As dozens of daredevils prepare to bungee jump off the Cleddau Bridge in Pembrokeshire this August, the organisers have teamed up with bungee experts to learn more about what they can expect.

When the jumpers take that leap of faith, they will be plunging 150-feet, roughly the height of a 16-storey building, with only a large bonded rubber band strapped to their ankles.

But that is nothing compared to the speed - they can expect to average 50mph as they go into freefall.

For the last two years, students from the University of Wales Trinity St. David’s extreme sports engineering department have been involved in the event to understand more about aspects such as the acceleration jumpers experience and forces through the bungee rope.

The department has now produced an app for jumpers and spectators - https://play.google.com/store/apps/details?id=com.chaostrend.bungeeapp&hl=en_GB

As participants count down to their jump, nerves will no doubt kick in, but what other feelings will they experience? Pembroke Dock businessman James Parfitt, who is a member of the organising team and took part in the 2016 jump, neatly sums it up: “An adrenaline rush and a heart pumping insanely.’’

Fear is understandable, but what other thoughts occupy people’s minds when they are standing on the bungee platform?

“Will I survive? Can I trust that bungee rope with my life? Will I hit the water? All these things rush through your head,” says James.

Although a stiff drink might seem a reasonable antidote for nerves, alcohol consumption should be strictly off limits.

“Don’t drink or overeat before you jump and make sure you are fit enough to jump,” the organisers advise. “And keep yourself as calm as possible.’’

Jumpers will register at Hobbs Point before they are taken to the jump site, where they are again briefed and the appropriate safety checks made.

“Then it is ‘one, two, three, bungee’!” says James.

Once the jumper has stopped bouncing, they will be lowered onto a high-speed rib and returned to Hobbs Point. 

The event, organised by the Pembroke Dock Town Team, takes place on August 19 and 20 and there are still some places available.

“It is the only chance to bungee off the bridge in Wales and only one of three opportunities do to so in the whole of the UK,” says Dilys Burrell, another member of the organising team.

To book a place, visit www.bungeeoffthebridge.wales.