Hosed or Hoseless, computer questions

[PfcAJ]

What's great about a hose is that I can replace it instantly pretty much anywhere in the world. The same can't be said about a transmitter.

 

[TSandM]

One of the big difference between "recreational" and technical diving is that in tech diving, the gas supply has been planned quite thoroughly before the dive is begun. You know your proposed bottom time and depth, and how much gas you will need, and how much you brought. The need to check gas every thirty seconds shouldn't be there, which is why just using a simple, clipped off gauge works fine.

That said, so long as you are not dependent on the transmitter, there are no horrible problems with using one, so long as you can orient it so that it doesn't interfere with reaching your valves, with hose routing, or present a significant risk of damage from impact. It does add a significant additional expense, however. And they can have some quirks that are particularly annoying to technical divers -- my husband's transmitter for his Vytech doesn't like valve drills, and has a significant rate of refusing to re-sync after he has shut a valve and emptied the line.

But I'm a little hypocritical in talking about expense, because I'm ABSOLUTELY an OLED fan -- the brightness makes the gauge readable for me in low light conditions WITHOUT bifocals, which to me is a safety thing. In addition, as I learned in my Full Cave class, in no light conditions, the amount put out by an X1 makes it possible to follow the line and see obstructions before you hit them, which is nice

 

[PfcAJ]

This is twice I've seen a comment about using OLED bottom timers as a light source in cave training.

The point of a lights out drill isn't to show you how dark it is. It's to teach you how to use the line to get out if you can't see (silt out, for instance). Cheating with your bottom timer isn't doing you any favors.

 

[Dr. Lecter]

We have been tracking failure of High Pressure( HP ) hoses ( dive computers w/ HP hoses & SPG's ) against failure of hoseless dive computers. The HP hoses are failing at about the same low rate as the transmitters.

Define "failure" for a HP hose. If it starts leaking during the dive, that's an annoyance to be sure, but it is still delivering correct pressure information. On a non-technical dive, some champagne bubbles from my HP hose/air spool/SPG assembly is not going to bother me in the least, though I'll fix it when I have a chance.

 

[CamG]

Greetings Aaron Beware to Nitek X my buddy had one and it did not work out very well for him lots of issues.
I am a huge Shearwater fan either of their computers would function well.
I have found that wrist computers work well for me in either Rec or Tec diving.
I like simple SPG on a 24 in. hose to keep tabs on my gas.

The ease of replacement is crazy easy I always carry extra's but have always done regular maintenance with no issues.
I have replaced and or loaned out several to friends but that is do to gear stowing / handling issues I believe.

In your choice it really depends on the the direction you are intending your diving to go.
Transmitters get bumped or struck on first stages if going into overheads.
I have witnessed some failures of the transmitters and if on a planned deco dive that would not be acceptable nor wise.
I have always recommended that if you are planning to train contact the instructor you plan to use and allow him to guide you in gear selection for the final purchase.
Sometimes he or she can give you the inside connections to get good deals but remember you do get what you pay for.
If you Tusa is a puck two gas computer you might be able to use it as a back up in gauge mode.
That is what my Nitex Duo now does with my primary being a Stand Alone Shearwater Preditor.

Good luck and again research is good if you can put your hands on a few different computers and see what will function the best for you.

CamG

 

[eelnoraa]

Since you ask for "tech" computer, I will suggest not to waste money on transmitter. Instead, must have are normal air/nitrox mode and gauge mode. OLED is definitely a plus for easy viewing. multiple gas is nice feature if it doesn't cause more.

 

[kelemvor]

I'm not tech or cave yet, however. I have the Galileo luna that has been discussed. The back-light included even with the large font is really insufficient even at just 100' in open water. I have to shine a light on it to read the thing. I love my computer but I wish it had a better display. I don't wear glasses or have any vision problems that I'm aware of. I'm hoseless only right now but when I take Cave 1 this winter I'll have a brass & glass on the other HP port at least. I would recommend getting one of those newfangled LCD or OLED computers, personally. I do love the hoseless feature of my Galileo, and wouldn't give that up for anything. I'm hoping when the time comes I can find a nice bright computer that also has a hoseless feature. Otherwise I guess it's the luna and a light.

