Turbo is a prominent pinnacle in the lagoon of West Holmes Reef, the western of the two Holmes atolls. Marinelife.org.au gives a depth of 35 m and says the site offers a spectacular array of big pelagic fish. The name suggests what happens when the tide runs through the lagoon: the pinnacle becomes a focal point for current, food and predators.

The pinnacle rises from the lagoon floor at about 35 m toward the surface. Its sides are covered in hard and soft corals, sea fans and sponges, with the densest growth on the up-current face. The top is shallow enough for a relaxed safety stop among anthias and reef fish.

When the current is running, trevally, barracuda, mackerel and tuna gather around the pinnacle, and grey reef and whitetip sharks patrol. At slack water the pelagic action fades, and the dive becomes a more leisurely circuit of the pinnacle, with time to look at the smaller life: hawkfish on fans, nudibranchs, anemonefish and lionfish.

Turbo suits intermediate divers comfortable in current and at 25–30 m, and able to ascend in open water. Crews time it for the tide that brings the pelagics while keeping the current manageable. It is not on current operator itinerary pages, so it is dived occasionally. Coordinates are approximate, placed in the West Holmes lagoon. The site's lagoon position gives it more shelter from the trades than the outer walls, which helps when weather is marginal. Nitrox is useful for extending time near the base of the pinnacle.

Liveaboard only. Mike Ball's Spoilsport includes Holmes Reef on its 7-night Coral Sea exploratory (Cairns return), the 7-night Yongala & Coral Sea expedition (Townsville to Cairns) and the 10-night Coral Sea Odyssey; the overnight crossing from Cairns is about 240 km of open ocean. Holmes is normally allocated a day on these itineraries.

Turbo is inside the West Holmes lagoon and is dived from a mooring or anchorage nearby, timed for the tide.

Holmes Reef is a pair of isolated Coral Sea atolls about 240–250 km east of Cairns with no land for shelter. Dive the World calls it a fair-weather destination: SE trades over about 20 knots (common June–August) make the crossing and surface conditions rough, although the lagoons and western sides offer some protection. Currents are normally gentle but can be strong in the channels and on the ridges, especially on a falling tide.

September–December usually has the calmest seas and 20–40 m visibility; December–April is cyclone season.

Descend to 25–30 m on the up-current side of the pinnacle where pelagics gather, hold position close to the reef, then spiral up the pinnacle and finish on the top for the safety stop.

Coral Sea liveaboards visiting Holmes Reef – occasional.