Critique please
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Mark Fowler
(KramRelwof) - MLife

Locale: Namadgi
Critique please on 06/21/2012 07:01:08 MDT Print View

There are a couple of issues I am wrestling with regarding a two person shelter for reasonably exposed 3 season conditions and seek your thoughts. While much of my walking is solo, my partner does come along on some weekend trips where we use a REI Quarterdome. I am planning to take her on a 6 day walk in Tasmania this summer and hopefully other longer trips in the future so I want to cut a kilogram from the shelter to help compensate for having to carry most of food for both of us plus the shelter.

I continue to play with shelter ideas and after using a MLD Duo Grace tarp in cuben and a SMD Gatewood Cape with a Serenity net inner on several month long trips I decided I really prefer an enclosed shelter but I also felt that it needed to have a short ridge to improve roominess rather than rise to a peak like the Gatewood Cape. I have played with designs for several years and keep coming back to the basic shape of the SMD Haven or Suluk46 (Steve Evans) ALL-WET design (apologies to other manufacturers who may produce something similar).

The beauty of this shape is that the centre section for a 1 person shelter is about 600mm wide and 1200mm for a two person version. In 0.74 cuben this equates to a weight increase of about 75g in sizing up from a 1 person to a 2 person shelter. The SMD Haven comes in at 295g (10 oz) for two person and offers 2 entrances and plenty of room.

The same applies to an mesh inner (assume 1oz cuben floor with mesh or 8d canopy and mesh vertical sides/doors which I think I can build at a weight of 320-350g) which would reduce in weight by about 85g for a 1 person version. So this gives a weight increase of 160g for carrying a 2 person vs a 1 person shelter.

How do you see this? Would you just carry the 2 person even on solo trips or consider a 1 person inner to fit the 2 person tarp, or have a 1 person and a two person shelter?

My second dilemma is the construction of the roof section of the inner similar to the Haven net inner. I like the idea of using something like 8D/M50 for the roof and possibly the lower sections of the doors to minimise drafts and reduce condensation getting into the inner due to the DWR finish. There appears to be no weight penalty, if anything 8D appears slightly lighter than nanoseeum mesh but I don't read of anybody trying this. So are there issues I have not considered - either the fabric choice or other issue?

Over to you!

Daryl Daryl
(lyrad1) - MLife

Locale: Pacific Northwest, USA, Earth
Re: Critique please on 06/21/2012 09:17:52 MDT Print View

Mark,

I too like the design you mentioned. I first saw a tent with this design in a sporting goods store in Vancouver BC in the early 1970s and have been making and buying tents with this design ever since.

I'd suggest making a two person first. I think you can get it down to the 2-3 lb range(tent, fly and poles) easily using the lightweight materials you are proposing. You can use it for 2 person or solo trips and then consider the 1 person options.

I'd give the Tarptent Scarp 2 a good look and then modify as you see fit from there. Using the Scarp 2 as a reference I would make one for my use that was smaller, had no carbon fiber struts on the ends, had lower ends, did not have end walls on the fly, did not have straps for winter pole use and had a cuben fly.

The Suluk 46 tent has two poles. My experience is that adding a cross piece is well worth the small extra weight. Steve at Suluk 46 was also considering the addition of a cross piece. I think the Scarp's hooped pole is the best option, however. Pole is easy to make and easy to replace and interferes less with entering and exiting the tent than a straight poles.

Best of luck.

Daryl

James Berwick
(jhb0510) - F
8d innertent on 06/21/2012 09:18:30 MDT Print View

I am thinking of doing something similar and having had a goilite inner with noseeum had decided on using 8d.

Paul Johnson
(johncooper) - F

Locale: SoCal
Haven Tent Design on 06/21/2012 17:04:06 MDT Print View

I like the Haven style design as well. See this link on a MYOG design that I developed. I am still in design.

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=62531&skip_to_post=534689#534689

Regarding width: my calculations are that a foot of width adds 1oz (ie 12 square feet) on the fly using .75oz cuben, so I fully agree with going wider.

Regarding the inner net. The haven inner is 14oz, compared to only 10oz for the fly. The inner also reduces headroom and floor space. My recommendation is to go with perimeter netting and raise the fly six inches to minimize condensation. Attach polycryo to the netting for a ground sheet. This solution cuts the inner weight in half and solves your dilemma of having one person and two person inner nets. Finally, this eliminates the second zipper and entry point, making it easier to get in and out of the tent.

Here is a link to a similar thread from Daryl Clark. He has implemented what you are considering. Non coated inner net material seems to work well.

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=42163&disable_pagination=1

I am curious whether you are considering a cross bar. If not, how do you plan to secure the trekking poles?

Edit: more direct response to op

Edited by johncooper on 06/21/2012 17:26:43 MDT.

Mark Fowler
(KramRelwof) - MLife

Locale: Namadgi
Thanks for the feedback on 06/22/2012 19:18:14 MDT Print View

Thanks all for the feedback. I think I will buy a cuben Haven fly and build my own inner for it. I looked at building my own fly with a cost saving of around $150 but being time poor I think I will spend the dollars rather than the hours.

I am unsure how the poles are anchored at the top of the Haven but it should possible to add in a cross piece. I use Ti Goat poles and have worked out a simple way to connect them - it is just a matter of how this will fit into the peak of the Haven.

I will build my own 2 person inner using 1oz cuben for the floor, 8D for the roof and nanseeum for the doors but may make the bottom 30cm of the doors in 8D to minimise drafts and splash. This should weight 300g plus attachment elastic/cord etc. giving an all up weight of under 700g, This is comparable on a per person basis to a Hexamid and net inner combo, a combination I have been considering for solo use.