2 June 2006

by Ivor Harris

Before taking our Hägglunds tracked vehicles onto the winter sea ice at Mawson, this week all station personnel undertook two sessions of "Hägglunds sea ice travel" training, expertly delivered by our plant inspector Craig "Alby" , senior diesel mechanic Will, and SAR leader Brett.

This included a practical session on recovery of a Hägglunds vehicle from the situation where it has broken through thin or rotten sea ice. This is a situation which has arisen in the past despite everyone's best efforts to stay on safe ice, particularly during spring as the sea ice is starting to rot and thinner patches and tide cracks may be obscured by fresh snow cover. Hägglunds are designed to float with a running engine in this situation, and in fact are amphibious to a limited degree, so it is just a matter of knowing how to recover them from the water back onto safe ice using the limited range of recovery equipment carried on the vehicle.

Hägglunds have to be recovered forwards. To simulate the trapped Hägglunds, "Alby" and Will set the vehicle up below a large blizztail snow bank below our station fuel farm tanks, with the front of the vehicle up against a deep dozer blade cut of the right depth to represent the ice edge against a floating Hägglunds.

It is then a matter of cutting 45 degree snow/ice slopes in front of the vehicle tracks, placing hinged timber ramps on the cut slopes, placing three distant snow/ice anchors using a drill and steel anchor poles, attaching "Tirfor" hand winches to steel cables from the vehicle itself and from the timber ramps to the anchors, and then extracting the vehicle up the timber ramps under its power and assisted by the hand winches pulling through the cables.

Recovering a floating Hägglunds: cutting 45 degree slopes in the ice/snow.

Hagglunds broken through ice in water with ramps nearby

Ramps
Photo: Ivor Harris

 

Place timber ramps into the cut slopes, and attach the Hägglunds and the ramps to steel winch cables.

Attach Hagg and ramps

Attach Hagg and ramps
Photo: Ivor Harris

 
 

Brett and chef Tania attach "Tirfor" winches to the cables and then to ice anchor posts.

Three Tirfor winches

Three Tirfor winches
Photo: Ivor Harris

 

Slack is taken up on the three cables to assist the vehicle while the vehicle runs up the ramps under its own power.

Expeditioners take up slack with chains

Take up slack
Photo: Ivor Harris

 

Up she comes, a successfully recovered vehicle as Bureau of Meteorology senior observer Renae works the winches.

Hagglunds pulled out of water

Up she comes
Photo: Ivor Harris

 

Mawson SAR leader Brett drives the Hägglunds while plant inspector "Alby" directs proceedings.


Expeditioner in Hagglunds

Ruffy Alby
Photo: Ivor Harris

All very straight forward.

Ah yes …..In real life of course we would be dealing with a vehicle several feet into icy cold water necessitating climbing over the roof of the vehicle in and out of the roof hatch, placing ramps down into the icy water, maybe in poor light, maybe in a blizzard….it's all fun in Antarctica!

Mawson Station Group, May 2006.

Mawson Station Group, May 2006.
Photo: Sara Conway

 

Regards from all at Mawson

This page was last modified on 2 June 2006.