Underquilt ends not cold?

[Joz]

I'm going to attempt making my own underquilt for my BMBH. I've been looking around the JRB pages and this forum trying to get a feel for how I want it done.

What I don't get is, unless you have a gathered end hammock, and your quilt doesn't cover the ends of the hammock, doesn't that create a cold spot? Or at least lets the wind in, even if you don't actually have any body contact with the ends?

So is it sufficient to make the quilt to cover the long sides only, and not worry too much about the ends of the hammock? Or do I try to make a bath tub type model?

[Dutch]

A bridge is very conducive to making an UQ. For some reason it doesn't have to be as wide and all you need is differential baffles one direction. Also there doesn't seem to be as much of a problem with air getting in the ends,

[Joz]

all you need is differential baffles one direction.

Yeah, I don't understand what you just said.

Is this the way you have the seams, or something?

[vitamaltz]

I see what you're saying. The head and foot ends of the hammock usually aren't insulated with down, even if the entire bottom is. You might make end caps, u-shaped pieces of fabric to fit the ends of the bridge. That helps to block the cold wind and closes you off a little better the way a gathered-end hammock does. The underquilt is important because the insulation under you gets compressed and cold air circulating below chills you. Since you aren't squishing the ends, the foot area of your sleeping bag or quilt should keep your feet warm and something covering your head will keep that part of you warm.

[warbonnetguy]

the quilt mainly just needs to be anywhere where your backside is in contact with the hammock. your topside insulation takes care of the rest (ie sleeping bag). you shouldn't need to worry much about the areas that are past your body. your tarp and the hammock fabric itself will block plenty wind. in extreme conditions you might consider a hammock sock to stop any cold drafts and raise internal temps a few degrees.

[Joz]

Allright, cool, thanks.

[GrizzlyAdams]

Yeah, I don't understand what you just said.

Is this the way you have the seams, or something?

I understood him.

On a bridge hammock the person lays in a straight line; unlike a gathered end hammock, in a straight line you can still lay flat. So the differential cut---what keeps the outside shell of the quilt hanging away from the inside, needs only to be figured out in the cross-wise direction.

Said differently, when I make a differentially cut UQ for a bridge, my baffles run head-to-foot, are straight, and have no darts to make them curve. I'm not skilled enough to make a full-length differentially cut UQ for a gathered-end hammock, but it looks as though the "laying on diagonal" thing introduces another dimension to consider when shaping the inner and outer shell.

Grizz

[Walking Bear]

When I made my UQ for the bridge I made a curved form that was about as round as I am. That's a big round circle. The form was made of wood strips that ran the length of the form. I used batt insulation. I placed the inside fabric on the form, then the insulation, and then the bottom fabric. My loft was about two and a half inches. Then I quilted the layers with string. Then pinned the ends and sides. Then to the sewing machine to finish.
I used crossgrain on both sides of the UQ with loops on the corners. I attached to loops on the hammock with short shockcord loops to keep it tight.

[Peter_pan]

Whether a hammock is gathered end or bridge style.... The ends need not be insulated as they are un occuppied.... That is the primary benefit of under quilts over full coverage items like the Pea Pod, reduced weight, reduced stuff size, and reduced cost. Observe the uncovered ends of an 8-8.5 foot hammock (actually a curvered bottom with a functional material length of 9.0-9.5 or more depending on its cut length and gathering technique) with a 6-6.5 foot UQ properly attached.

The end cap of JRB BMBH and home made bridge hammocks stands out as un insulated because of the inherent flatness, ie no gathered end curve to a point above the occupant...UQ on GEH apprear to curve up behind an occupant because the hammocks in fact do curve up themselve...Even on the asym gathered end hammocks there is still a curve, thus the UQ takes up that curve.

A keep point to remember is that no hammockor, tarp, or open tent for that matter, sholud be pitched with its opening end into the prevailing wind. Site selection is still fundamental to all shelter systems, especially hammock & tarps.

Pan