Excellent photographs, your helmet model has always called my attention, like the English pith helmet, could you tell me something about it?
Ok. Thank you!
Name's Vietnamese it is "Mũ Cối" (Motar Hat). Motar (Cối) is weapon of infantry. It's item become legend in Vietnam. If you to Vietnam, and you use a "Mũ Cối", Vietnamese think you is friend of them.
In history war. In WWI, army some country Euro (France, England, Japan...) use hats have shape nearly similar English pith. Hat use in enviroment tropics (
hot moist), when outdoor.
First "Mũ Cối"'s Vietnam, is product from China (Foreign aid to Vietnam), China Army not use it.
About function:
1/ Water container from river or lake... or rain in forest
2/ Wash-basin or hand-basin in outdoor
3/ Shape and structure's it help soldier feel cool, sun light and rain not impact direct their face. And have function camouflage.
4/ In fight with enemy. It's help soldier create hallucinations for enemy (fake head), when enemy ambush (sniper...). In enviroment war in city, it protect head of soldier not collision. And protect head of soldier avoid splinters.
5/ Soldier not use line rope of hat because when bullet fly to hat, with shape globular, it will spinning, decrease power of bullet.
....
About name's hat: It's "motar hat" because. When rain, soldier use hat cover mouth of motar gun (protect gun avoid rain). And shape's it similar motar (pestle and mortar), should name's it is "motar hat".