DONALD McCallum, who has died aged 69, worked on some of the US Navy's most prestigious projects as a ship designer, and later in life became something of an adventurer in Scotland.

McCallum was born in Campbeltown, which was then a busy town with a coal mine, distilleries, farms and a shipyard, where his father worked. McCallum's father volunteered during the Second World War and, after surviving Dunkirk, he died in 1943 in Syria when his tank plunged into a river. The widowed Amelia was left with two young children, Barbara and young McCallum, in Campbeltown. Many years later, McCallum visited his father's grave in Syria.

Early education for McCallum was at Millknowe school under the daunting Edward Pursell, and later at the grammar school, where McCallum excelled in technical subjects. His mentor there was Donald Leys, who recommended that he pursue a career in architecture. This led to further studies at Glasgow Royal College of Science and Technology, with McCallum graduating in 1959 as a naval architect.

Summers, however, were spent in Kintyre, where McCallum's sporting prowess saw him completing each summer on the Highland games circuit with some degree of success.

McCallum then joined the famous Glasgow shipbuilding firm Stephen & Sons, where, under the redoubtable "Doc" Watson, his skills came to the fore in ship design. Ships McCallum worked on included the MV Princess of Vancouver and MV City of Newcastle.

But to further his career, McCallum then moved to Canada, joining Davie Shipbuilding in Quebec, where he helped design destroyers. While working with Davie Shipbuilding, McCallum met and fell in love with a young French-Canadian girl, Lise Boucher. They married in St Antoine de Bienville in 1963 and the marriage saw Lise share experience of 44 years of happiness sharing her husband's pursuits.

With his Kintyre thirst for travel, however, McCallum and Lise moved to Seattle, taking up posts with Spaulding Associates and Todd Shipyards, working on the design of the US Navy ship Hayes.

Then came the dream move for McCallum, when he was invited to join Navsec (Naval Ship Engineering Centre) in Washington DC, which meant a return to the east coast with Lise and, by now, his young family. Sponsored by Navsec, McCallum also attended the University of Michigan, where he obtained a masters in naval architecture.

During his time with the US Navy, McCallum was involved in the design of many famous ships - some of these now household names. He represented the US Navy at gatherings around the world, presenting papers and giving lectures which culminated in receiving the Navsec Naval Architect of the Year award in 1981.

After retiring, McCallum continued with the US Navy as a consultant, still receiving accolades as recently as last year, when he won an award for his design of the hull of the US Navy's latest supply ship, USN Lewis & Clark. McCallum and Lise were guests at the launch in San Diego.

After retirement, McCallum's next life took off when he renewed his schoolboy friendships in Campbeltown with Kenneth Colville and Roddy Lightbody by making annual three-month trips to Kintyre, when the trio immersed themselves in yearly adventures.

McCallum's first trip took him to Syria, where he sought out his father's grave, followed by a visit to the Holy Land accompanied by Mr Lightbody. During a visit to Kintyre in 2002, McCallum told his friends that the following year he was going to recreate the voyage made by St Columba in 563AD from Ireland to Iona. So he began a year-long series of e-mails and telephone calls as an international crew of rowers were recruited to undertake the hazardous voyage under his leadership. Finally, in 2003, the curragh named Colmcille left Portrush for Iona. McCallum followed this with a trek in 2004 through the Great Glen, recreating the pilgrimage of St Columba to King Brude's Fort in Inverness.

Other adventures saw McCallum row single handedly through the Forth and Clyde Canal, carrying a framed message from the Cathedral of New York to St Mary's Cathedral in Edinburgh thanking the Scottish people for their support after 9/11. Then, in 2005, with Kenneth and Roddy, he completed the formidable Christian pilgrimage Camino de Santiago, from the Pyrenees to Santiago de Compostela in Spain.

Even in the past year, while ill with cancer, he was planning to accompany Kenneth by retracing the footsteps of their favourite childhood author Arthur Ransome by sailing on the lakes in the Lake District made famous in the Swallows and Amazons series.

Donald McCallum is survived by his wife, Lise; children Martine, Carole, Suzanne and Andrew; and his grandchildren Domenique, Nicole, Gabrielle, Sean and Natalie. Also by his sisters Barbara, Carol and brother Angus Martin, the Kintyre author and historian.

Donald was compassionate, understanding and always concerned to help people share the spirituality that buoyed him so colourfully through his life. That he was so reticent in trumpeting his own professional achievements only helped to underline his humility and integrity.

Donald Nicholson McCallum was a proud Scot and a true son of Campbeltown. St Columba would have been proud of him. He is sorely missed.

A packed St Andrew's Church in Washington DC of family and friends attended the funeral of Donald McCallum on June 7, ironically only two days before the Day of St Columba and four years since Donald led the voyage in a curragh from Ireland to Iona, recreating the famous Saint's epic voyage. A Remembrance Service conducted by his friends Rev Forrest and Rev Harris will be held at St Columba's Footsteps, Southend, on September 22, to which all his family and friends in Kintyre, along with crew members of Colmcille, are invited.