Are Suuntos really more conservative for rec diving?

[flyingDiver75]

My experience with a Zoop was very similar vs Aqualung's current PZ+. Essentially same the 1st dive, consistently 11-12 minutes less NDL on the Zoop dive 2 after 1hr SI and diving 60-100' depths. I did around 20 dives with both to get a solid basis for comparison.

Dove a scuba pro ALadin and a ZOOP for a number of dives. Typical trip is 60-100 ft off a boat over a wreck or ledge. EAN 32 %, Multilevel. SI is about an hour. Tank is HP100. First dive they are about the same. Second dive ZOOP gave about 15 minutes less of NDL. On the second dive my dives are usually NDL limited and not air. ZOOP was also much slower in giving credit if I went up a little bit to get more NDL. Sold the ZOOP and now dive two Scubapros. Note: I do slow ascents, a full safety stop, etc etc. Also slow from the hang bar up.

 

[clownfishsydney]

My wife used to have a Tusa computer which was a rebadged Suunto. I used an Uwatec computer (various models). When diving multiple days, on the first dive the Uwatec was more conservative. On the second, the Sunnto was sometimes 10 minutes more conservative.

Once, when diving the wreck of the SS President Coolidge in Vanuatu (depth 20 to 70 metres), after about five days her computer decided it had had enough and she had dived too much. It gave ridiculous readings. She took over my backup Uwatec and used that for the rest of the trip.

Other than that, Suuntos are good computers.

My wife now has a Shearwater Predator which gives almost identical times to my Heinrichs Weichamp OSTC computers. If I were you, and money was not a problem, I would get the Shearwater (but not the watch type computer).

 

[vovanx]

I have compared NDL plans of Suunto RGBM and Buhlmann ZHL16c and found out that Suunto's default profile ("Personal 0, Altitude 0") is close to Buhlmann gradient factor 35/90:

algo | NDL/depth
Suunto RGBM | 68 49 34 27 20 16 12 9 8 6
ZHL16C 35/90 | 67 47 32 25 18 15 12 11 8 7

note that it is fully off-gased planning for the 1st dive.

 

[dmaziuk]

My experience with a Zoop was very similar vs Aqualung's current PZ+. Essentially same the 1st dive, consistently 11-12 minutes less NDL on the Zoop dive 2 after 1hr SI and diving 60-100' depths. I did around 20 dives with both to get a solid basis for comparison.

So if you dive to 100' for 20 min, spend 1 hour on the surface, and dive to 100' again, your Zoop's NDL is -1 minute? Or is it -2?

 

[Jay]

So if you dive to 100' for 20 min, spend 1 hour on the surface, and dive to 100' again, your Zoop's NDL is -1 minute? Or is it -2?

Our favourite topic!

Scubalab's data Dive 1, 100ft, 1hr SI, Dive 2 60ft, agrees with you in this case.

For those interested in various computer NDL comparisons have a look at the last page of this thread Place of dive tables in modern diving

and possibly have a read of this thread too: First Dive Computer ... it only takes a page or so to get spicy.

 

[flyingDiver75]

So if you dive to 100' for 20 min, spend 1 hour on the surface, and dive to 100' again, your Zoop's NDL is -1 minute? Or is it -2?

My comparisons were all based on Zoop vs Aqualung i300 (all of the current i series use the same algorithms so results would be similar with a i450, i200, etc). Profile for comparisons:
~85' 1st dive
65-70' 2nd dive
all on Nitrox 32
~1 hour surface interval +- a few minutes.

NDL's dive 1 were always within a few minutes. NDL's dive 2 were always 11 - 12 minutes longer on the i300 vs the zoop. This was fairly independent of the exact profile and time of dive 1 and the initial NDL time available on reaching depth at the start of dive 2.