Chris Gardner at Omaru Falls
New Zealand Outdoor Instructors’ Association bush leader and senior writer Chris Gardner, pictured, continues his On The Trail series by discussing shelter and sleeping bags.
Chris Gardner enjoys a hot coffee on a cold winter’s day.
Be prepared to overnight every time you go for a hike or a tramp.
Weather is unpredictable. Rivers rise. Slips could block your path. A trip could leave you with an injury and unable to walk.
Always take a survival bag. A plastic pack liner, keeping rain and the river out of your gear, can double as a survival bag. Crawl into a water and wind resistant aluminium-coated emergency bag to become insulated from the elements and prevent hypothermia.
A survival bag can be cut open to make the roof of an emergency shelter or make an emergency shelter from fallen branches. Dry ferns and leaves make springy beds and piled 30 cm high are good insulation.
Practice making an emergency shelter in the hope you may never need to build one under pressure in a real-life emergency situation. It could save lives.
Take a tent or emergency shelter on a multi-day tramp, even if you plan to stay in a Department of Conservation hut.
Great, lightweight, tramping tents are expensive, but worth the investment if you plan to use them regularly. You won’t get change from $1000 if you want a one-person tent weighing less than one kilogram. Add another $500 for a two-person tent. Cheaper and heavier tents are available from mainstream outdoor retailers.
Lighten your load by splitting a multi person tent between those who will sleep in it. The disadvantage is if one of those people becomes lost on the trail, they will not have a full tent, and neither will those they become separated from.
Great, lightweight, tramping tents are expensive, but they will protect you from the elements. Photo: Chris Gardner
Shelter is only half the equation – staying warm through the night requires the right sleeping system.
Sleeping bags have comfort, lower limit, and extreme ratings. The comfort rating is the temperature a standard woman can sleep comfortably in, the lower limit is the temperature at which a standard man can sleep without waking, and the extreme rating indicates the temperature where hypothermia is unlikely for a few hours.
Down sleeping bags are the tramper’s choice, compressing well into a backpack. Never put anything on top of a down bag you are sleeping in, as it reduces the down loft and the insulation. A wet down bag will lose its insulation too.
Synthetic sleeping bags, usually filled with polyester, are cheaper than down filled bags. But they are a lot bulkier too. They are still warm when wet.
A good compromise is a hybrid sleeping bag filled with a mixture of down and synthetic material.
I have one of each I use for different scenarios. I default to a bag rated for subzero temperatures and sleeping in it opened out when I am too warm.
I always take a sleeping bag liner to add another layer of warmth and protect my sleeping bag from my trail weary body. A merino wool liner is great in winter, and cotton silk blend in other seasons.
A good sleeping mat, also rated for your conditions, is essential. Without this you’ll freeze in the best sleeping bag and liner.
Closed cell foam mats are bombproof, but they are bulky.
Inflatable mats are popular. But, as I found out in subzero temperatures last year, they can leak, and you can wake up shivering on the ground. Reinflating a mat in a cramped tramping tent at 3am when it is -3 degrees is not fun.
A survival bag, emergency shelter, tent and reliable sleeping system could mean the difference between danger and discomfort. 
