On 7-Feb-2005, Richard Ferguson wrote:

I would suggest two seconds for
shorts, six seconds for longs, with at least two seconds between toots,
maybe 10 seconds between the shorts and the longs.

At that length, folks might not think it's a signal. One SOS over a
minute long (62 seconds to be precise)!

I'd suggest a lot shorter. Less than a second for a short, about twice
that for a long. Short gaps between each toot and longer between
each repeat.

If there is any chance for echoes, it may all sound like a mess of confusing
sounds. For that reason, three toots is somewhat better than SOS in Morse.
Also, that means that signalling with a whistle for any reason but distress
should be discouraged.

Mike