David Lilley left school in the mid-1970s with A levels in mathematics, physics and chemistry - a combination that pointed towards a career in either medicine or engineering.
"I thought I wouldn't be able to cope with the sight of blood," Dr Lilley said. So engineering it was.
"I now know that it wouldn't have been a problem for me, and if I'd had the opportunity to go into an operating theatre, I probably wouldn't have been an engineer at all."
Dr Lilley, senior lecturer in structural engineering at Newcastle University, has seen his share of bloody injuries in his other life as a volunteer lifeboatman with the Royal National Lifeboat Institution.
He also had occasion to use his first-aid expertise in the university: a student recently collapsed in his class and he was able to look after her until an ambulance arrived.
"I don't think it was my lecture that did it," he said.
Dr Lilley grew up in Redcar on the Yorkshire coast and was a keen sea fisherman in his teens, a hobby he had to abandon while pursuing a BSc and a PhD at the University of Bristol. But when he took up a lectureship at Newcastle, he and his wife settled beside Cullercoats Bay.
Buying a boat was a higher priority for them than a three-piece suite, and Dr Lilley was rapidly recruited by the Cullercoats RNLI as a volunteer crewman. He later moved to the Tynemouth station, where he is navigator aboard the Spirit of Northumberland. He has just won a special award for 20 years' service.
One of his most memorable rescues was in 2006, when he was called out at midnight to navigate the lifeboat 75 miles out to sea to help an injured Danish trawlerman because electrical storms prevented Royal Air Force rescue helicopters from taking off.
Radio contact with the shore is lost beyond 30 miles, and the lifeboat had been sailing for three hours at full speed before it picked up a faint blip on the radar.
"There was enormous relief."
Dr Lilley's expertise in maths and engineering is crucial to his skill as a navigator.
"Structural engineering is based on logic and principles of cause and effect. The same thing happens when you're out at sea," he said. "An ability in maths and geometry (and an) understanding of physical concepts are useful (because they can help) to predict tide times, and what happens when a boat's drifting."
He dismisses the view that his lifesaving work is hazardous. The last RNLI crew to be lost was that of the Penlee lifeboat Solomon Brown in 1981, and Dr Lilley said the boats today are much better.
"It's not a big risk if you're properly trained. You've got more chance of being run over crossing the road than being hurt in a lifeboat."
At the age of 53, Dr Lilley is restricted to the large all-weather lifeboats because there is a retirement age of 45 on inshore boats.
"In the small boats, you pick up a few bruises and grazes, and the aches and pains don't go away quite so quickly when you get older."
But he has been seasick only twice in 20 years, once after being called out in the early hours of Boxing Day - "I was full of nice Christmas food."
The second time was in rough seas 22 miles offshore, searching for a yacht in trouble and poring over charts in the wheelhouse, which is full of diesel fumes. "Most of the lads don't like being navigator because it's confining, and it can make you feel quite ill."
He said he was dismayed by the scant regard many people have for sea safety. One SOS came late one Saturday night from a group who had gone out in a speedboat and got lost in thick fog.
"They didn't know where they were. They thought they were south of the River Tyne, and they could hear some traffic. I was navigating that day, and it was a case of identifying all the various signals we were getting on the radar," he said.
"We were getting echoes off seagulls. We were chasing shadows. When we got to them, the youngest was ten, the eldest was 22. None had lifejackets, and the only light they had was from a mobile phone."
Dr Lilley said his students are aware of his RNLI work because of the pager he wears on his belt, but it has led him to cancel lectures on only a couple of occasions: once when he was searching 250 square miles of sea for a missing fishing boat.
"It very rarely interferes, and I think everybody understands. It's no different from me going down with flu."
Several of his students have helped raise funds, and he pointed out that the RNLI, which is supported solely by voluntary donations, spends £300,000 a day on lifesaving work.
But he denied that the RNLI offered excitement that would otherwise be missing in academic life.
"As a structural engineer, I get involved with local industry, and I get a bit of excitement in site visits. I don't spend all my time with my nose in a book."