At the accession of James I. in 1603, Pett was commanded by the Lord High Admiral with all possible speed to build a little vessel for the young Prince Henry, eldest son of His Majesty. It was to be a sort of copy of the Ark Royal, which was the flagship of the Lord High Admiral when he defeated the Spanish Armada. Pett proceeded to accomplish the order with all dispatch. The little ship was in length by the keel 28 feet, in breadth 12 feet, and very curiously garnished within and without with painting and carving. After working by torch and candle light, night and day, the ship was launched, and set sail for the Thames, with the noise of drums, trumpets, and cannon, at the beginning of March, 1604. After passing through a great storm at the Nore, the vessel reached the Tower, where the King and the young Prince inspected her with delight. She was christened Disdain by the Lord High Admiral, and Pett was appointed captain of the ship. After his return to Chatham, Pett, at his own charge, built a small ship at Gillingham, of 300 tons, which he launched in the same year, and named the Resistance. The ship was scarcely out of hand, when Pett was ordered to Woolwich, to prepare the Bear and other vessels for conveying his patron, the Lord High Admiral, as an Ambassador Extraordinary to Spain, for the purpose of concluding peace, after a strife of more than forty years. The Resistance was hired by the Government as a transport, and Pett was put in command. He seems to have been married at this time, as he mentions in his memoir that he parted with his wife and children at Chatham on the 24th of March, 1605, and that he sailed from Queenborough on Easter Sunday. During the voyage to Lisbon the Resistance became separated from the Ambassador's squadron, and took refuge in Corunna. She then set sail for Lisbon, which she reached on the 24th of April; and afterwards for St. Lucar, on the Guadalquiver, near Seville, which she reached on the 11th of May following. After revisiting Corunna, "according to instructions," on the homeward voyage, Pett directed his course for England, and reached Rye on the 26th of June, "amidst much rain, thunder, and lightning." In the course of the same year, his brother Joseph died, and Phineas succeeded to his post as master shipbuilder at Chatham. He was permitted, in conjunction with one Henry Farvey and three others, to receive the usual reward of 5s. per ton for building five new merchant ships,[21] most probably for East Indian commerce, now assuming large dimensions. He was despatched by the Government to Bearwood, in Hampshire, to make a selection of timber from the estate of the Earl of Worcester for the use of the navy, and on presenting his report 3000 tons were purchased. What with his building of ships, his attendance on the Lord Admiral to Spain, and his selection of timber for the Government, his hands seem to have been kept very full during the whole of 1605.