Whistle Signals

[HammerNoMore]

Am wondering if there is a set guideline for Whistle Signals on the surface and underwater? To let a buddy know you are ok, or need help, ect???

Or, do we need to make up our own signals pre-dive?

Your buddy should be close enough to you you don't need a whistle. On the surface a simple, "I'm OK" or, "Is my hair under my mask?", etc. should suffice. If you and your buddy are a long way from the boat and need their attention blow any way that will get it... It doesn't really matter what you blow, if they hear it they are going to assume you need some kind of help.

Underwater, if your buddy wont even hear the wistle unless he's pretty close (or it's metal and you use it to bang on your tank ). All you should need are hand signals. Basic ones are covered in your OW manaual. Here are some more:
http://waterfire.us/scuba/hand_signals.htm