Both my wife and I are certified scuba divers—although as residents of the Pacific northwest, we don’t do as much diving as we’d like. We did just recently return from a trip to Bonaire, which was simply incredible, but that’s a story for another day. Becoming a certified scuba diver isn’t overly difficult, but you will spend a fair bit of time learning to read and interpret dive tables. When you first start diving, dive tables are a key tool in your portfolio—they tell you how long you can stay at a given depth, and more importantly, how long you can stay at a given depth on subsequent dives. (When you dive, your body retains nitrogen, which isn’t a good thing. Over time on the surface, this nitrogen is naturally cleared—so the longer you stay on the surface after your first dive, the longer your second dive can be.)
While dive tables work well, they’re a bit tricky to use, and subject to reading errors as you move down and across multiple columns, and flip the dive table from one side to the other. After learning to dive with tables, most scuba divers quickly move to dive computers, as they offer more power and much greater flexibility for divers, especially if you’re making multiple dives per day. However, dive tables are useful as backups, as dive computers can and do occasionally fail.
Dive Planner is a very simple tool, with three vertical sliders dominating its interface: Pressure Group (which represents the amount of nitrogen in your bloodstream at the start of a dive), Depth, and Minutes Down. A fourth horizontal slider lets you set the planned surface interval between dives. Two large buttons toggle between readouts in feet or meters, and two boxes contain your pressure group after the dive, and after the indicated surface interval. And really, that’s all there is. As you drag any of the sliders around, the pressure group readouts change to reflect the current settings. Compared to using a dive table, this is simplicity in action—a few quick finger drags, and you can see the pressure group for your current and planned dives.
About the only complaint I have with Dive Planner is that the horizontal slider for the surface interval can be somewhat difficult to “grab” with your finger tip, but this is a relatively minor issue. More importantly, I tested quite a few combinations of pressure groups, depths, dive times, and surface intervals, and all the resulting pressure groups matched with the values shown in my physical dive table.
While you might be tempted to take Dive Planner with you to a dive site, it’s really best used as a before- or after-dive planning tool—neither a dive boat nor a rental vehicle parked at a dive site are ideal spots to leave one’s sensitive and costly electronic devices. In its planning realm, though, Dive Planner works well, and it’s a heck of lot easier to read and use than any dive table I’ve ever seen.
Sure, dive computers are more powerful, more popular, and used by nearly everyone now. While Dive Planner won’t replace dive computers for complex plans, it works quite well—much better than dive tables—for simple dive calculations, and at $3, it’s quite the bargain.
Dive Planner is compatible with any iPhone or iPod touch running the iPhone 2.0 software update.
[When not diving, senior editor Rob Griffiths offers Leopard Tips at the Mac OS X Hints blog.]
Updated at 9:20am on September 3rd to reflect version 1.2 of Dive Planner, which reached the App Store on September 2nd. The new version replaced the three vertical sliders with the three rollers shown in the new screenshot, addressing my major complaint with the program. As such, the mouse rating has been increased to 4.5.