Shelter for Foul Weather, High Winds, and Long Term Use

I have not spent any time in Patagonia… so these comments are based on general principles and what I have heard about Patagonia from friends.

Given the extended nature of your trip, I would be inclined to go with a pyramid tarp because it would be light weight, stand up to harsh conditions, easy to pitch, and provide a great deal of room which I think would be valuable after six months with someone. I think more "round" tipi / hex tarps might stand up to the weather slightly better, but I don't think that minor advantage offsets the added complexity of getting a good pitch.

If I didn't feel like I needed the extra room of the full pyramid, I would consider one of the dual peak shelters, or the oware alphamid.

I love the ID Mk1 / Bibler i-Tent… as a solo winter tent, or for short trips with someone I am friendly with. But I won't want to spend 6 months in one with someone else.

I would be inclined to pass on the sil-dome because I would be concerned about it standing up to high winds. Anyone have experiences they want to share?

The Nallo is a nice shelter… but it doesn't compare to the others when it comes to weight / protection. I would also consider other tunnels like warmlite.

I am planning a similar trip and have considered the Hilleberg Allak. More weight, but i am attracted to the dual vestibules and versatility. I will be traveling in the central Andes of Peru and Bolivia where extreme winds and rain will not be as much of a factor, but I think the Allak would also be capable of withstanding southern Patagonia where I will be for the later half of my travels.

Another possibility – the Stevensen Warmlight series of tents. They are lightweight, roomy, expensive, and capable of taking high wind loads. From their website: "High Wind SECURITY: Designed for smooth airflow in high wind, WARMLITE tents resist 95 mph winds or, with optional inside WIND STABILIZERS up to 160 mph"

warmlite.com

I did a trip to Patagonia two years ago through the Fitzroy area and the circuit in Torres Del Paine in Feb-Mar. I took along the Sierra Designs Hercules Light AST because I got it cheap on ebay. This tent weighs about 6 pounds and is a double wall mountaineering tent. There were a lot of developed camps you could get away with a tarptent or tarp but I definitely put the wind resistance of my tent to the test in a few exposed places as well as the bathtup floor. What areas and types of terrain are you planning on travelling through? I have no experience with pyramid shelters but would have some concerns about site selection and drainage in heavy rain. It depends on if you want to keep hiking to find a good place to pitch a pyramid. What weight will you have to carry in the way of a bivy, groundsheet, and/or synthetic bag to keep you dry if you are ready to crash but water may pool up where you finally decide to pitch your shelter. Do you want to deal with that for possibly several days in a row? I think I would lean towards a single wall tent you can pitch from the inside like a bibler or similar design. I admit I may be a bit traditional but the weight penalty may be worth the flexibility of throwing down in a non ideal spot. On the other hand the Arctic 1000 trip and the Journey on the Wild Coast have been done with pyramids.