Natick Labs began development of the Tropical Combat Hat in 1966 after the U.S. Army Vietnam Tropical Combat Uniform Board unanimously agreed that the standard OG-106 field cap delivered inadequate sun protection.1 Based on a core design of a full brimmed hat with a band for attaching camouflage and a mosquito net the following three prototype models were fabricated:
One hundred hats in each style were sent to Vietnam in August 1966 to be evaluated by the members 1st Cavalry Division including personnel from the 1st Battalion of the 7th Cavalry.2 Though all models of the hat were well received, on the basis of troop preference and the estimated cost the T66-5 hat was recommended for general issue in November 1966 and was type classified as Standard A in September 1967.3
- T66-3: Felt lined full brimmed multiple stitched hat
- T66-4: Round domed full brimmed hat similar to Army fatigue cap of the 1930’s
- T66-5: Flat topped full brimmed hat made from similar material to the T66-4
The standardized jungle hat was made of OG-107 Oxford cotton cloth and had a 2½-inch wide brim with a flat-top crown. It featured an adjustable nylon lace chinstrap and had two ½-inch screened ventilation eyelets on each side. The hat also boasted a ¾-inch nylon-webbing headband for inserting natural camouflage. Unlike the earlier Jungle Hat and Mosquito Net issued to Special Forces, it did not have an internal pocket for the net.
Though it was developed as the Tropical Combat Hat and was issued as the Jungle Hat with Headnet, troops in Vietnam nicknamed it the Boonie Hat.4
1. Summary of Proceedings of United States Army, Vietnam...Tropical Combat Uniform Board. (22 November 1965)
2. Final Report of Tropical Combat Hats - ACL-84/67 (Army Concept Team In Vietnam Dec 1966)
3. Engineering Test Of Jungle Hat With Headnet Final Report (Robert C. Laughlin June 1968)
4. Boonies or Boondocks: Remote rual area; Wild and dense brush; Jungle.