Deep diving a sea cave

Today we descended to a depth of 75 feet and eased our way into a sinuous sea cave beneath the limestone cliffs of 'Eua ... entering this place provokes a thrill that courses through the whole body and creates a galvanising sense of fully living each fraction of a second. The quiet at this depth is profound ... just the hoarse rhythm of my own breathing, and the echo of my companion's bubble stream. Above us, the roof of the cave steadily closed in, a sensation of increasing entrapment. High overhead, in a breach of the cave roof, we could see sunlight filtering down towards us.

The seabed was littered with piles of rubble from the cliffs above. Over the aeons, spurred by the frequent earthquakes on 'Eua, sections of the ceiling had tumbled into the cave, a reminder of the unstable nature of the geology in these parts.

'Eua sea cave

In the distance we could hear the singing of hump-back whales in the straits of 'Eua. My dive buddy, Tani, a stocky Tongan, was waving a torch, which lit up the black interior of the cave, and we moved steadily into its depths, hoping to find rare fish, buried treasure, perhaps a skeleton ...

The whole experience was made more surreal by the fact that it was Tani who had discovered the body of my friend Wolfgang tied to the seabed a short way up the same reef (see 'Wolfgang's Last Dive' below).

At this depth the body burns oxygen at a fair pace, and I was aware as we penetrated further into the cave of the diminishing supply in my tank. On a previous dive on this reef I had run out of air due to a faulty indicator and come to the surface too quickly - something I didn't want to repeat: Nitrogen bubbles can form in the blood and result in crippling and agonising injuries.

'Eua is on the edge of the Tongan Trench, a deep rift in the earth's crust that plunges south to Antarctica, and up which the humpback whales migrate each year: a whale super highway. 'Eua itself was thrust up by seismic activity 40 million years ago, and its elevated coral reefs are honey-combed with caves and sink holes, some of unimaginable depths.

The reefs are encrusted with a smorgasbord of corals ... candy pinks, chrome yellows ... delicate lavender blues ... like the execution of a divine sculpture garden. I have been diving these reefs for years now, and they never cease to amaze with their improbable perfection.

Just the hoarse rhythm of my breathing

As much joy, is being taken diving by a bunch of magnetic Tongans, I have grown to know and love. Finau, a stocky forty year old, whose gentle eyes belie his immense knowledge of the sea, marine diesels, diving, carpentry, engineering and ... tropical cuisine. Sam, a former commander in the Tongan navy ... a massive man, built like Jonah Lomu, who like Finau disguises his equally impressive expertise with a quiet-spoken humility.

Afterwards, devouring pizzas created in the home-made pizza oven at Ovava Tree Lodge, even allowing for the effects of post-dive euphoria, I realised this was one of my favourite spots on earth.