Tyrrell, John (‘Jack’) (1905–88), naval architect, was born 16 June 1905 in Arklow, Co. Wicklow, son of Michael Tyrrell (qv), shipbuilder, and Mary Tyrrell (neé Abraham). Since at latest the 1770s, generations of Tyrrells had owned, skippered, or built ships in Arklow. In 1864 Jack Tyrrell's grandfather established the shipbuilding firm of John Tyrrell & Sons Ltd. The first state-operated nautical school was opened in Arklow in September 1930 and Tyrrell, a qualified naval architect (AMINA), gave instruction in ship construction. By the mid 1930s he was involved in the design of inshore fishing vessels for the Sea Fisheries Association (later Bord Iascaigh Mhara (BIM)). In 1943 he designed the ‘Tyrrell bow’, which flared upward from conventional water level, giving fishing-boats increased buoyancy and manoeuvrability. Throughout his career, he designed yachts, harbour launches, passenger ferries, and special service craft such as tenders and pilot-boats.
A founder member of the Maritime Institute of Ireland (1941), he had an international reputation. While continuing to supply boats for BIM, he designed and built fishing vessels for British owners and the Jamaican Department of Fisheries in the mid 1950s. He was the Irish delegate at the 1959 UN Food and Agriculture Organisation (FAO) conference in Rome on the design and performance of fishing vessels. In September 1959 he built for Sir Francis Chichester Gypsy Moth III, a 40 ft (12.19 m) racing cutter with 650 sq. ft (60.4 sq. m) of sail and a 14 h.p. engine, which won the inaugural transatlantic solo yacht race in 1960 and again in 1962. At the 1963 UN FAO fishing vessels conference in Gothenberg he again represented Ireland. In June 1964 he won the Royal National Lifeboat Institution (RNLI) competition for the new 70 ft (21.3 m) Clyde-class offshore lifeboat, designed for operation in poor harbours where no lifeboat was stationed. His prototype had a speed of 11 knots and a range of 650 miles (1,046 km). He was the first chairman of the Irish Boat Builders Association (1964) and the first Irishman to be elected fellow of the Royal Institute of Naval Architects (1965) – although John Corry (qv) had been a trustee of property of the Institute and its honorary vice-president. Tyrrell's sloop Tyauldur, designed and built at a cost of £10,000 and shipped to New York in 1967 for sea trials, crossed the Atlantic from Nova Scotia to Kinsale, Co. Cork, in July 1968 in fourteen days, skippered by Rory O'Hanlon, commodore of the Royal St George Yacht Club, Dún Laoghaire.
Tyrrell was the first president of the Irish Federation of Marine Industries (1970) and received (1971) the Naval Association's Asgard Award for outstanding services to the maritime community in Ireland. Even as Tyauldur docked in Kinsale, the old gun-runner Asgard, then an Irish Department of Defence sail-training vessel, was given one last restoration. In November 1973 he prepared designs for a replacement vessel, which he submitted to the Department of Defence in January 1974. The design was similar to that of his late uncle John's Lady Avenel, which he had sailed on as a boy. In 1977 he was commissioned by the Irish government to build the 84 ft (25.6m) brigantine Asgard II, for a crew of twenty-five, at his Arklow shipyard. The first sailing vessel constructed in Ireland for sixty years, and Jack Tyrrell's masterpiece, the Asgard II was launched by the taoiseach, C. J. Haughey (1925–2006), on 7 March 1981. Tyrrell then served on Coiste An Asgard, the training vessel's governing body. On 29 October 1981 he was made an honorary life member of the Maritime Institute of Ireland in recognition of his exemplary services for and on behalf of Irish maritime affairs.
Tyrrell was also active in promoting the port of Arklow. A member since 1946 of Arklow harbour board, he was vice-chairman and twice chairman, and remained a board member till 1988. He realised his ambition to see Arklow become a port of registration, and was president of Arklow chamber of commerce 1956–7. He succeeded his father as secretary of Arklow RNLI station (1951–78) and was a major driving force behind the Arklow Maritime Museum, opened in 1976. He was appointed first chairman of Arklow Shipping Ltd (established 1966), which had, by the year of his death, a fleet of nineteen merchant ships. Arklow Engineering Services Ltd, of which he was also a director, employed seventy-five people in boatbuilding and repairs. He was also associated with the Arklow firms of Bay Shipping Ltd (established 1971) and Vale Shipping Ltd (established 1972). His wife Aileen (neé Murray) died in April 1988. In May he was invited to the launch of Dyflin, a replica viking longship, in Dublin port. He had advised the Dublin shipwrights on its design and construction. Jack Tyrrell died 29 July 1988 at his Arklow residence and was buried at Arklow new cemetery. The Asgard II returned to Dublin port from an Australian trip that day. He was survived by one daughter, Dorothy, and three sons – Michael and James, who worked in the family business, and John, Arklow harbourmaster in 1988. On 7 August 1988 the president of Ireland, Dr Patrick Hillery, launched the Arklow training yawl Ógra na Mara, designed by Jack Tyrrell and built by local FÁS trainees.