When the rest of the lifeboat crew tell Kirsten Hastie she’s “one of the boys”, it’s the greatest compliment they can pay her.

The Aberdeen teacher at Robert Gordon’s College joined the Royal National Lifeboat Institution crew in Dunbar when she was a schoolgirl aged 17. Now, 11 years on, the dark-haired PE teacher is the only woman in the Aberdeen lifeboat crew braving dangerous seas in sometimes treacherous conditions.

“I joined originally, I suppose, because I have always used the sea - I’ve been a kayaker and a surfer, and my mum and grandmother have been involved in fund-raising for the lifeboat station in Dunbar,” says Kirsten, 28, as the lifeboat builds up speed along the coastline.

“I carry my pager with me and my school has agreed to let me out. Being a PE teacher, or any sort of teacher, there’s an aspect of safety, in that you can’t abandon a class in the swimming pool or in a gym. But being in a big department, there are people around to step in and cover fairly quickly, which allows me to get down to the station.”

This morning the crew is on exercise on the Severn-class lifeboat “Bon Accord”, practising man overboard drills and working with the Y-boat it carries on board, and another inflatable. It’s a fine day with more favourable conditions than they are used to when pagers go off.

“There haven’t been that many during school. There are sometimes shouts which you are called out to during the night and I don’t make it into school in the morning. So it’s just a phone call into work to say I won’t be in until later. They’re good about that,” says Kirsten.

Like most people who put their lives on the line for others, Kirsten understates the dangerous conditions she works in. But one particular rescue she does remember was when she ended up in the sea. “It was an incident at Dunbar, where a yacht had gone aground into the harbour entrance. A swell tends to run round the corner of the harbour entrance and the offshore vessel there is launched from Torness Power station, where it’s kept.

“It wasn’t a rough night but there was a heavy swell running into the harbour entrance. It was about eight or nine in the evening, so the inshore boat, which is kept at the harbour, was launched as well.

“While attempting to take the yacht off the rocks at the harbour entrance, our boat capsized because the line became entangled with one of the rollers that came around the corner. We ended up swimming - there had been three of us in the boat, so we managed to swim it out beyond the breakers and right it and get it going again.

“Our first attempt to get the crewman off his yacht had failed, as he didn’t want to leave it. That had left us with no choice. A lot of the time you wouldn’t bother trying to pull a yacht off with a small inshore boat, but he was in danger and wouldn’t come off. The offshore vessel arrived and saved the day.”

Another incident involved a large cargo ship, reported running aground in a very heavy swell. “We had to first of all get out to the boat, which is kept on a mooring there - that was difficult,” she says. “It was a case of everybody inside the lifeboat being strapped in, because the boat was almost on its side. That’s probably one of the worst times in terms of weather, although, as we got to the cargo ship, it managed to get its engines going.”

Confidence in the lifeboat and the other volunteers helps Kirsten keep her nerve: “You have got to have respect for what you’re doing and for the sea as well, and the force of it,” she says. “But at the same time I place a lot of confidence in the lifeboat itself and in the crew I sail with. Because the offshore boat is self-righting, you do tend to go out in all sorts of weather.”

Also on board the “Bon Accord” is Jo Horne, 37, who works for a company involved with shipping. “I love the boat and I want to help,” she says.

Jo is observing today but hoping to boost the female contingent on the Aberdeen lifeboat. Behind us, one of the crew has slipped into the chilly North Sea, as they practise “man overboard” drill.

Another volunteer, Jim Wilson, 49, signed up after his nephew was lost at sea: “He was lost fishing down here and that’s what made me join the crew. These guys were out for days looking for him. He was 17,” says Jim, a painter and decorator.

There are 16 in the Aberdeen team, operating in the North Sea between Stonehaven and Peterhead and beyond when needed.

A little further down the coast, Alison Couch, 25, is a grateful customer who became a volunteer education speaker for the RNLI after the Islay lifeboat rescued her from Scotland’s notorious whirl-pool Corrievreckan. A nature reserve warden at St Cyrus, she was teaching a friend and his three children to sail with her boyfriend off the West Coast of Scotland, when their yacht developed engine trouble and caught fire.

The wind had dropped and the engine made a strange noise when they switched it on: “Then we saw lots of white smoke billowing out from down below. My boyfriend managed to put the fire out with a fire extinguisher, but it left us with no engine and no wind, so we couldn’t sail and were still within the reaches of the Corrievreckan, which stretches for something like 12 miles.

“So when the tide changed, we were going to get sucked back into the whirlpool, which is not a good idea without power. If it had been anywhere else we could have sat and waited for the wind to come back, but a big whirlpool is something you don’t really want to mess around with.”

Alison and her boyfriend have worked as professional sailors and knew they had to alert the Coastguard for help. With no other boats in the vicinity to assist, the Islay Lifeboat was called out and towed them back to safety. Now Alison gives regular talks to schoolchildren in her community about the work of the RNLI.

At Britain’s most northerly lifeboat station in Shetland, Jim Nicolson has given a lifetime’s voluntary service to the RNLI. He joined the lifeboat crew at Aith nearly 40 years ago, the year after he began his teaching career. The station was founded in 1933 and crews have received 10 awards for gallantry. Jim is headteacher at Aith Junior High and lifeboat operations manager at Aith lifeboat station.

There are two lifeboats serving the Shetland islands, one in Lerwick and the other at Aith. It serves the west side of Shetland’s Atlantic coastline, 21 miles north of Lerwick.

“There have certainly been some occasions when the lifeboat has been called out into quite horrendous conditions, at least Force 10 and 11,” he says. “We don’t get a lot of calls during the year - eight, 10, maybe 12 some years. But those from Aith lifeboat station tend to be long ones and cover a wide stretch of coastline. They can be a long way from the station and in some very difficult weather conditions.”

Now in his sixties, Jim’s heart still beats faster when his pager goes off: “It certainly gives you an adrenalin surge. You don’t want a call, but you get excited when there is a one.”

Alan McDiarmid, 47, teaches geography and modern studies at Millburn Academy in Inverness and has been a member of the North Kessock lifeboat crew for 15 years. He didn’t have a huge amount of sea-going experience when he joined as a volunteer but, like all volunteers, gets extensive ongoing training from the RNLI.

For Alan, being a member of the lifeboat crew is about serving the community: “I think that’s how the world works, by people putting something back, and this is my opportunity. The other thing is, it’s really quite exciting.”

The North Kessock lifeboat crew has been involved in hundreds of dramatic rescues over the years, including a few occasions when planes have ditched into the Moray Firth. People have been plucked from freezing seas seconds from death by hypothermia. In a dramatic incident last year, two local fishermen were saved as they stood on their sinking boat.

“You never expect to see a couple of guys standing on a boat that is sinking beneath them,” says Alan.

The father and son from Avoch were rescued by the lifeboat in the inner Moray Firth, but it is an image that will remain with Alan and the Kessock crew for some time.

Over the years, like all volunteer teachers, Alan has had to leave his classes when the lifeboat was called out: “There’s always a cheer as I leave, because they are glad to see me go,” he says with a laugh.

There are 824 men and women in Scotland’s lifeboat crews and last year alone they saved the lives of 886 people.

For fact sheets, lesson plans and support materials for five to 14-year-olds: www.rnli.org.ukshorethingadults.