Marchart 3

Meet the site

Marchart 3 is the vessel that started Fenton Patches. The 32 m, 244-tonne steel ship began life as a research vessel, was later converted into a prawn trawler and ended her working life as an oil-rig tender before being scuttled in 1988 as the first major structure in the NT Government's artificial reef program at Fenton Patches. She was powered by twin Caterpillar diesels and was built to cruise at about 11.5 knots, which gives some idea of her solid, workboat build. More than three decades on the sea floor have turned her into one of the most productive fish-holding structures off Darwin.

The wreck sits upright on a flat sand and rubble bottom in about 25–28 m, with the superstructure rising to within about 18 m of the surface. The hull is intact enough to be read as a ship: a raked bow, open forward holds, the deck house and wheelhouse aft, and a deep counter stern with the rudder still in place. The holds and cabin can be looked into with a good torch, but they carry a heavy layer of fine silt and are not places to go without wreck training; the rewarding part of the dive is outside the hull. The area around the rudder and under the stern is consistently the best for fish – golden snapper and saddletail snapper stack up in the shade, black jewfish hang in the undercut, and big estuary cod and Queensland groper take up residence in the holds.

Growth on the hull is typical of turbid Top End water: sponges, soft corals, small gorgonians, hydroids and oysters rather than hard coral, with trevally and mackerel sweeping past the mast area. Because the wreck is compact, one dive around it at slack water is usually enough to see everything, and most boats pair it with the Amanda Lee, the Antares group or Bus Stop Reef nearby.

Visibility is the variable that makes or breaks Marchart 3. On a good dry-season neap it can reach 10–15 m and the whole silhouette of the ship is visible from the shot line; after wind or spring tides it can drop to a few metres. It suits advanced divers comfortable with a descent on a line in open water, limited no-decompression time and a short tidal window. For Darwin divers it is a benchmark dive and the reference point for the rest of the Fenton reef field.

What you might see

Golden snapper, saddletail snapper, black jewfish, estuary cod, Queensland groper, coral trout, trevally, Spanish mackerel, batfish, cobia, sweetlips, sponges, soft corals, hydroids

Location

The original centrepiece of the Fenton Patches artificial reef field, about 17 nm north-west of Darwin (12°10.275'S 130°40.635'E).

Facilities nearby

Departure facilities at Cullen Bay Marina (fuel, ramp, toilets, cafes) and Dinah Beach; air fills in Darwin only.