Technically...

http://www.navcen.uscg.gov/mwv/navru...les/Rule34.htm

(d) When vessels in sight of one another are approaching each other and
from any cause either vessel fails to understand the intentions or actions
of the other, or is in doubt whether sufficient action is being taken by the
other to avoid collision, the vessel in doubt shall immediately indicate
such doubt by giving at least five short and rapid blasts on the whistle.
[Such / This] signal may be supplemented by at least five short and rapid
flashes.


--
"j" ganz @@
www.sailnow.com

"Charlie Morgan" wrote in message
...
On Wed, 2 Aug 2006 09:08:58 -0400, "Richard"
wrote:

Many short blasts means danger or imminent collision.


FIVE short blasts indicates either a danger alert, or a negative
response (No, don't make that maneuver!) to a signal from another boat
about their intentions.

CWM