New Diver, New Computer

[dave of welly]

Dave,

Stop working so much and get to diving more...

I think the Mare Puck Pro will be a great first dive computer. Now go get it wet and blow some bubbles.

~Oldbear~

Haha I wish I didnt have to work, unfortunately I still have to buy regs!

Then maybe I'll quit work and become a full time seal

 

[dmaziuk]

The maximum ascent rates are stated and varied from 18-28 ft/min. I don't think this accounts for the performance of the Suunto, Mares, and Cressi computers

My (admittedly fuzzy) understanding is that the key to bubble models is inside/outside pressure differential. If goes above X, bubbles get too large to eliminate efficiently and you have to wait for them to get re-absorbed before you can off-gas "well". A "staircase" ascent could potentially push you over X during a "vertical" part. Then you'd have to sit longer at the "horizontal" part waiting for re-absorbtion to keep the model happy. Whereas if you did the same ascent in a smooth continuous line, you could stay below X at every point and end up off-gassing "better" according to the model.

It is a pure speculation on my part of course. All I know is that when I test for/at narrowly-defined specific conditions, the results prove what's gonna happen in those narrowly-defined specific conditions. They don't prove anything more.

 

[scubadada]

The ScubaLab testing is probably the best objective information we have. When Goingforsound posted the link to the data, he did not post the description of the testing. The protocol is a perfectly acceptable representation of 4 recreational dives done in a day with reasonable surface intervals and ascent rates. There is very little information available on repetitive dives. I find the results interesting and useful. There was quite a bit of variation between the 4 versions of RGBM, not unexpected as each is a proprietary design. Cressi was the most conservative. Suunto and Mares ran close to the Oceanic Buhlmann variant PZ+ in the middle. Atomic Aquatics ran reasonably close to Oceanic DSAT as the most liberal.

Personally, I hope this kind of testing is continued, expanded, and becomes more readily available. There are many more computers and algorithm choices I would like to see results for.

Objective Test Protocol

To gauge the performance of the computers’ algorithms, they were subjected together to a series of four dive simulations in the USC Catalina Hyperbaric Chamber.

Meant to simulate a day of diving, the dive profiles (shown in the four charts) were:

• 100 feet/60 minutes
• A one-hour surface interval
• 70 feet/45 minutes
• A two-hour surface interval
• 80 feet/45 minutes
• A one-hour surface interval
• 60 feet/40 minutes

The computers were placed in a tank of water inside the chamber, where a video camera was used to view and record each computer’s dive-screen data (listed in the spreadsheets).

Safety and conservative factors on the computers were set to their most liberal setting for the chamber dives. (In the case of Oceanic’s dual-logarithm OCi and ProPlus 3 computers, they were set to the PZ+ and DSAT logarithms respectively to gauge the differences between the algorithms.)

Note that while some computers display No Decompression Limit (NDL) data only in minutes (99 minutes) and others display hours and minutes (1:39), data is listed in the tables here in minutes only for clarity.

Special thanks to Catalina Chamber director Karl E. Huggins and chamber operators Paul Buechner, Scott Barnes and Kim Whiteside.

 

[Toriboo]

My zoop actually broke down after using it for a little over a year...

just bought a COSMIQ dive computer at ADEX, lovin the design and how easy it is to use! (only 2 buttons) Its got all the basic functions, and the price is unbeatable at $299.

According to the manager at the booth, they were doing a free shipping all over the world promotion but I don't know if its still going...

Here's the link to their site if youre interested--> www.deepblu.com