New lease of life for Antarctic sledges

Sometimes they just don’t make them like they used to.

That’s certainly the case for three old timber sledges that have just been carefully maintained before they head back down to Scott Base for another busy season to help measure potential sea level rise.

Doug Henderson was in Christchurch carrying out essential maintenance on Antarctica New Zealand’s Nansen and Tamworth style sledges so they can continue to support science on the ice.

“I’ve really loved working on this project. These sledges are about 40-50 years old and have been used throughout their lives in Antarctica, so they were well built and have been well maintained over the years," the Arrowtown craftsman says.

“The fact they are still being used for important work in Antarctica is pretty amazing. They have stood the test of time.”

Made of predominantly ash and hickory timber, the sledges have had some New Zealand beech added during maintenance work over the years.

Doug is a bit of an Antarctic veteran – he's been down to the ice about 11 times over 30 years and has done a lot of work with the Antarctic Heritage Trust. Helping conserve Hillary's Hut in the 2016-17 season was among the projects he has worked on.

He has replaced some of the cracked sledge runners and the leather lashings which were sourced from Australia. They're preserved using special vegetable tannins for flexibility even in very cold climates.

The other rope lashings were impregnated with Stockholm tar to improve their durability, and Linseed oil was brushed on the sledges to finish the maintenance process.

This season, they will be towed behind skidoos carrying sensitive radar equipment used to measure changes in the thickness of the Ross Ice Shelf caused by melting.

The ongoing research, which is led by NIWA's Craig Stewart, will help predict the future of the ice shelf, and in turn, sea level rise.

Craig, who has used the sledges for his research for many years, says they are ideal for Antarctic work because their flexibility makes the ride smoother for equipment.

"This gives them great strength and the ability to change shape as they move over the often bumpy ice," he says.

"In addition, as the sledges are wooden with few metal components, they provide a good platform for our radar which looks downward through the sledge and through the ice shelf below."

They also play a part in the safety system, he says.

"Strong nylon ropes pass through the sledge frames and connect the skidoos, sledges and riders, providing increased security when travelling in potentially crevassed regions."

Despite now being towed by skidoos, the style of the sledges is similar to the ones used during the heroic age when they were pulled by dog teams.

The sledges will head back down to Scott Base next month and, thanks to Doug, they’ll continue important work in Antarctica for years to come.

- Read The Christchurch Star's article here.