Do you really want to use an IPhone as a Scuba tool

An Iphone is an Iphone, a scuba computer is a scuba computer... I wouldn't want to use a multi-purpose phone for something that I have to depend on to save my life...

From Fourm: Scuba Toys
http://forum.scubatoys.com/computers-gauges-12/iphone-scuba-diving-37903/

The folks who were displaying the product at DEMA in November were taking preproduction orders for delivery in 2012.

Their product only worked with the current iPhone 4--I found out when I handed them my old original iPhone and was told that the unit would not work with it. (They also say that it works with the iPod, but I don't know what limitations are with that item.)

It struck me when examining it that this is a product in search of a market. I can easily see that this would chew through the battery life of an iPhone, since an always-on display uses a lot of juice--imagine being on a live-aboard with no means of recharging the phone.

Add that unless there is something in the system that turns off the iPhone's programming that makes it call for regular updates and/or scan for signal, battery life would be further eaten up by those functions..PLUS if a signal were detected, you might get a nasty surprise when overseas due to roaming charges you did not expect to have.