship was The Sovereign of the Seas, afterwards built by Phineas and Peter Pett. Some say that the model was prepared by the latter; but Phineas says that it was prepared by himself, and finished by the 29th of October, 1634. As a compensation for his services, his Majesty renewed his pension of 40L. (which had been previously stopped), with orders for all the arrears due upon it to be paid.

To provide the necessary timber for the new ship, Phineas and his son went down into the North to survey the forests. They went first by water to Whitby; from thence they proceeded on horseback to Gisborough and baited; then to Stockton, where they found but poor entertainment, though they lodged with the Mayor, whose house "was only a mean thatched cottage!" Middlesborough and the great iron district of the North had not yet come into existence.

Newcastle, already of some importance, was the principal scene of their labours. The timber for the new ship was found in Chapley Wood and Bracepeth Park. The gentry did all they could to facilitate the object of Pett. On his journey homewards (July, 1635), he took Cambridge on his way, where, says he, "I lodged at the Falcon, and visited Emmanuel College, where I had been a scholar in my youth."

The Sovereign of the Seas was launched on the 12th of October, 1637, having been about two years in building. Evelyn in his diary says of the ship (19th July, 1641):—"We rode to Rochester and Chatham to see the Soveraigne, a monstrous vessel so called, being for burthen, defence, and ornament, the richest that ever spread cloth before the wind. She carried 100 brass cannon, and was 1600 tons, a rare sailer, the work of the famous Phineas Pett." Rear-Admiral Sir William Symonds says that she was afterwards cut down, and was a safe and fast ship.[32]

The Sovereign continued for nearly sixty years to be the finest ship in the English service. Though frequently engaged in the most injurious occupations, she continued fit for any services which the exigencies of the State might require. She fought all through the wars of the Commonwealth; she was the leading ship of Admiral Blake, and was in all the great naval engagements with France and Holland. The Dutch gave her the name of The Golden Devil. In the last fight between the English and French, she encountered the Wonder of the World, and so warmly plied the French Admiral, that she forced him out of his three-decked wooden castle, and chasing the Royal Sun, before her, forced her to fly for shelter among the rocks, where she became a prey to lesser vessels, and was reduced to ashes. At last, in the reign of William III., the Sovereign became leaky and defective with age; she was laid up at Chatham, and being set on fire by negligence or accident, she burnt to the water's edge.

To return to the history of Phineas Pett. As years approached, he retired from office, and "his loving son," as he always affectionately designates Peter, succeeded him as principal shipwright, Charles I. conferring upon him the honour of knighthood. Phineas lived for ten years after the Sovereign of the Seas was launched. In the burial register of the parish of Chatham it is recorded, "Phineas Pett, Esqe. and Capt., was buried 21st August, 1647."[33]

Sir Peter Pett was almost as distinguished as his father. He was the builder of the first frigate, The Constant Warwick. Sir William Symonds says of this vessel:—"She was an incomparable sailer, remarkable for her sharpness and the fineness of her lines; and many were built like her." Pett "introduced convex lines on the immersed part of the hull, with the studding and sprit sails; and, in short, he appears to have fully deserved his character of being the best ship architect of his time."[34] Sir Peter Pett's monument in Deptford Old Church fully records his services to England's naval power.

The Petts are said to have been connected with shipbuilding in the Thames for not less than 200 years. Fuller, in his 'Worthies of England,' says of them—"I am credibly informed that that mystery of shipwrights for some descents hath been preserved faithfully in families, of whom the Petts about Chatham are of singular regard. Good success have they with their skill, and carefully keep so precious a pearl, lest otherwise amongst many friends some foes attain unto it."