Why cab 11, 12, 13?

[David_Hayward (RIP)]

Basically, the type of cab was determined and set down as to closed or open, for whatever vehicle. So the first closed cab was the Type or Number 11, and the open version 41. However I have never seen a 41 Cab! The next type, with alligator hood was therefore the Type/Number 12 Cab, and its open equivalent the 42, as used on the Chevrolet 2-pounder Portees. By the end of 1940 the last general type of cab had been decided upon, which became the Type/Number 13 and the open version was the 43, as used say on the Chevrolet 6-pounder Portees. A variation of the 43 cab was the 43S for the F30B Bofors.