Brothers & Daedalus

Everything here happens from a liveaboard on a fixed week-long loop. The boat crosses overnight from the mainland, picks up a mooring or lies off the reef, and runs its dives from the back deck or by zodiac, with divers dropped upcurrent and collected in open water at the end. Anchoring is not permitted on these reefs, so surface intervals are spent on a mooring line or under way, and the schedule bends around wind: an itinerary is written as an intention rather than a promise, and a blown-out day can mean a night's steam elsewhere.

The reefs are simple shapes with complicated water around them. Big Brother is a long rock carrying a manned lighthouse, Little Brother is smaller and lower, and Daedalus stands alone further offshore. Each is a hard top ringed by wall, so a dive is usually a traverse along one face with the current on your shoulder, finishing with a hang in the blue. Big Brother's northern point and the northern plateau at Daedalus are where the water accelerates and the fish stack up, while the leeward sides get used when the exposed corners are unworkable. Little Brother's walls carry dense soft coral and large gorgonians.

The two wrecks are dived as wall dives. Both lie down a steep slope rather than on flat seabed and both run well past recreational depth, so divers work the plating from the shallow end, the Numidia's bow within easy reach and the Aida deeper again, and turn before depth becomes the problem. How much of either ship you see is decided by the current that morning. Sharks tend to show away from the rock, in mid-water on the crossing or circling the boat during the safety stop, which is why guides insist on tight groups and a controlled ascent on a line.

This is a trip for experienced divers comfortable with being small in open water. Groups are self-reliant, entries and exits happen in moving water, and there is no house reef to sit a dive out on. Operators generally set a minimum logged-dive count, often around fifty, and expect a surface marker buoy and an audible signalling device on every diver; permits for the offshore marine parks are arranged by the boat before departure. Divers who want gentle reef, wide site choice and a bad-weather alternative should stay on the coast.