Lining up at 7.30am in an aircraft hangar at the Royal Naval air station HMS Gannet, at Prestwick, were eight pupils from Kelvinside Academy, Glasgow, and four from Inverness Royal Academy. As they waited to be fitted with buoyancy aids and earplugs, they were eagerly looking forward to the rare opportunity to join more than 100 careers and guidance teachers for a day at sea on the Royal Navy aircraft carrier HMS Invincible.

Naval language and military precision prevailed from the start of the day as everyone was grouped into a “stick”. After safety briefing sessions, it was out to the helipad, earplugs firmly in place.

The anti-submarine Sea King was quickly over the Ayrshire coastline, the open hatch allowing maximum sea view. Ten minutes later it padded down on to the flight deck of Invincible.

As the helicopter left to collect its next “stick”, the ramp of deck beneath the group’s feet slowly sank, bringing the teachers and pupils down into the dark, petrol smelling hangar below. In this vast area, capable of holding up to 16 helicopters, the ship’s captain, R A I McLean, welcomed them as “influencers” and potential recruits aboard his “grand old lady”.

Conscious of its reputation as the “silent service”, the Royal Navy is hoping to boost recruitment at all levels with on-board visits at a number of ports around Britain. However, this was no ordinary quayside visit.

Guided around the ship, small groups moved up and down steep ladder stairways and along narrow decks to see the workings and nerve centres of the 20,000 ton carrier, one of the Royal Navy’s biggest vessels, which has a complement of more than 1,100 personnel, 10 per cent of them women. From bridge and bridge deck, past the gym and ICT-equipped education room, down into the darkness of the operations room, the ship was alive with action. The teachers and pupils talked to ratings and officers, learning about recent humanitarian operations in Sierra Leone and Mozambique and Invincible’s role in the Gulf war, protecting shipping and fulfilling the UK’s commitment to maintaining stability.

While these stories underlined the navy’s role as a “force for good”, the visitors were left in no doubt about its military capacity.

Sailing out of the Clyde, accompanied by a task group of two frigates, two mine sweepers and a replenishment vessel, Invincible entered into “hostile” waters. As a distant Caledonian MacBrayne car ferry sailed on quietly to Arran, HMS Norfolk demonstrated its gun power, firing a loud empty round from a 4.5in gun. The type 23 frigate carries 32 missiles and is capable of hitting two aircraft and two sea targets at once.

Submarine movement was then detected by radar. Three Sea Kings lifted off from Invincible’s deck, lowered sonar buoys and hovered 40ft above the sea, commencing “prosecution” of the “hostile” vessel.

Suddenly an RAF Nimrod maritime reconnaisance aircraft swept in seemingly from nowhere on the “attack”, dropping a flare as a simulated bomb. According to the commentary, relayed to the visitors over individual headphones, a “spanking new Merlin, the navy’s newest helicopter”, then swept in and dropped the final annihilating “torpedo”.

A Sea King later lifted the “spent” torpedo from the surface for use again in a mock skirmish.

In a demonstration of mid-sea embarkation - an operation necessary in peace time for cargo searches or in wartime for transfer of military personnel - a group of marines shinned down a rope from a Sea King on to a vessel alongside Invincible. This can be a challenging exercise for both pilot and marines even in a non-conflict situation. When potentially volatile cargo, such as drugs, is on board, there is often an unfriendly reception for the troops.

Sea Harrier fighter jets then roared along Invincible’s deck and took off to form an anti-air warfare demonstration with the Sea Kings. This was precision flying and put a new perspective on the capabilities of the young men and women on board the aircraft carrier.

Amid the wealth of technical detail offered in the commentary from the bridge, the teachers and pupils also appreciated some of the more personal details, such as the age of the pilots and their nicknames.

Below deck in the education room, which is a former bomb store, 30-year-old education officer Louise Thomas explained that education at all levels is available for all ranks on board the ship. Recently acquired computers, she said, will ensure that distance and software-based learning play an increasingly important role.

She teaches predominantly English and maths from GCSE to A-level, while “the expertise and talent on board ship” offers learning opportunities in most other subjects. A Royal Marines bandsman has taught music, for example, and an officer with specialist knowledge of meteorology has taught geography. “We’ve even had a chief mechanical engineer who sat GCSE English and went on to be a warrant officer,” she said.

Nineteen-year-old rating Carly McGarva thought the provision of education opportunities was a bonus. She left Annan Academy half-way through her Higher year, so she might make use of the classes to top up her qualifications.

Wren Operations Mechanic (Above Water) Sandra Wanless, 18, clearly enjoys life at sea. She left Trinity Academy in Edinburgh at the age of 16 with eight Standard grades. “I always wanted to join up,” she said, “and put my name down for the navy in first year.” Her main interest lies in gunnery and radar seamanship, focusing on above water warfare, and she enthusiastically described four-hour watch-keeping duties in the operations room.

Two of the pupils from Inverness Royal Academy, Kevin Docherty and Graeme Mackay, were amazed by the diversity of jobs on board the carrier. Although they were members of the school’s Young Engineer’s Club, and the day at sea was part of a prize for winning the Royal Navy Young Engineers Challenge, the two S6 boys had not particularly considered a career in the Royal Navy. Kevin aims to study physics at Glasgow and Graeme is going to study electronics at Edinburgh, but they now realise that the navy could provide career options for them after university.

The Kelvinside Academy pupils, who were shown around the ship by a former pupil of Glasgow Academy, also were surprised at the diversity of jobs in the navy and the ways in which different school subjects could be exploited, said teacher Alison Smith, who accompanied them. Mhairi Rushforth, Kelvinside’s first female naval cadet, was doing Higher French, for example, which could allow her to play an important diplomatic role. S3 pupil Cameron Smith suggested that it could be useful in the troubled areas of French-speaking Africa.

Although the visit was not exclusive to pupils who were cadets, those who were had not felt they were necessarily moving towards a career in the armed services. However, Douglas Naismith (S5), who hopes to study computer science, said he would now consider applying for Royal Navy sponsorship. Roddy Mair in S3, who would like to do a degree in engineering, is thinking the same. And S3 pupil Scott McAnna, who was sceptical about a career in the services before the visit, went home giving the navy serious consideration.

Reacting to the potential challenge of being actively involved in warfare, Mhairi said: “You just realise that’s what you’re taking on when you sign up. When we went to the operations room, even though the situation was a mock-up, there was real tension.”

The pupils were impressed by what they had seen and learnt. Douglas Naismith concluded: “It’s not every day you get the chance to go on a helicopter out to an aircraft carrier. The ship had a great atmosphere.”

For information of Royal Navy careers and recruitment, contact the recruitment officer at HMS Caledonian in Fife, Lt-Com Heather Nicholson, tel 01383 412121www.royal-navy.mod.uk