Sooo, I finally made probably the most advanced sewing project so far – Underquilt.
I went for quite simple design. The outer layer is slightly wider than inner and also just tiny bit longer. What that does in theory (and I think is logical) is keeping close inner layer of fabric to hammock, in the same time outer layer is kept by baffles in desired distance and as is wider that prevents squishing insulation (goose down in this case). The dimensions are based on assumption that underneath hammock the uderquilt will be “U” shaped. So below I took the picture of what I done on a paper.
Outer/inner Iayer is made of silnylon which sandwitched inside goose down. Baffles been made of untreated ripstop, which is like very fine mesh but less fiddly to work comparing with no-see-um mesh. For the edges (channels) I used grossgrain polyester ribbon 38mm. Plastic D-rings (10mm) on each corner. Suspension is made partially from bungee cord 3mm plus dyneema 2mm and two S-binners on each side.
The sewing is quite straight forward but laborious. I drawn lines on fabric (equal distance on inner fabric) sewn baffles to the inner. Then drawn lines on the other piece (spacing is not equal) and sewn baffles to outer shell. The baffles are made from ripstop as well buy untreated one (not waterproof) so the air is flowing freely. Next thing I’ve done I sew rolled hem on three edges leaving one end ready for filling.
Down filling. That’s when the fun begins (such a mess I can tell you). I found the cheapest down source as heavily reduced price down duvet (from £160 to £35). The bad side is I didn’t know filling power of the down, which is basically how many cubic inches down can fill from 1 ounce. As I didn’t know the filling power I calculated everything based on worst/best case scenario, translated it from cubic inches to metric (I’m metric person ;-)), checked, calculated again, measured and… wasn’t neither easy to weigh the down nor filling from the plastic bag which I used for weighing. So I’ve done simple thing. I watched to what level the down is filling first chamber, shook whole thing and filled rest of the chambers to the same level. I know, I know, some purists will probably moan at that point, but this way I probably saved at least an hour and a half. I probably quite overfilled the baffles, but I think that won’t be big problem, apart from overall weight and how packable it is.
Methodology of filling. Probably best option is go into (dried) bath attach the quilt by duck tape to a wall and start filling. Is easier to pickup later what fell off. I’ve done mistake doing it in living room, so you can imagine the mess ;-).
I finished the whole thing sewing grossgrain tape channels on all four edges, plus d rings in all four corners. Maybe is not lightest option but dyneema is gliding nicely inside grossgrain channels comparing with silnylon.
Suspension is very simple. Two pieces of dyneema going through two channels. The dyneema act like rails and is really easy to move whole underquilt up and down, so to lock it in place I added loops with prusik knots on each corner. Dyneema is attached to pieces of bungee cord 3mm (each side), on one side is going through cord lock, two S-binners on both sides. To tighten both ends underneath hammock I’m using 2mm bungee cord inside top/bottom channels and simply I tied knots to D-rings both sides.
Packing nicely same size as my sleeping bag, I didn’t weigh it but I guess is probably around 400g. I hung it yesterday in my garden, feel like is extremely cosy and warm.