A bridge always had one radio tuned to the distress frequency.

For much of the 20th century, 500 kHz was the primary international distress frequency.

It does not use the international distress frequency.

Lots of them don't carry any radio at all and even those who do almost certainly wouldn't be permanently tuned to the distress frequency.

Here's the text of that transmission on the international distress frequency.

Station operators also monitored the international distress frequencies for calls from ships in trouble.

They are generally designed to transmit on international distress frequencies.

I'd just time to change to distress frequency and bang out a couple of maydays.

She'd already radioed a mayday on the international distress frequency.

Other international distress frequencies, in use as of 2008, include: