The Esk was an iron steamer of 854 gross tons, built in 1877 at Port Glasgow as the Vampire and measuring 190.6 x 27.1 x 21.2 ft. She was wrecked on Hebe Reef on 24 April 1886. The Marine Life Network guide rates the wreck 6 out of 10: heavily broken up in about 5 m, with the boiler and stern relatively intact and the engine, winches and propeller visible.

It notes that the wreck has been heavily souvenired over many years and that yellow-green weed camouflages the remains, which are easiest to locate at low water. The barque Eden Holme lies only 40 m east, so both wrecks are usually seen on one dive. As with all Tamar entrance sites, local knowledge of the tides is worth more than any written description, and a first visit with Launceston club divers is the best introduction.

The Tamar entrance is one of the most tidally energetic dive areas in Tasmania, and the Marine Life Network guide classes several sites here as category 4-5 because of current and shipping. Hebe Reef, a shallow reef at the mouth, has claimed many ships since the early 19th century, and its wrecks are protected historic sites. The flip side of the current is prolific filter-feeding life - sponges, bryozoans and ascidians - on any structure the water flows over.

Launceston divers have access to these sites within an hour of the city, and the sheltered Low Head shore dive is a regular training and club venue. The nearest hyperbaric chamber, however, is at the Royal Hobart Hospital about 3 hours' drive south, as Launceston General Hospital has none, so plan slack-water dives conservatively.

Low Head is at the eastern side of the Tamar River mouth, 5 km north of George Town and about 55 minutes (55 km) north of Launceston via the East Tamar Highway (A8). Boats launch at the Low Head, George Town or Kelso ramps. The Tamar is a commercial port (Bell Bay), so contact Port Control on VHF and keep out of the shipping channel when ships are moving.

Hebe Reef lies at the mouth of the Tamar off Low Head, a short run from the Low Head ramp; it is exposed to northerly weather and breaks in swell. Locate wreck remains at low water, when they are easiest to find.

The Tamar heads are dominated by tide: large volumes of water flood and ebb through the entrance, and most boat sites can only be dived at slack water, typically within about an hour of the turn. North-westerly to north-easterly winds blow straight into the entrance and, against an ebb tide, create steep breaking seas over the bar and Hebe Reef. Southerly winds blow offshore and give the calmest water.

Visibility is best on the flood tide, when clear Bass Strait water enters; the ebb brings turbid river water, especially after rain. Hebe Reef breaks in northerly swell; dive at slack in calm southerly weather.

Anchor clear of the reef at slack, locate the boiler and stern, tour the engine, winches and propeller, then visit the Eden Holme 40 m east. Turn the dive at half gas (thirds where current or overhead sections are involved), deploy an SMB before surfacing for the live-boat pick-up, and complete a 3-minute safety stop at about 5 m where depth allows.

Tasmanian Divers (42 Invermay Road, Launceston) runs regular local dives at northern shore sites including the Tamar region; Launceston clubs (Tas Uni Dive Club Northern Chapter and others) dive Low Head and the Tamar heads. No charter boat is based at Low Head; boat sites are dived from private boats launched at Low Head, George Town or Kelso.