By Ginny Walton-Gould BBC News and Sport On Tour rookie reporter

The hanging cell at the docklands is still in full working order

I'm standing in a darkened cell, with a noose hanging in front of me. Below lies a trapdoor that many believe was the last thing that unfortunate French sailors saw before the lever was pulled.

The only thing that would have lit the room would have been two candles.

The atmosphere is oppressive - although the room is never used now, the thought of the harsh discipline that was meted out here is enough to send a shiver up the spine.

Not the best way you might think for the Royal Navy to promote itself as a forward-looking part of the armed forces.

But this is all part of their plan to make themselves not only more open to the public, but to secure future support for its role.

The cell itself stands in a disused part of the Royal Navy's Devonport dockyard, which is hosting one of its bi-annual navy days, where members of the public are invited to climb aboard ships, chat to sailors, and watch aerial displays.

While I was given a special peek in the hangman's cell, members of the public are not allowed - for the moment.

Historical heritage

Commander Creighton wants to preserve the history of the docklands

Cdr Creighton is the man responsible for the historical aspects of the dockyard, and it is his life mission is to preserve the navy's heritage. I met him as he finished leading the City of Plymouth Pipe Band, as the drum major.

He wants to secure funding to develop the dockyard as a place of maritime interest. That means preserving the past while looking to the future.

"It's a very spiritual thing, where we've come from, where we're going. It's more than just having a museum with a few artefacts."

As part of a trial to see if a visitor centre could be feasible, the public are being invited to view buildings normally closed off.

Unpalatable truths

Cdr Creighton hopes the public will eventually be able to wander around the dockyard's museum and feel it is part of their own heritage.

But he admits some aspects of the navy's history might be unpalatable.

"Museums are based on telling the truth, so we will have to tell the best possible truth, even if some of it is unpleasant."

One aspect that is still controversial is the issue of nuclear power. Many of the navy's subs are nuclear-powered, and a restored Valiant is open to the public at Devonport.

Sailors used to spend three months at a time living in the submarine

Walking round the sub is a sometimes chilling experience. Up to 120 men would have spent up to three months below waves, operating a regimented routine, with the only highlight of the day being what was for dessert.

The escape chute was a particularly sobering experience. If the sub was scuppered, the only chance of escape would have been to jump into a pressure suit and exit via a flooded escape hatch. Chances of survival were slim.

Nuclear power

The navy has started a trial of letting the public into the sub. Lt Cdr Martin Cropper, who runs the tour, emphasised that the main aim is to convince the public that nuclear-powered boats are safe.

With several of them in dock nearby it is an important aim.

There have been no incidents in 40 years, but some people still harbour reservations.

It was a relief to get out in the open again, where I found Michelle Reeves waiting to board the sub.

Jed Stone, an ex-submariner, welcomes the Navy's openness

She told me that in a changing world she felt reassured having seen the navy's firepower, but she felt uncomfortable with the word "nuclear".

Her partner Jed Stone, an ex-submariner on a Polaris, welcomed the new openness.

"People do get frightened when you say nuclear, so it's good for them to be reassured."

Walking around Devonport, most of the public did support the navy's continued role, though they were aware of a subtle PR exercise going on around them.

Tony Lawry, from Plymouth, was enjoying the day, but questioned the resources involved.

"The entertainment is great, but perhaps taxpayer's money could be spent on better things."

Ian Pearson, from Bromsgrove, had no reservations. "The navy is still relevant, and it knows best. I trust their judgement on nuclear power."

I do wonder how many of the families here connect the festival atmosphere to the fact that these are, essentially, machines of war.

They are getting an insight into how the navy works. And perhaps, as taxpayers of the future, they will carry on supporting the service's history, and role.