Bottom timers

Occasionally I see references to bottom timers, but I am unclear what is meant. I know that there are watches (mechanical with a rotatable bezel or digital with stop watch feature) that can measure bottom time, and I know that there are dive computers, but is there a separate piece of equipment known as a bottom timer? Or does bottom timer simply mean one of the foregoing?

Ricky,

It usually refers to a combination depth gauge and bottom timer (digital), such as a Uwatec/OMS brand bottom timer. There's also now a liquivision Xen bottom timer, as well as a newer version of the uwatec.
You're right "bottom timer" would seem to mean any type of wrist watch. But most people are referring to one of the digital depth gauge/timers.

An alternative is a regular computer set to "gauge mode".

-Mitch

Back in the early 80's or perhaps earlier Prinston techtonics "Bottom Timer" came out, it was a windup timer that automaticly started at 5' depth and timed untill you came back up to 5'. It was used instead of a watch, low tech and mine still works. With the advent of electronics, the new bottom timers can do more in less space and it is history. The genaric name bottom timer probably came from that brand name, as we use klenex or xerox.

this is a link to one on ebay:
VINTAGE orange PRINCETON TECTRONICS BOTTOM TIMER,GLOWS | eBay


Bob
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I may be old, but I’m not dead yet.

The term "bottom timer" is generally used for something which displays depth and time, but does not give any decompression information. Bottom timers are used by technical divers and by others who are diving tables or using some other method for determining their decompression status. There are a couple of dedicated bottom timers made (meaning they have no method at all for calculating decompression status), and of course there are dive watches that have depth gauges. In addition, some people run their dive computers in "gauge mode", which means they do not process nitrogen loading, although they have the capacity to do so if set differently.

Bottom timers are a digital or analog way to measure depth and dive time. They tend to be cheaper than a full computer. People who calculate their dives with tables use these. Also, they are very popular in my area as "back up" devices. In other words, a person can use a computer and a bottom timer so if the computer dies they can still finish their dives safely based on tables and bottom timer info. If the bottom timer fails you still have the computer. It is much cheaper than buying two computers and is a very safe way to dive. Also, you won't have to miss dives because your computer battery dies.

PS- They are also popular with some free divers who are intrested in knowing how deep and how long they stay under.

Hope this helps and dive safe!

I ordered a Princeton tec mechanical bottom timer from these folks yesterday:

Brass Anchor Scuba Center Frederick PADI Courses

I think they have one left.

For the kind of diving I do (weekend, 2 dives a day, shore diver) I've never seen the need for anything more (though I have rented a computer for longer live aboard trips).