A24-69 was a PBY-5A, the amphibian version of the Catalina with retractable wheels, and the first amphibian taken on charge by the RAAF. It reached the flying-boat base at Lake Boga on 17 December 1943 and joined 11 Squadron two months later with the code FJ-A. Darwin Harbour was a major flying-boat base during the Second World War. US Navy Patrol Wing 10 PBYs were moored in the harbour when the Japanese attacked on 19 February 1942, and from 1944 the RAAF operated Catalina squadrons from the harbour on long-range minelaying and patrol missions into the Netherlands East Indies. At least three RAAF and six US Navy Catalinas were lost in the harbour, and DSAC numbers the known wrecks Catalina 1 to 6. The PBY Catalina had a 31.7 m wingspan, a 19.4 m hull and an empty weight of about 9,500 kg, so even a broken wreck covers a surprising area of seabed. On 14 December 1945, after the war had ended, A24-69 caught fire at its mooring in East Arm and sank.

The wreck lies in about 10-12 m. The forward section is intact and recognisable, including the distinctive bow turret, but the rear fuselage is missing from the navigator's compartment back. The starboard wing lies towards the rear and the port wing off the port side of the cockpit, with one engine still between the wings; its propeller was removed years ago and displayed at a Cullen Bay dive shop, and the second engine has been recovered. The aircraft was identified from artefacts recovered by recreational divers, including the contractor's plate confirming it as a PBY-5A - the only one of that variant lost in the harbour. It is the most complete and easiest of the RAAF Catalinas to dive, at a comfortable depth for Open Water divers used to low visibility, and gives a clear sense of the size of these aircraft.

Boat only. The Catalina wrecks lie in the East Arm of Darwin Harbour, south-east of the city past the port. The closest launch is the East Arm public boat ramp near the East Arm port; from Cullen Bay or the Stokes Hill / Frances Bay ramp allow about 20-30 minutes around Stokes Hill and down the harbour.

Positions are held by DSAC and the NT Heritage Branch rather than published, so dive with someone who has the mark, drop a shot clear of the wreck and time the dive for neap high-water slack. East Arm is more sheltered from the trade winds than the outer harbour but the water is often murkier.

Tide is everything in Darwin Harbour: the spring range is 7-8 m and tidal streams run hard through the harbour, so diving is generally only possible on neap tides (range under about 3-4 m), timed to the slack at high water when clearer ocean water sits over the site. Spring tides bring strong currents and silt-laden water with near-zero visibility. The dry season (May-October) gives the most consistent conditions; the south-east trade winds can chop up exposed water in the afternoon, so mornings are best.

In the wet season (November-April) run-off from the rivers and creeks drops visibility, afternoon storms build quickly, and the harbour is in cyclone season; box jellyfish are present October-May.

Descend the shot beside the wreck, start at the intact forward hull and cockpit, follow the starboard wing lying towards the rear, cross to the port wing off the cockpit side and the engine between the wings, then return to the shot. Hover - the mud stirs instantly.

No regular commercial trips; dived by Darwin Sub Aqua Club members and occasional private groups with the mark on neap-tide days.