Dive holes

In early summer sea ice of around 1.5m thick covers most of the bays around Casey.

To access the water we therefore need to dig entry and exit holes through the ice. We use a small commercial excavator (Avant) with a purpose built auger bit that drills a 90cm diameter hole through the ice in around 30 minutes. A system of three partially overlapping holes creates an ideal dive entry/exit point.

Specially designed auger attached to a small excavator for drilling dive hole
The specially designed auger attached to a small 'Avant' excavator
Dive drilled in sea ice
The resulting dive hole.
Photo: Glenn Johnstone

Drilling one of the holes through only half of the thickness of ice provides a step/seat for divers which greatly assists entry and exit from the water. A secondary dive hole is drilled approximately 20m away from the main hole as an emergency exit point.

Once established, dive holes remain open throughout the season (or at least until the sea ice breaks up and floats away).

Regular maintenance visits are necessary as unused dive holes may freeze overnight to a depth of several centimetres. Later in summer when the sea ice breaks out, diving is either conducted from the ice edge, from 6m inflatable boats or from the AAD's dive work boat, the Pagadroma.

A diver emerges from a dive hole to be assisted by his tender.
A diver emerges from a dive hole to be assisted by his tender.
A dive tender works to control the umbilical for the diver below.
A dive tender works from the edge of the sea ice to control the umbilical for the diver below whose bubbles can be seen rising to the surface.
Photo: Glenn Johnstone

This page was last modified on 27 June 2002.