Radios: Do you know what's what? Everyone please read.

[nigel]

Do you know how to switch our vhf radios on?

The accompanying photos show our vhf radio number 1, opened up to find out what had happened to cause the radio to dramatically short out the battery and fail.
The second photo shows the circuit board in the proximity of the battery connector,, and what happens when sea water gets inside the vhf radio.
How did salt water get there?

Look at the top of the photo of the whole radio. There is the aerial ( the pencil- like object sticking out of the  top), and beside it a little stubby knob.
THAT KNOB IS A WATERPROOF COVER FOR A SERVICE JACK PLUG.
IF YOU TURN THIS KNOB (in the mistaken belief that it is an ON-OFF, or VOLUME KNOB, you break the waterproof seal -AND SEAWATER CAN ENTER THE VHF,
That is what happened today.

The ON-OFF switch is a blue push-button on the SIDE of the radio ( smaller than the blue PUSH-TO -TALK button just above it).

This radio may be recoverable but, once seawater has entered the internal circuitry, it starts an essentially unstoppable process of corrosion - however well it is cleaned and neutralised.
Assuming I can get it working again, this radio has now got a probable lifetime of 12 to 18 months.
A replacement will cost in the region of £150.
Please don't open up radios, or twiddle knobs if you aren't sure what they do!