I'm honestly surprised that there's not more animosity towards the Galileo in this thread. In the past, I've seen the techs take a dump all over it metaphorically speaking. I assume there is something that I'll learn in cave class that will make it completely undesirable.

That said, you do have the occasional disconnect between the computer and the tx with hoseless. It's not been a big deal for me, and might be attributed to the titanium in my neck near the transmitter. I assume that problem will apply to pretty much any hoseless, but I can't say for sure. I'm in the habit of checking the computer very frequently so I'm pretty on top of my remaining gas.

I REALLY wanted to go with a shearwater, but no hoseless feature was a deal breaker for me. FWIW, the Galileo does have gauge mode, and a lengthy "lockout" period. Meaning, if you do a dive on gauge, you can't go back to "computer" mode for 24 hours.

 

[Dr. Lecter]

I'm honestly surprised that there's not more animosity towards the Galileo in this thread. In the past, I've seen the techs take a dump all over it metaphorically speaking.

I haven't taken a dump on it here only because even BeaverDivers refrained from mentioning it...because it fails one of the OP's basic requirements: OLED or better display. He also said he wanted a tech computer, which IMO excludes the Galileo...but that's more stone throwing than objective fact Still, it has a lot of features that make it ill-suited to tech diving.

If you get through with Cave 1 and still insist on keeping a transmitter sticking off one of your regs during overhead dives, I'll be surprised. If you use the Galileo for deco diving with other divers in anything other than gage mode, I'll be even more surprised...and curious to know how you handle planning when you have a basically non-compatable alogrithm running on your Galileo.

 

[Centrals]

Two bottom timers + cut table and my brain as a back up.
If I need light then I simply switch on my torch.

 

[DevonDiver]

I can't think of any references I've ever seen where a technical training agency would positively recommend, or support, the use of a transmitter. Most (even PADI, shock, horror) recommend against them;

PADI Tech Deep Instructor Manual
Instrumentation

1. Basic deep technical rig instrumentation: SPG, compass, computer or timer/depth gauge and back up computer or timer/ depth gauge.

2. Technical divers generally prefer arm-mount instruments (generally SPG is not arm-mounted, though it can be) – consoles are bulky and protrude (doesn’t follow the standardized technical rig philosophy) creating drag and entanglement hazard. (Note: you can often mount two gauges on single wrist strap. Some tec divers carry back up instruments clipped inside a pouch or pocket.)

3. SPG (submersible pressure gauge)
a. One only (except in sidemount) – there is no back up (it creates two potential high pressure leaks); failure means end the dive immediately
b. Mechanical preferred – reliable with no battery concerns
c. In sidemount, smaller and lower profile preferred

...Note: SPGs are of the mechanical type. Few technical divers use air integrated SPGs to eliminate battery concerns. It is the one instrument that you do not have aback up for.

IMHO, the Shearwater Petrel is currently best on the market. Followed shortly thereafter by Liquivision's offerings. Cochran are runners up. Suunto's tech-level computers don't cut the mustard. There's a plethora of other computers on the market that call themselves 'tec', tech' or 'tek' - but they are in no way, shape, form or function capable technical diving devices...

The new X-Deep bottom-timer is causing a stir. It's user upgradeable - start as a bottom-timer, with upgrades to nitrox (>ER level diving) and then to full trimix.

Personally, I am not a big advocate of advising divers to invest in technical dive computers prior to training/qualification. For a start, most instructors/agencies will have you using tables/bottom-timers for training dives. Secondly, you need a good understanding of your technical diving needs and preferences... along with a good understanding of decompression theories and models.... before being able to make an intelligent, informed personal decision on what algorithms and functions your computer should possess.

Start by doing your training, to at least AN/DP or Tec45 level. Make sure to also read Mark Powell's 'Deco for Divers'. Then sink your teeth into more chunky texts that are available to read online. Then go a do a bunch of technical dives and see what works best for you. Learn to follow a planned 'run-time' with precision - it's an important skill. Find out how your local tech community/peers dive... see what they use. Establish what the common dive depths/profiles/considerations are. See what is the availability and cost of deco gases etc. This all has a bearing on what approach and/or alogrithms etc you will use. Then, and only then, invest a tonne of money on electronic instrumentation..