The Sugarlump is a compact reef feature on the coast near Eaglehawk Neck made up of two large rock cubes that have split apart, leaving a fissure between them. The Marine Life Network guide rates it in 15-20 m and describes the crack as packed with life, with huge banded morwong, crayfish and anemones. The appeal of the site is the concentration of life in a small area.

The walls of the fissure are shaded from direct sunlight, so jewel anemones, sponges and other encrusting invertebrates cover the rock, while the gap provides shelter for fish. Banded morwong, which can grow very large on protected reefs, rest on the floor, and rock lobsters shelter in the cracks and undercuts at the base of the blocks. The outer faces of the blocks carry brown algae in the shallows and sponges deeper down, and butterfly perch often hang in the current on the seaward side.

It is a straightforward dive for an Advanced or experienced Open Water diver: a short, deliberate circuit rather than a long swim. Because the site is not on the regular charter roster, it is quiet, and divers who visit usually do so on private boats with local knowledge. Navigation is simple once on the bottom, since the blocks provide a clear reference, but an SMB is essential for pick-up along this cliffed coastline where there is no shore exit.

Documentation is limited and mostly historical, so treat depths as indicative and confirm current conditions with Eaglehawk Dive Centre.

Boat access only. Launch at the Pirates Bay boat ramp at Eaglehawk Neck (Old Jetty Road, off the Arthur Highway about 75 km from Hobart) or dive with Eaglehawk Dive Centre, whose boat leaves from the same jetty. The site lies along the cliffed coast between Pirates Bay and Waterfall Bay, a run of roughly 5-10 minutes; the exact mark is not published, so private boats should ask the dive centre or use a sounder to find the two blocks.

The Tasman Peninsula faces the full Southern Ocean and Tasman Sea. South-westerly to south-easterly groundswell and strong easterlies are what cancel trips: operators generally need westerly or north-westerly winds with swell under about 1.5-2 m for the open-coast sites. Prolonged southerly swell pushes surge deep into the caves and gutters and churns visibility; after a big blow allow two or three days to settle.

Late summer and autumn (February-May) bring the most settled windows and the clearest water; winter can be glassy between fronts but fronts arrive every few days. The Sugarlump sits along the east-facing cliffs, so north-easterly to south-easterly winds and swell close it; westerlies give flat water.

Descend to the base of the larger block at about 20 m, circle it, then enter the fissure between the two blocks and work slowly through it looking for morwong and crayfish. Circle the second block while rising to 12-15 m and ascend on an SMB.

No regular scheduled trips; Eaglehawk Dive Centre may visit on request or as an alternative in calm weather. Otherwise private boat/club divers.