American Navy Sailors cap GI style, GI standing for general issue.
This hat also known as Dixie Cup Hat or Dog Bowl based on the shape of disposable cup or dog bowl one assumes.
While researching this hat I came across this fact that in April 2016 it was decided women in the US navy would be allowed to wear the same hat as their male counterparts, bit slow on equality there.
Made of white canvass, the white seems to have come about to help operations in hot climates or it could be because they were made from spare sail cloth, the latter seems more likely.
Practical hat
The brim can be flipped up to stop water running down your face into your eyes.
The brim can be turned down to protect your ears from sunburn or shield your eyes.
The hat can be used as a flotation device by capturing a pocket of air.
Can be stowed away flat since space on ships can be short in short supply.
This is cheap copy of an American Navy cap and is basically bush hat with the brim turned up, but looks similar enough to be sold as one. A bush hat in itself is based on fisherman's hat so this does lead back to source.
