It wasn’t just secrecy it was also production capacity pretty much as soon as they could produce enough of them they started to use them on land as well. The pr

It wasn’t just secrecy it was also production capacity pretty much as soon as they could produce enough of them they started to use them on land as well. The proximity fuse was key to the US war in the pacific as well. It’s probably the main reason for why the US has dominated the electronics industry through the 20th century. The miniaturization required and the ability to mass produce electronics required the development of new production techniques. The proximity fuse was the first use of PCBs in mass production.