With the sea ice around Davis now in good condition to travel upon safely with Hägglunds vehicles, it was time to make sure everyone was able to operate as part of an effective team and recover the Hägg in the event of a ‘break-through’ in the ice. While the ice is of ample thickness to take the weight of the Hägglunds (it has to be over 600mm and we have been measuring in excess of 750mm in most places, it will likely double that thickness too with any luck), there is still the possibility that you can go through the ice. For example, at a snow hidden tide crack or ‘lead', a crack that forms between islands or a shallow section etc. There is also the possibility that the ice may break out due to high winds or an uncommonly high tide, which is why we check the tides as well as weather when planning a trip.
A basic Hägglunds recovery will be dependent, of course, on the situation at hand but will usually involve having to turn the Hägglunds 180° so that you can recover it forwards, over the ice you have already covered.
The design of the tracks make forward recovery orders of magnitude easier than a rearwards recovery. This will entail using a chainsaw to cut out sections of the ice and turning the Hägg around. Thankfully, the Hägglunds float well and are considered an amphibious vehicle. At our training at the Australian Antarctic Division in Kingston, before departing for the icy continent, we actually drove one around in a dam for an extended period of time!
Once you have the Hägg turned around, you can use ramps anchored to Tirfor winches (so you can move them along with the Hägg) and then winch it out of the water while also driving it up the ramps and winching the ramps forward at the same time. This sounds fairly simple and it is, but it takes a lot of time to do safely, you have to make sure everything is right before beginning a recovery. The first rule is don’t panic!
Here are some shots of the two different teams we took through the recovery training on the day, thankfully, it was only −20°C!