Five hundred miles off the Pacific coast of Mexico and a long, long way from anywhere else, Clarion is one of the world’s most remote islands. We arrived on Good Friday 2009, en route from Mexico to French Polynesia.

The six Mexican marines who came out to Sentinel in their little dory were looking very uneasy as they did our paperwork. One was actually clinging to our rigging. Then we saw why - deep beneath us huge black shadows could be seen criss-crossing. We realised we had disturbed a pod of about a dozen or so Humpback whales. If any of them happened to breach close to us, the dory would certainly be overturned – Sentinel too if they were determined enough.

All day long the whales swam in the little bay around where Sentinel was anchored. We could hear them making noises like whines and groans. There was a mother and calf swimming in big circles around Sentinel, but coming closer in as they grew less wary and eventually diving right under us.

Black shadows beneath Sentinel

Towards sunset Junior became playful and started frolicking on the surface nearby, waggling his fins in the air. Then he swam head down and waved his tail at us, smacking it down on the surface of the water. A couple of the other whales, further away, smacked back. Finally he decided to practice a jump. He made a few attempts, not really clearing the water, twisting over so he landed on his back. It seemed like Mother decided she should show him how it was done. We looked awestruck as she hurtled her body clear of the sea right up into the air. She was big even by the standards of Humpbacks, nearly 20 meters long, weighing perhaps 2½ tons. There was an ear-splitting crash as she belly-flopped back into the water. Three times she did this, the third time directly towards Sentinel. We instinctively ducked even though she was a fair way off! One of the other whales also tried a jump or two, but was not as impressive.

We felt privileged to have had this experience, which apart from the lack of a few wet-suit clad pretty lady trainers, could not have been bettered by a display in a top sea-quarium.

Navigation notes.

Clarion is outermost of the scattered Revilla Gigedo group, a tiny island about 4 miles long by 2 wide, the very tip of a huge underwater volcanic cone. It is barren and uninhabited apart from a small Mexican naval garrison. There are no services of any kind. Although we were allowed to anchor for a day, the captain of the marines appeared to be looking for a particular permission among our Mexican papers, which we did not have.

Clarion anchorage from the south-west.

The anchorage is in a small bay midway along the south side of the island, in front of the garrison. We found it is situated ½ mile east of its charted position, at N18º20´.6; W114º43´.8 (WGS84). The chart shows a light on the east side of the anchorage, which actually is on the west side, and was conspicuous but unlit when we visited (see picture inset). The anchorage offers some protection from the north-east trade winds but the swell gets in and breaks heavily along the beach. The little garrison slipway, part sheltered by boulders, would be the only possible landing place. We were too intimidated by the whales to risk our dinghy.