MonkSeal
Contributor
If you're within NDL then you can surface with no deco stop (even without recomended safety stop) and you probably won't get bent. Although, I don't recommend such scenario. If you exceed NDL that's completely different story.
Suunto Vytec deco test... deco divers help.
- Thread starter jplacson
- Start date
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If you're within NDL then you can surface with no deco stop (even without recomended safety stop) and you probably won't get bent. Although, I don't recommend such scenario. If you exceed NDL that's completely different story.
That's where I figured further clarification was unecessary as he is obviously planning dives beyond my ability. I assume he must be a PadiTEC diver and knows no boundaries
MD
Hence my point about buoyancy control needing to be spot on.
People have rapidly ascended on a NDL dive and been bent. Others have done it on deco dives and not been bent.
ALL dives are deco dives, the maximum agency accepted ascent rates on NDL dives factor in for off gassing during the ascent. Ascend quicker than that and you stand a higher chance of getting bent.
If you cant control your buoyancy you shouldnt be diving lower than 80ft or so. If you CAN then a small amount of deco is no issue what so ever.
you should not be diving without professional, full-time supervision where you can be ASSURED of getting back to an upline - period.
Depth has nothing to do with it.
You will eventually have to make a free ascent due to missing an anchor or upline. I don't care how good you are, it will happen. When it does, if you cannot make a controlled ascent, you have a serious problem.
Depth has nothing to do with it.
You will eventually have to make a free ascent due to missing an anchor or upline. I don't care how good you are, it will happen. When it does, if you cannot make a controlled ascent, you have a serious problem.
OP
jplacson
Guest
Ok, a bit OT... I noticed a depth inaccuracy with my Vytec last weekend... I don't know if it's serious or just a normal thing.
How does water temp affect depth reading accuracy?
The error happened towards the end of the dive... after our safety stop... I was on my was up already, and I decided to play around with my buoyancy at around 7 feet.
At about 10', the water got really warm (looked like a thermocline...where the water vis gets all wavy and distorted) ... that's when my Vytec started reading shallower depths... 5', then... when I was at about 6', it read "0" ....
For the duration of the dive, it was fine... it was reading the same as a normal console depth gauge.
I rinsed it out in a wash basin, and checked it again in the basin... it read a 1' depth on the dot in the basin. I raised it a little above 1', and it read "0"... dropped it below 1', it read "1" ... so it seemed sensitive enough. Could the warm water have caused the error at the surface?
How does water temp affect depth reading accuracy?
The error happened towards the end of the dive... after our safety stop... I was on my was up already, and I decided to play around with my buoyancy at around 7 feet.
At about 10', the water got really warm (looked like a thermocline...where the water vis gets all wavy and distorted) ... that's when my Vytec started reading shallower depths... 5', then... when I was at about 6', it read "0" ....
For the duration of the dive, it was fine... it was reading the same as a normal console depth gauge.
I rinsed it out in a wash basin, and checked it again in the basin... it read a 1' depth on the dot in the basin. I raised it a little above 1', and it read "0"... dropped it below 1', it read "1" ... so it seemed sensitive enough. Could the warm water have caused the error at the surface?
Differing water temperature will have a different density therefore cause the depth display to read differently ( as its based purely on pressure) so in theory that could happen. Warmer water is less dense so theres less "pressure" on the sensor so it will read shallower.
Also fresh water mixing with salt water can cause this (fresh is less dense so would read shallower)
I havent bothered doing the maths but quite whether this could account for a 6' reading 0 i very much doubt.
I suspect variations of maybe 1-2ft would be possible but no more than that.
Also fresh water mixing with salt water can cause this (fresh is less dense so would read shallower)
I havent bothered doing the maths but quite whether this could account for a 6' reading 0 i very much doubt.
I suspect variations of maybe 1-2ft would be possible but no more than that.
OP
jplacson
Guest
Thanks String! 
1-2 feet sounds about right for thermocline changes... this was a significantly wider range of warm water, about a 3' thick blanket... and warm enough to distort vision... much like looking through those smoked/wavy bathroom glass doors! I was just worried that I got a defective unit.
