An Island full of holes

[marine521]

Last weekend we went with a friend for diving just outside Athens. There is a small island called Dounis Island.

The island beneath is like swiss chease full of holes and we decided to explore some of them. We found out later that some of the caverns (if i am describing them correct) continue far more deep into caves...


We didnt enter because I am not qualified not trained for this sort of diving...(but i would pretty much like to do so)...

This is actually my first experience in overhead environment (caves or caverns you name it) and I must admit I am thrilled about it...

There is a Link with some photos of where we went (I am sorry about the pictures quality)

http://www.huts.gr/modules.php?name=...pic&t=220#1366

And one question
I checked my depth meter gauge and it showed one meter less than my watch depth meter... Is this normal?

 

[victor]

To how many decimal places do they read. If watch is 0.1 and depth guage is to the metre then the difference may be perfectly normal.
To do a realistic comparison you need to hold them beside each other while you descend continuously comparing the results.

 

[marine521]

To how many decimal places do they read. If watch is 0.1 and depth guage is to the metre then the difference may be perfectly normal.
To do a realistic comparison you need to hold them beside each other while you descend continuously comparing the results.

the depth gauge is analogue and my hand wrist watch is digital... The difference was exactly 1 meter because i hold the beside each other but when I was at the bottom.

I will do that next time i go diving and I will see what are the readings.

 

[Tamas]

the depth gauge is analogue and my hand wrist watch is digital... The difference was exactly 1 meter because i hold the beside each other but when I was at the bottom.

I will do that next time i go diving and I will see what are the readings.

possible that one is calibrated for salt water while the other for fresh?

 

[marine521]

possible that one is calibrated for salt water while the other for fresh?

Dont know, my watch is a Citizen Aqualand and the Gauge is a Tigulio which i bought two months ago...

The thing is that i did some dives recently and I havent noticed it. I did notice it though on my last dive in sea water

 

[ZzzKing]

Dont know, my watch is a Citizen Aqualand and the Gauge is a Tigulio which i bought two months ago...

The thing is that i did some dives recently and I havent noticed it. I did notice it though on my last dive in sea water

I have an Aqualand with just the guage hand that looks like a second hand. It seems pretty close to the reading I am getting from my Mosquito but since it is a hand, it doesn't really give an exact depth reading. If I were you, I'd believe whichever one gives the most conservative (deeper) reading.

 

[marine521]

If I were you, I'd believe whichever one gives the most conservative (deeper) reading.

Thats exactly what I did... I will check next time during descending though to check it out

 

[mfalco]

On the deep dive for my AOW course we had to compare the depths on everyones gauges and computers. It was to show us that different equipment gives slightly different values.

 

[marine521]

On the deep dive for my AOW course we had to compare the depths on everyones gauges and computers. It was to show us that different equipment gives slightly different values.

and how much was the "slightly" ?

 

[miketsp]

..snip..
And one question
I checked my depth meter gauge and it showed one meter less than my watch depth meter... Is this normal?

Just possible if you were below 15m.

Typical depth sensors are +/- 3% so if one was at the top limit and the other at the lower limit you could have a 6% difference.

My Citizen watch and my Vyper agree pretty well. Less than 1% difference between them. Note that the Vyper spec is much better than the watch spec.

Citizen spec:
Depth gauge accuracy: ± (3% of displayed value + 0.3 m (1 ft)) (when used at a
constant temperature)
Guaranteed accuracy temperature range: +10°C to +40°C (50°F to 104°F) (accuracy
of water depth measurement is affected by changes in ambient temperature)
Water depth measurement range: 1.0 m (4 ft) to 80.0 m (266 ft)
Water temperature measurement accuracy: Displayed value ±3°C (6°F)

Vyper spec:
Depth Gauge:
• Temperature compensated pressure sensor
• Salt water calibrated, in fresh water the readings are about 3% smaller
(calibrated complying with prEN 13319)
• Maximum depth of operation: 80 m [262 ft] (complying with prEN
13319)
• Accuracy: ± 1% of full scale or better from 0 to 80 m [262 ft] at 20°C
[68°F] (complying with prEN 13319)
• Depth display range: 0 … 100 m [328 ft] (over range up to 150 m [492
ft] in an emergency situation)
• Resolution: 0.1 m from 0 to 100 m [1 ft from 0 to 328 ft]