Galah and Heron are two discarded vessels of about 20 m that were scuttled together at Fenton Patches as fish habitat under the NT artificial reef program. The NT Government list records them simply as '2 x 20 m vessels' in 25 m of water, and they lie a short distance from the Amanda Lee, so the three hulls can be visited on a single boat day.

Little has been published on the individual history of the two boats, and they are among the less-dived Fenton sites – mostly visited by anglers, with divers dropping in when conditions are good and the better-known wrecks have been done. That relative neglect is part of their appeal: fish life is often dense and relatively unpressured by divers.

Expect two steel hulls on a sand and rubble bottom, carrying the typical Beagle Gulf growth of sponges, soft corals, sea whips, hydroids and oysters. Resident fish include golden and saddletail snapper, estuary cod, black jewfish and coral trout, with trevally, queenfish and Spanish mackerel moving through. Batfish, fusiliers and baitfish hang in mid-water above the wrecks. The sand between hulls holds rays and flathead.

Because the two boats are separated by open sand, visibility dictates the dive. On a clear day both can be seen from the midpoint; in poor visibility they need to be treated as two separate dives or linked with a reel. Penetration is not recommended – interiors are small, silty and snagged with fishing tackle.

Galah and Heron suit advanced divers who have done the main Fenton wrecks and want something quieter. Plan them in combination with the Amanda Lee.

Fenton Patches lies about 17 nautical miles (roughly 31 km) north-west of Darwin in open water beyond the harbour mouth, so it is a boat-only site. Club and charter boats usually launch from the Cullen Bay ramp and marina (Marina Boulevard, Larrakeyah – ample trailer parking) or from Dinah Beach / Sadgroves Creek ramps inside the harbour, then run out past East Point and across Beagle Gulf. In a fast 6–7 m trailer boat allow roughly an hour each way in trade-wind chop; slower in a southeasterly above 15 knots.

There are no public moorings: the site is found on GPS and sounder, and a shot line or grapnel is dropped on the structure. Private boats need a competent skipper who can work the tide and keep a boat cover on the surface while divers are down.

Fenton Patches is open water in Beagle Gulf with no shelter. Dive it only on neap tides and time the dive for slack water (typically a window of 30–60 minutes around the turn; Darwin's tidal range reaches 7–8 m on springs and currents at Fenton run hard outside slack). The dry season (May–October) brings the south-east trades: mornings are usually calm, but a 15–20 knot south-easterly by late morning makes the run back uncomfortable, so plan an early start.

The build-up (October–December) brings glassy days but storms in the afternoon; the wet season (December–April) brings north-westerly monsoon winds, heavy run-off that cuts visibility, cyclone risk (November–April) and box jellyfish in the water. Visibility is best after several days of neaps and no rain.

Shot whichever hull the sounder shows most clearly, descend and identify the second vessel. Tour the first hull at 22–25 m, then navigate to the second with a compass or reel if visibility is poor. Keep plenty of gas for a return to the shot; if you cannot find it, ascend on an SMB and let the boat pick you up.

No daily operator. Darwin Sub Aqua Club (DSAC) runs member boat dives to Fenton Patches on suitable neap-tide weekends in the dry season; Dive Darwin (learntodivedarwin.com.au) and Western Blue Dive Charters offer outer-harbour/offshore wreck trips on demand when tides and weather line up. Otherwise private boat only.