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Tech diving

Thread Status: Hello , There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.

Jay Styron

New Member
Aug 31, 2001
Aren't there any tech divers on this site, I know there are. Lets get this thread started.
Mounting Twins


Any opinions on the best way to mount twins, by that I mean two
air tanks, although other options do come to mind. It has been quite common for sport divers to mount the tanks valves up, however some military and the Brits often go the other way. Also there are a couple of new valve protectors on the market, thus making it safer to mount the tanks valve down, without great worries about rocket rides.

Any thoughts?

Tank setups

Hi Jay & FD48
I was starting to think I was the only techie out here!! FD48 - I've used tanks "upside down" and really the only difference is that you've got to rig you're hoses differently. the DV hoses have to be longer and the guage hoses shorter or they keep getting in the way. You also have to do a few dives to get used to them before going for the deep ones But are much easier to shut off/open up.
I used the upside down ones in the navy and the reason they were rigged like that was because we didn't use guages and so we breathed one tank down (the other was shut off) and on feeling resistance we opened up the full tank, let it equalize, and shut it off again. We breathed down that half tank and on feeling resistance opened up the 2nd tank again and so we knew we had half a tank to suface on. Of course these were shallow dives to a max of 21meters. Do you guys trimix? Say, don't I recognise you guys from the freedive forums! :D
valves up

Hi Lou,

Thanks for the comments. I run mine up largely to protect the valves, but I must admit that I would prefer an easier/faster shut down sequence after reading the article in Diver last month. The gas loss stats were enlightening. I'm sneaking up on trimix so that I can back-up the freedivers.

Best wishes,

I tired a set of double LP 120's mounted upside down one time about 10 years ago. The idea was to be able to get to the valves easier. THey had a mounting bracket attached to them so they could be stood up. I didn't like the set-up because it messed up my trim too much. It made my bottom so heavy that I dragged my fins when I swam.
LP 120s

Hi Jon,

Those are some big tanks, did you ever try a set valves up? I wonder if they may not cause your fins to drag as well. I use hp 50s which make a nice little bundle.

I've used double 112's valves up with out any problems. The 120's belonged to another diver who let me try them out.
On a normal dive I use hp 100's or a freind's lp 95's. The 95's seem to swim better in the water- better trim. The 100's were so cheap that I couldn't pass them up. The don't swim as nice, but I use them all the time for scuba.
favorite tanks

Hi Jon,

My all time favorite tanks were LP 82s made for the US Coast Guard, they had cast in bases. Each tank new was $30.00, which included a k valve. I wish I still had them. Now my favorite tank is a 1965 Internaltional Divers LP 72, it is a great swimmer. I had two of them but its partner failed the visual badly last summer, even after way too much tumbling. Most of the twin divers here prefer twin LP 72s.

I still have an old 72 that I use for single tank diving. I have the double 100's for deeper stuff and I have turned both of my aluminum 80's into stage bottles.
My father-in-law has these 35 year old steel 94.6's that he likes. The things are so heavy that we really don't need any extra weight with them, even in a drysuit.
On the charter boat I work on we have some lp 80's in rental that work pretty well.
Down in the islands I like to use an aluminum 50 for most dives.
For the first 10 years, or so, that I dove I used steel 72's all of the time. If you only have acess to a small compressor they hold more gas than an 80.
A lot of my friends like the lp 85's. They double them up for most of their diving. The only good thing about the 112's was that you could get two deep dives out of them without refilling. Otherwise they were just to much hassel to carry around all the time.
THe one real side benifit to freediving is how much gas I use now. THe more often I freedive the smaller tank I can use when I go back on scuba- unless I have a hacksaw with me.;)

tech/freedive suit

Hi Jon,

I think I remember getting about 12 minutes out of a LP72 at 60'
cutting a drive shaft, hack saws suck air.

The water is pretty cold here right now and my 7mm doesn't do it for very long. I froze my butt on friday, but part of it was recovering from a cold. It got me to thinking though about a dry suit set-up. One would weight to be negative on the surface unless there is air in the suit, gas it for breathe-up, and then dump it to dive and gas it on the bottom for neutral bouancy, and again on ascent for lift. It would be a good exercise in bouancy control if nothing else. A small argon bottle would likely suffice with a pressure guage on it. One would not want to do this with a cold, the rides could be pretty fast depending on the weighting/lift. It would be like a portable no limits set-up. Just don't breathe the argon or there could be some real interesting rides.

