Presenter Ian Gordon is about to introduce us to one of only a few sharks that make him really nervous – the Oceanic White Tip, deep in the open ocean off the Hawaiian Islands.

It’s a fast, aggressive pack hunter with a mean reputation and Ian warns that if your plane or boat goes down at sea and you survive your next problem is “the sailor’s nightmare”!

A survivor of one of the most horrible sinkings of World War II, Ed Brown, lived that nightmare with 900 others who found themselves floundering in the Pacific Ocean 12 minutes after their ship USS Indianapolis was torpedoed. Ed tells how within minutes dozens of sharks, many of them thought to be Oceanic White Tips, were circling the survivors. As soon as a survivor drifted away from the group they’d get hit. Ed was one of just 360 to survive five days of shark circling torture.

Back then there was no useful defence against attack from Oceanic White Tips. Today there is and Ian is looking forward to meeting his favourite shark, one of the most dangerous, face to face to test the effectiveness of the latest anti shark device. Invented in South Africa to try and repel sharks from beach meshed areas rather than kill them, Ian has tested the POD on white sharks and although it’s supposed to work on Oceanic White Tips they’re less predictable.

It’s a risky job and the crew and cameramen are warned to be exceptionally careful, particularly if the sharks get too excited.

Ian explains that in the event of a problem introducing another safety diver would be delivering “a lamb to the slaughter”. It’s serious stuff.

These sharks are known to attack suddenly without reason so Ian first takes to the water to test their reaction to the electric shark stick, which gives the shark a single jolt of electricity. Right on cue an 7ft (2.1 metre) Oceanic White Tip, big enough to tear him apart, swims up and gets a little too close even for a shark lover’s comfort. The jolt makes him cautious, but he’s still interested.

Ian manages to touch the shark’s tail and both he and producer/camerman Mike Bhana emerge celebrating the buzz of swimming with such a dangerous animal.

Next day Ian plans to test the POD unit on the sharks. The crew enjoy an awesome display of melon-head and Blainesville beaked whales, but no sharks to be seen.

Another day, another bucket of berley (bait) and the only killer Ian finds is an old piece of net drifting in the ocean.

A spotter plane tracks a pod of pilot whales shadowed by Oceanic White Tips and Ian prepares to join them, this time testing the POD which fires continuous shots of electric field around the diver.

However, if Ian uses his scuba gear today he’ll risk decompression sickness as his flight leaves Hawaii tonight. He has to test the POD while snorkelling. He takes the electric stick for back up. Because the POD unit is designed to sit on a scuba tank Ian can feel the electric field himself and doesn’t activate it until the shark gets extremely close. He’s definitely interested but there’s a line the animal just won’t cross.

Ian is relieved to see the technology works on this species also.

He predicts a lot more high risk divers will be using the POD in their work and eventually this technology will be used in life jackets to offer peace of mind to those like Ed, who faced the sailor’s nightmare.

Ian concludes the Oceanic White Tip is the “scariest shark” he’s ever dived with, but it’s still his favourite.