The SS Francis Preston Blair was an American Liberty ship of 7,196 tons (7,181 in some records) that was wrecked on the eastern edge of Saumarez Reef on 15 July 1945. The Coral Sea shipwreck register records that she was attempting to evade a Japanese submarine; Wikipedia notes that the wreck was later used as a target by the RAAF, and that an explosion hole in the starboard bow at the waterline has never been explained. Liberty ships were mass-produced cargo vessels of the Second World War, about 135 m long; her exact specifications are not given in the sources consulted.

For decades the hull stood on the reef as a landmark. The crew of the yacht Anui, who visited in 2024, report that much of the ship has now collapsed, with an extensive debris field visible while snorkelling. The wreck lies on the reef edge, so much of the wreckage is in shallow water, with the reef edge beyond.

Reef fish shelter among the plates and machinery, and the surrounding reef supports blue tangs, surgeonfish, giant clams, turtles and olive sea snakes. The shallow depth and extensive debris make it an interesting snorkel as well as a dive.

At more than 75 years old, the wreck is automatically protected under the Underwater Cultural Heritage Act 2018; nothing may be removed. Its position on the eastern (weather) edge of the reef means it is exposed to the south-east trades and swell, so it is dived only in calm conditions. Collapsed wreckage has sharp edges and may shift, and any remaining structure should not be entered. It suits experienced snorkellers and divers on self-sufficient vessels.

There is no scheduled dive operator. Access is by private expedition charter, research voyage or cruising yacht with Coral Sea experience, self-sufficient for several days and carrying compressor, oxygen and satellite communications. Saumarez Reef is about 330 km north-east of Gladstone.

Cruising yachts anchor over sand in about 10 m not far from the wreck, inside the reef, and snorkel or dive the debris field from there. Commercial tours need Parks Australia authorisation, and some islands are closed to landing.

These are remote oceanic reefs with no shelter from the south-east trades beyond their own reef rims, which blow 15–25 knots for much of April to October and make the multi-day open-ocean passage rough. Expeditions target calm windows, most often September to December; the lagoon anchorages give protection in moderate trades but the outer walls are dived only in light winds. December to April is cyclone season and trips are rarely scheduled then.

Currents on the walls and through passes can be strong; visibility is usually 30 m or more.

Snorkel or dive the debris field from the lagoon side in calm conditions, staying clear of the surf line on the reef edge and away from unstable collapsed sections. Do not enter any remaining structure.

No penetration; collapsed structure.

No regular operator – occasional private expedition charters, research voyages and cruising yachts only; any commercial tour requires Parks Australia authorisation.