The channel between Orpheus and Pelorus islands carries tidal water through the Palm group, and the reefs along it are some of the most fish-rich in the region. The North Queensland Underwater Explorers Club documents two main sites. The Western Edge runs from the house point along the southern face of Pelorus Island on the western edge of the channel.

Depths rarely exceed 14 m, and the reef is characterised by large brain corals undercut to form swim-throughs, together with sea fans. In winter visibility reaches 15 m, and divers often hear humpback whale song in the background. The Pelorus side of the channel is zoned Habitat Protection; the Orpheus side is Marine National Park.

Ray's Lump is the club's gem. It is a pair of small coral outcrops, each roughly the size of a tennis court, rising from a sandy bottom at about 16 m in the middle of the channel. The club compares them to the small reefs near Madang in Papua New Guinea: miniature reefs packed with life, with clouds of fusiliers, coral trout, sweetlips, cod and resident blacktip reef sharks.

Because the outcrops stand alone in a current-swept channel, fish concentrate on them, and a single dive can circle both. The club deliberately withholds the location, so divers need local marks. A third, related site, the Danger Marks on the Orpheus side, offers shallow gutters.

Channel diving demands attention to the tide: currents run hard on springs, and slack water on neaps gives the best conditions. With a boat attendant and good planning, these are among the best dives in the inshore central Great Barrier Reef.

Boat only. The Palm Island group lies 20–25 km off the coast between Townsville and Ingham. The quickest access is from the Lucinda or Dungeness boat ramps near Ingham (about 1 hour 20 minutes' drive north of Townsville via the Bruce Highway), from which a small boat reaches Orpheus and Pelorus in about 30–45 minutes across Halifax Bay; Taylors Beach ramp is an alternative.

From Townsville the run is roughly 1.5–2 hours. Orpheus Island Lodge guests arrive by helicopter or seaplane and dive from the lodge's boats. Campers on Orpheus (QPWS permit) and Pelorus (self-sufficient, Hinchinbrook Shire Council) usually arrive by private boat or water taxi.

Use public moorings where available and check no-anchoring areas. The Western Edge is dived off the house point along Pelorus's southern face; Ray's Lump sits mid-channel in about 16 m and its exact position is deliberately not published by NQUEC – obtain marks locally and drop a shot on the sand beside it.

The Palms are high continental islands, so some shore always offers a lee, but the Orpheus–Pelorus channel and exposed points are hit by the south-east trades (15–25 knots, April–September) and by strong tidal streams – springs can produce currents that make the points undiveable except at slack water. Visibility is typically 6–10 m and reaches 15 m in the winter channel; it falls after strong winds and during the wet season (January–April) when the Herbert River floods discolour the water. The calmest, clearest conditions come in the October–December build-up.

Marine stinger season (box jellyfish and Irukandji) runs roughly November to May – wear a full-length stinger suit or wetsuit with hood and gloves, carry vinegar. Cyclone season November–April; tropical lows and cyclones can close sites and damage coral (TC Yasi 2011, TC Debbie 2017). The channel concentrates tidal flow; dive at slack water on neap tides.

Winter visibility reaches 15 m.

Western Edge: drift or swim along the edge at 8–14 m among the brain corals and swim-throughs. Ray's Lump: descend the shot to the sand at 16 m and circle both outcrops (each about tennis-court size), rising up their sides; ascend on the shot.

Orpheus Island Lodge – private dive charters for guests to local reefs (minutes away) and the outer reef (~75 min), plus Discover Scuba shore dives; otherwise private boats from Lucinda/Taylors Beach, campers and NQUEC club trips. No scheduled public dive trips.