On Sun, 30 Jul 2006 00:16:39 GMT, Gary wrote:

We do use whistle signals but they don't agree with your "pass on two
whistles".

You will also hear things like "Let's meet on two whistles", meaning
starboard-to-starboard.

Is that an inland US rules thing?

Not sure but it is quite possible. I hear captains and harbor pilots
using similar terminology all up and down the east coast of the US.

I have also heard colors used as in "lets pass red-to-red meaning a
normal "one whistle" port-to-port" pass in an oncoming situation, or
something like "I'll pass on your red side", or, "I'll show you my
green light", that sort of thing. A lot of these guys in major
harbors seem to have known each other for years and probably develop a
common working vocabulary.