Mt Washington 3 20° Three-Season Hammock Underquilt

The Mt Washington 3 is JRB's 20°F three-season hammock underquilt — built for hammock campers who want reliable bottom insulation without the pad-wrestling and cold-spot problems that come with sleeping bags used underneath. 850FP down, dual differential cut, JRB Suspension System included.

Built for Hammock Campers Who Want to Sleep Warm from Below, Not Just on Top

Sleeping in a hammock introduces a problem ground campers never face: every bit of insulation beneath your body gets compressed flat by your weight, losing its loft and nearly all of its insulating value. A sleeping bag used underneath is simply not doing what it was designed to do. An underquilt solves this by hanging freely below the hammock fabric — it never touches your body, never gets compressed, and the down stays fully lofted all night. Without an underquilt, no amount of insulation on top of you will keep you warm below 50°F in a hammock. The Mt Washington 3 is the solution for three-season temperatures down to 20°F.

How It's Built: Dual Differential Cut, 850 Fill Power Down, 1.1 oz Taffeta Shell

The Mt Washington 3 uses Dual Differential Contoured Radial Baffles — the construction that separates a purpose-built underquilt from a top quilt repurposed underneath. The inner shell is cut smaller than the outer shell so the quilt conforms naturally to the curved underside of a hanging hammock without pulling the two shells together at the edges. A flat-cut quilt would compress the down exactly where it matters most as it curves around the hammock. The differential cut keeps every baffle full and lofted regardless of how the quilt hangs. This is why a differential-cut underquilt performs at its rated temperature when a repurposed top quilt used underneath would leave you cold.

The Mt Washington 3 is filled with 850 Fill Power RDS-certified down. Fill power measures how many cubic inches of loft one ounce of down produces when fully expanded — at 850FP, the Mt Washington 3 achieves its 20°F rating with less fill by weight than underquilts built with lower-grade down. Every Mt Washington 3 ships with a 33% overstuff by weight, so it holds its rating even as the down accumulates oils and dirt between cleanings and loses loft.

Suspension is via adjustable shock-cord loops at each end. Cinch the ends to seal the quilt tight against the hammock on cold nights; loosen slightly to vent on warmer nights. Setup takes under a minute and works on all gathered-end and bridge hammocks — ENO, Hennessy, Warbonnet, Dutchware Chameleon, and most other brands and DIY builds. The suspension system is included.

The shell is 1.1 oz taffeta with a DWR coating. Every Mt Washington 3 ships in a storage bag that does not compress the down — keep the quilt in it between trips for long-term loft preservation.

Named for the Trail

Mount Washington, at 6,288 feet, is the highest peak in the northeastern United States. The summit weather observatory has tracked temperature swings, icing, and wind events that make the Presidential Range the most exposed section of the entire Appalachian Trail in shoulder seasons. The trail crosses above treeline for miles with no shelter. Spring comes late and fall comes early. What looks like a three-season trip to the White Mountains can turn into something far colder by nightfall.

The Mt Washington 3 is named for that mountain because the principle is the same in a hammock: bottom insulation is not optional once temperatures drop. This underquilt was built for the kind of nights where you're glad you planned for worse than the forecast.

Handmade in Pennsylvania by Jacks R Better — making quilts since 2004. In-stock quilts ship the same or next business day.

Specs: Mt Washington 3 20°F Hammock Underquilt