All radio transmitters had to be disabled while the ship was under any of the following conditions - being refuelled; refuelling aircraft; ammunition being loaded or unloaded; man aloft; ship being dressed; ship being lighted. When the keys were returned back to this panel, it signified that all radio transmitters and radar were secure. The key to the board was held by the Officer of the Day in harbour or the Officer of the Watch while at sea.
Safety precautions were also necessary whenever personnel were working aloft. Aloft, meant anyone working above the flag deck level. One hazard to be reckoned with was the fact that the 35 foot whip antenna presented a potential danger within a ten foot radius if the frequency was above 10 Mhz. From radar, there was a two-fold hazard. One had to worry about radiation and mechanical antenna rotation.
When aloft, it was stressed that safeguards must be taken against electrical shock, falling, choking from funnel gas and the dropping of tools. Personnel aloft had to be supervised at all times. There was a documented case in the United States Navy, of a man who was working aloft while the funnel exhaust was blowing his way. He worked in the fumes for a half hour and then came down complaining that he couldn't stand it any longer and would have to wait for the wind to change. About an hour later, he collapsed and was taken to hospital where he died later that day.
A colleague in my radio club decided to do some research after seeing
this story published in our local newsletter. Guess what - by today's standards,
maintaining a minimum distance of 10 feet from a whip antenna transmitting
at 10 Mhz higher is just about right from a personal safety viewpoint.