The steamer Kawatiri was hit by a large wave while entering Hells Gates in August 1907, flung against the breakwater and deposited on the North Spit, since renamed Kawatiri Shoal. The Marine Life Network guide recounts the tragedy that followed: a lifeboat capsized and five people drowned - a stewardess, a woman and children including the Assistant Keeper's family - before the remaining crew were rescued once the wind eased; the wreck stayed intact for three months before breaking up.

The wreck lies buried in shifting sands in 2-4 m, and sand movement periodically uncovers starboard hull plating and machinery. The guide rates it 6.5 out of 10 but category 4-5 in difficulty: worth a look and a photograph only on an exceptionally calm day, with a serious risk from freak waves, and it suggests using a self-draining boat.

Tasmania's west coast faces the full Southern Ocean, and the Marine Life Network guide notes that most of it is diveable only after easterly winds have flattened the swell - an uncommon event largely confined to summer. Macquarie Harbour and Cape Sorell provide the only reliable shelter from south-westerly swell. Crayfish grow large here, abalone are common and fish life is thin on exposed reefs, which are battered by constant swell.

There is no dive shop, air station or chamber anywhere on the west coast; the nearest hyperbaric chamber is the Royal Hobart Hospital, about 4 hours from Strahan by road. Every west coast dive should be treated as remote: carry oxygen, a radio and an EPIRB, and have a realistic evacuation plan.

Strahan is on Macquarie Harbour, about 4 hours from Hobart via Queenstown or 3 hours from Devonport/Burnie via the Murchison Highway. Boats launch at the Strahan ramp and run about 30 km (45-60 minutes) down the harbour to Hells Gates, the narrow, tide-swept entrance at the harbour mouth. The entrance is notoriously dangerous: strong tidal streams, a shallow bar and freak waves.

Cross or dive it only in calm conditions, near slack water, with a seaworthy, preferably self-draining boat, and check MAST advice. The Kawatiri lies on the North Spit inside the entrance; approach only in exceptional calm.

Hells Gates faces the open Southern Ocean to the west; any westerly or south-westerly swell produces breaking waves across the bar and entrance. Tidal streams run hard through the 120 m-wide gap and outflowing tannin-stained harbour water reduces visibility, especially after rain and on the ebb. Only dive in rare easterly weather with minimal swell, at slack water.

In exceptional calm at slack water, snorkel or dive over the shoal to view exposed hull plating and machinery; have the boat stand off ready for pick-up. 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.

No dive operator on the west coast. Air and gear must come from Launceston, Burnie/Devonport or Hobart (the regional guide notes locals sent tanks overnight to Burnie for fills). Sites are dived only by self-sufficient private boats and abalone divers.