Monday, February 14, 2011

Integral Design Sil Shelter part 2

The bug inner has a pole cup which allows it to be supported by a walking pole (like the outer). The temptation here is to place the pole in the cup for the inner and then place the inner cup into the outer cup. This is not a good idea as it limits the height the pole and provides no gap between the inner and outer at the top of the shelter. To overcome this I added a short length of string to the tie out point on the top of the bug inner’s pole cap and them simple tied this off to the pole which is placed in the outer cup.

This shows the normal peg out of the closed doors.

Doors, I had read on the net that someone had fitted a zip to the doors rather than just overlapping them, of course after much searching I could not find it again although I did find a reference which mentioned adding Velcro to the doorway. I pegged the two doors out straight and found the cut / design would not allow me to have the doors position as if zipped and not have way too much loose material as can be seen in the photo. So I abandoned the zipper idea and had a play with alternate methods of keeping the doors closed.

Here both doors are pegged out in line with the ridge. This results in the lower edge of the door being loose, and whilst there is peg loops on this lower edge they will not take up the slack.

The overlapping door is a great way to keep it simple and reduce weight, but it does make shutting the door from the inside a little hard. Of course there will be lots of times when you would want the door open at night. However with the bug inner’s front being right up against the opening and if there is a likely hood of rain the door may need to be shut. As I mention earlier the design of the door pieces does not readily allow for a zip to be fitted so after a bit of play I came up with a simple method to close the door from the comfort of the inner. By using a spare rope with line-lok and two pegs I was able to achieve a simple pulley system to pull the door closed and lock it there. This idea will clearly need a few field tests to judge if the stepping over the loose open door is practical.

I have used a spare guy line to achieve this pulley. In normal use the peg would go at the red X. But here the pegged is “fixed” to the line-lok which means the line-lok is always in the same place.

This photo gives a full view of the pulley arrangement. The red circles show the placement of the two pegs. The guy line runs around the front peg (which is hard to see in the grass) and the line-lok is “attached” to the rear peg.

Wednesday, February 2, 2011

Integral Design Sil Shelter part 1

I have had the IDsilshelter and its matching bug inner for a while. I had pitched it in the backyard a few times but when I used it in the field I was having mixed success. I felt I was not taking the same care and attention when I was pitching it in the field, so after my last trip I felt there must be a better way. Like most bushwalkers it was off to the internet. The ID web site provides a users guide for the sil-shelter but the information on pitching the bug inner together with the sil-shelter was lacking, in fact it was next to useless. So it was back to the drawing board.

I checked the measurements on the web and found them to be very similar to mine. So after working out the expected spacing between the inner and outer, I set the peg straps on the inner to 10 inches, pegged it out on the ground, at this point I checked that the distance between all 4 pegs matched the calculated values (which they did). I then placed the outer over the inner and the peg loops on the outer nicely lined up with the pegs for the inner. So far so good, but when I went to fit my walking pole (set to 44 inches) I found the inner (which I had centred in the outer) was too far forward to allow the pole to stand straight. Readjusting the peg loops on the inner to 13.5 inches front and tighten rear loops to take up the slack allowed the pole stand straight and resulted in the space between the inner and outer at the rear down from 5 inches to 1 inch. This distance at the rear was measured in a straight line, in practice it is greater as the centre rear peg out loop is pulled away from the inner rather than straight down.

Previously at the rear of the shelter I had used a second walking pole to lift the rear of the shelter externally, this time I used two different length poles internally. The wall height at the center of the back is 15inches so I selected a pole of 16.5” and 19.5” these two lengths are based I what I had laying around at home, and a desires to provide a few inches of air gap at the rear to help with air flow and therefore condensation. Whilst the photos don’t show the final pitch at the rear I was very happy with the results and will be sorting a light weight trial pole of around 19 inches for my next walk.

General view showing the clearances when pitch higher at front by extending the outer (and inner) tie down loops.

This shows the air gap provided with a 49.5 inch pole.

The peg loops provided on the both the inner and outer do not lend themselves to pitching the outer a few inches off the ground (as suggested in the users guide). This height is to allow for increased air flow, as can be seen in the photos. I added loops of 8 inches to each peg out loop. This extra length allowed me to try two different pitches, one with the same height pole (44 inches) and a second with the pole adjusted to 49.5 inches. The higher pole certainly allow for better clearance from the ground but lower pole with the pegs pushed out further provided a more protected pitch.

The yellow 8 inch extension to the peg out loops

I will cover the bug inner and door in a later post.