Bottom Timer vs Dive Computer

[KeithG]

A bottom timer will tell you depth (max) and time in the water. Some will give ascent info. A depth timer may or may not be a computer. My first gauge was a depth gauge / bottom timer. I used it for square and multi-level dives.

Some of the more modern computers can be anything based on the software. So a BT can be come a dive computer.

There appear to be various flavours of "bottom timers".

Most basic is a waterproof "stop watch". i use an elcheapo $25 timex for this.

Next step up is a multi dive timer. My sherwood bottom timer is pressure activated, counts the number of dives in last 24 hours, displays surface interval time and bottom duration of current / last dive.

Next step up would be something like the uwatec bottom timer which also includes a pressure sensor to record maximum depth.

 

[Lorenzoid]

There appear to be various flavours of "bottom timers".

Most basic is a waterproof "stop watch". i use an elcheapo $25 timex for this.

Next step up is a multi dive timer. My sherwood bottom timer is pressure activated, counts the number of dives in last 24 hours, displays surface interval time and bottom duration of current / last dive.

Next step up would be something like the uwatec bottom timer which also includes a pressure sensor to record maximum depth.

Well put. And if one really wants to rank the various types of instruments that are "bottom timers" from Timex watch on up in terms of sophistication, then even above the Uwatec bottom timer I would add dive computer to the list. A dive computer is a bottom timer, though most people don't think of it that way because the whole point of having a dive computer is to let it compute decompression information for you.


It's occurred to me that maybe the original question here was prompted by requirements for taking a course. If you take a course in which you're going to learn to use tables or some other method of determining decompression information other than a dive computer, the instructor might tell you to bring with you to class, at a minimum, "a bottom timer and a depth gauge." From what I've seen, instructors will say a dive computer serves just fine as a combined bottom timer and depth gauge for purposes of such a course. (Just like the Uwatec.) You could switch a dive computer to gauge mode during class if it has such a mode, but it's not absolutely necessary--so long as the thing displays your bottom time, it's a "bottom timer."

 

[KevinNM]

You could switch a dive computer to gauge mode during class if it has such a mode, but it's not absolutely necessary--so long as the thing displays your bottom time, it's a "bottom timer."

As long as you don't lock it out. Which apparently can happen if you are using totally different gasses than the computer thinks and a chart developed with a different deco algorithm than your computer uses.

 

[KeithG]

Well put. And if one really wants to rank the various types of instruments that are "bottom timers" from Timex watch on up in terms of sophistication, then even above the Uwatec bottom timer I would add dive computer to the list. A dive computer is a bottom timer, though most people don't think of it that way because the whole point of having a dive computer is to let it compute decompression information for you.


It's occurred to me that maybe the original question here was prompted by requirements for taking a course. If you take a course in which you're going to learn to use tables or some other method of determining decompression information other than a dive computer, the instructor might tell you to bring with you to class, at a minimum, "a bottom timer and a depth gauge." From what I've seen, instructors will say a dive computer serves just fine as a combined bottom timer and depth gauge for purposes of such a course. (Just like the Uwatec.) You could switch a dive computer to gauge mode during class if it has such a mode, but it's not absolutely necessary--so long as the thing displays your bottom time, it's a "bottom timer."

I discovered 1 bonus of the timex watch during our last trip - it will tell me when lunch time is! Since it is a watch, it also serves as a watch. unfortunately it's factory programming appears to include the awesome "beep every hour" feature. took me a few dives to figure out I was the "beeping idiot". I now have a todo to try and figure out how to stop it from beeping every hour.

 

[scubadada]

Use a bottom timer if you want to dive tables, dive a computer if you want to take advantage of your true nitrogen exposure, i.e., the multilevel dive

 

[Bob DBF]

Use a bottom timer if you want to dive tables, dive a computer if you want to take advantage of your true nitrogen exposure, i.e., the multilevel dive

Or a Wheel.


Bob

 

[MT_Dweller]

Thanks for the clarification all

 

[TimTheDivenchanter]

Now to add another related question to this thread. If I need a redundant source of info to my main computer in case of emergency.(I dive with Shearwater Peregrine Tx) Do you think a bottom timer like the scubapro 330M or a cheaper computer would be better.

 

[scubadada]

Wow, thread from over 9 years ago, and I was in it then.

I would choose a backup computer to give you the advantage of your true nitrogen exposure and a multilevel dive. A bottom time limits you to a square profile/tables.

You didn't say what GFs you use for your Peregrine TX. Keep in mind that your more conservative computer will control your dive if avoiding deco.

 

[boulderjohn]

How would a bottom timer help in an emergency?

Assuming you are talking about an NDL dive, you would simply ascend if your computer failed. If you are planning to do a second dive, the bottom timer can only help if your earlier dive was not multi-level enough to exceed table NDLs and you had tables with you.