I don't know about anybody else, but when I finished my OW class, I knew I was to "plan my dive and dive my plan." What I didn't have much idea about was what a dive plan was, and how you made one. Other than saying, "Let's swim out here and wander around and see what's down there," I didn't know what needed to be in a plan. So I thought I would write something about what I've learned in the last year and a half about dive planning. (You can get MUCH more detailed and technical about it than what I am about to say, but this is aimed at a new diver headed out to do a shore dive in local water.)Pick your site, and then research it. "Research" sounds formidable, but it means finding out how to get there, what the parking's like, whether there are any facilities (restrooms, showers), whether there are any issues with access (limited time, physical barriers -- we have one local site where you have to cross railroad tracks to get to the entry!) Find out about hazards -- Do you need to take tides or currents into consideration? Are boats or fishermen typically present? See if there's a map of the dive site available somewhere. Something I learned is that divemasters often have to do a mapping project, so somewhere there are detailed underwater maps of popular sites. You can get some of this information from your local dive shop, or use shorediving.com, or Google the name of the dive site and see what you come up with. In the Seattle area, we have a good published book of shore dives, which has all this information in it.
What you learn about the site may affect what you decide to take with you -- for example, a dive flag or float, or a surface marker.
Once you have arrived at the site and rendezvoused with your buddy, take a few seconds to talk about things like where each of you is storing car keys and whether you have cell phones with emergency contact numbers programmed in them.
2) Decide the responsibilities of each diver. Who is going to lead? How are you going to position yourselves with respect to one another? Single file? Wing-on-wing? What signals are you going to use? (This is the time to make sure you signal numbers the same way!) This is the time to go through protocols like what you are going to do in the event you get separated. (Just a hint from my personal experience: If there is a photographer in the works, it's better if he leads.)
3) Where are you going to go? This includes talking about the topography of the dive site, compass headings if relevant, and what, if any, specific features you are going to look for.
4) Parameters for the dive: Max depth, direction (part of #3), anticipated duration. What's your ascent strategy going to be? (Ascent rate, stops if any -- where and for how long.)
5) Gas. Now that you've agreed on the nature of the dive and the proposed depth and rough duration, do you have the gas to do the dive? What is your required reserve? Shore diving almost always goes better if you plan to use half your useable gas going out and half coming back. (Nobody likes long surface swims!) Knowing your reserve and your gas plan tells you what your turn pressure should be. (See Rick Murchison's recent excellent
thread on gas planning for a much more detailed discussion of this.)
It sounds like a lot, but it actually goes pretty quickly, once you get the steps well established in your mind. A lot of annoyance (and some unpleasantness) underwater can be avoided by going through this stuff methodically.