But so far... fresh water tests seems fine... if the unit is sensitive enough to detect a 1' wash basin, I think it's fine. ... WHEW!
1-2 feet sounds about right for thermocline changes... this was a significantly wider range of warm water, about a 3' thick blanket... and warm enough to distort vision... much like looking through those smoked/wavy bathroom glass doors! I was just worried that I got a defective unit.But so far... fresh water tests seems fine... if the unit is sensitive enough to detect a 1' wash basin, I think it's fine. ... WHEW!
I suppose coming from cold salt water into a layer of much warmer fresh water would make a different, not 6ft difference though i dont think !. Incidentally, did you check your analogue gauge at the same time, it SHOULD read the same as the computer as it works on the same principle.
Very roughly ignoring salinity variations etc salt water is roughly 3% denser than fresh water of the same temperature.
Very roughly ignoring salinity variations etc salt water is roughly 3% denser than fresh water of the same temperature.
el-ninio
Contributor
I would not dive with this computer untill it was checked by a dealer - and if what you claim to have seen in true - untill it where replaced with a working unit. missing 6` may bend you, and there is no garenly that it will show anyhing remotly relaven to your avtual depth.
I've heard of simular problems form mosquito computers - in one such even I remember that the computer would show 9m at the serfice - and it had to be replaced.
dive safly
I know a number of people who use the gas-switching capabilities on the Vytec computer. They all say that it is quite simple to do, and to perform underwater - one of the nicest things about the Vytec is that the buttons are quite easy to use, even with your 7mm wet gloves or dry gloves on.
I must share the sentiments of many other posts in this thread though, and the thread-starter seems to understand this already too... going by just the vytec is NOT the way to go. As with almost every piece of equipment in scuba, using it without thinking is not conducive to doing it properly. Only by receiving proper training (whether through a shop or an experienced person) will allow you to plan and conduct diving activities safely.
On that note, all the people I know who use the Vytecs actually plan their dives using software and common sense and check those tables over. They use the Vytec as a bottom timer, but also as a backup device in case something hits the fan (or surface in this instance).
Myself, I have incurred some slight deco when diving with a buddy I deem 'safe' to do so with (safe would be a relative term here boys, so don't even start on that - see the quotation marks). We have done so using the Suunto mosquito, again using the same algorithm as the Vytec. Although we experience the same thing as all computer users, telling us to go to a much higher ceiling, we follow everything we know and understand from our readings, research, and answered questions - that of incurring a few deeper stops before ascending to the ceiling recommended on the computer.
Although you are enquiring about the Vytec, my mentioning of the mosquito is just to further the point that the RGBM model used by Suunto is exactly that: a model - similar to our tables and that no matter how good a model it is (and the suunto one is fairly good) it is never foolproof.
I must share the sentiments of many other posts in this thread though, and the thread-starter seems to understand this already too... going by just the vytec is NOT the way to go. As with almost every piece of equipment in scuba, using it without thinking is not conducive to doing it properly. Only by receiving proper training (whether through a shop or an experienced person) will allow you to plan and conduct diving activities safely.
On that note, all the people I know who use the Vytecs actually plan their dives using software and common sense and check those tables over. They use the Vytec as a bottom timer, but also as a backup device in case something hits the fan (or surface in this instance).
Myself, I have incurred some slight deco when diving with a buddy I deem 'safe' to do so with (safe would be a relative term here boys, so don't even start on that - see the quotation marks). We have done so using the Suunto mosquito, again using the same algorithm as the Vytec. Although we experience the same thing as all computer users, telling us to go to a much higher ceiling, we follow everything we know and understand from our readings, research, and answered questions - that of incurring a few deeper stops before ascending to the ceiling recommended on the computer.
Although you are enquiring about the Vytec, my mentioning of the mosquito is just to further the point that the RGBM model used by Suunto is exactly that: a model - similar to our tables and that no matter how good a model it is (and the suunto one is fairly good) it is never foolproof.
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