I have tried to freedive with my drysuits in the past, but without the argon bottle attached.
I could get down about 20' in my old Viking with the foam underwear before the squeeze would kill me.
My old DUI TLS-350 with C-4 thinsulate worked out a little bit better. I could almost get to 30'! The suit squeeze was pretty tremendous is some very key spots.:waterwork
I was supposed to go out wreckdiving on Lake Michigan today. The wind has been blowing pretty hard for the past 3 days and the waves are breaking over the outer harbor breakwall. Maybe next week will be better.
It would be interesting to get a pair of those open heeled Sporasub fins to put on over the drysuit boots. My argon bottle is pretty small, only 6 cuft., so I could easily strap it on to my belt.
THis could be something to work on for next year. If I bought another pair of fins right now I think my wife would kill me.
I keep dropping hints to her that a monofin is in my future sometime in the next year.:D

Tech Dives

Hi Guys and Ladies (if there happens to be any reading this)
I knew there were some tech divers out there. I've never used tanks in the upside down system but would like to try it sometime. Shut downs aren't too bad now but that seems like it would be easier. You can also sidemount your tanks if you are going into tight places. We use LP 120's, 112's, 104's, and 98's. I usually stick w/ the 112's and 104's. We also use 72's, 80's and 45's for stages.
Most of our diving is on deep wrecks and geological features that the scientist want info on. We're definately going from one extreme to another, trimix to freediving. Take care everyone and good to hear from you.
Great Lakes in the Winter

Hi Jon,

I started diving in Lake Huron, in 1964. at Alpena, Michigan.
It was a great place to dive there were something like 160 wrecks
just in Thunder Bay, which is where Alpena is located. We had a small salvage outfit at the time, today they would call us thieves.
I also remember being able to speed skate out to some of the islands this time of year, that fresh water gets pretty hard sometimes. I remember the breakwall totally loaded with ice, it gives me the shivers just thinking about it, but I understand Michigan and Superior are much warmer, not!

...thought I'd sneak over here from the freedive areas.

My favorite tanks ared the HP 80's I' currently using. They don't knock my noggin when I arch back and they let my hips rotate and roll freely when I'm doing the lambada for lobster. They hold enough air to get in trouble with and are nice, tidy and small. Kinda like the ideal woman...

I will, however express an affection for the AGA units made in the late 70's and 80's with their twin HP yanks and the valves on the bottom with the fiberglass handle/yoke. Those were really nice swimmers. I'd be pretty tickled to hear if they were still around as the comm units in the full face masks were good too, a consideration I'm looking at so I can yak with my kids now that they're wet with me.

To that end, I posted a query about current comm units in the SCUBA section but no takers. Comments from you folks?

The aga's are still around. We have a hard wired unit that we use once in a while. The mask uses more gas than a cressi full-face or a regular half mask. I think that the local dive rescue teams are using the OTS system. They have some aga's and some exo-26's that they use.
Are the new OMS 46's similar to the old aga tanks? I know that they can be manifolded and slung however you want.

Lake Huron has some of the prettiest wrecks that I have seen. I was on the Newel Eddy not too long after she was found. It was great to start at the top of the mast(38') and spiral down to the crow's nest (90'), then continue down to the main deck at 150. I think that she bottomed out at about 167', or something close. She had so much stuff on her back then.
All of the lakes have cleared up quite a bit thanks to the zebra mussles. When I started diving lake Michigan we never had more than 5-8' of vis. If it got up to 15' people closed down their shops to dive.:D
Now, I have actually measured out 80' of visibility in the winter time. Summer will often bring about 40'-60' on a pretty regular basis. When you get to the deepr wrecks, past 160', the vis can get up to 30' but is usually down around 8-10'. The depths that I freedive to, 60-100', the vis is always a good 30-40'.
When I lived in Milwaukee we would do salvage jobs to supplment the charters and scuba classes that we ran.

Lake Huron Viz

Hi Jon,

That is pretty good viz, I remember 20-40 being kind of typical back when I was diving there. The cool part of low viz wreck diving is that we never knew what we would find on the first dive.
On a good day our buddy would fly early and drop bleach bottle markers on dark spots and we would follow them up on the water. On a typical day we would drive the boat around likely wreck water and dive blips on the sounder. It was so cool to see the ribs of an old schooner sticking up from the bottom for the first time. Those expereinces have really dulled my interest in artificial reefs, but the fish seem to like them.

AGA masks


Hey there tech boyz

My husband was once into tech diving, but then found enlightenment in the freediving with out gear. However, I am a GEAR PIG and have inherited all of his old gear. I dive with twin steel 50's and have a nice rig. I have taken a few courses, and am ready to take the trimix course. I eventually want to get into Cavern and Cave diving.. as well as Deep Wreck penetration diving. Not too many courses around where I am though, and I am not in an area where there is any deep diving. you have to go on a boat out 2 hours to get to water that is over 60 feet deep.

I will however, be moving to Indonesia, and am looking forward to diving there. Anyone know of courses offered in that area of the world for techies?

I want to buy some new regs... and was looking at the Zeagle, Apex regs... are there better ones out there for me? I also am looking for a computer that I can do some mixed gas diving with... for the future. I want to be able to have a computer that would be able to calculate all of my deco stops using different gases, and not penalizing me for deco with say 100% O2 after 70... anyone got suggestions?

Thanks... great to see some tech talk....
AND YES.. there are some ladies out here looking at the site!
think deep
regulators, computers, ect.

Welcome to the forum Neeka.
I use Apex TX-50 D severes on my doubles. I have cheap Dacor regs on my stage bottles and argon set up. If I had the cash I would switch all of my regs to DS-4 first stages and TX-50 second stages. They have been some of the most reiliable for my freinds and I diving the Great Lakes year round. I think that many of the deep cave records are also set on them.
Forget about a trimix computer. Use your Misquito's bottom timer function instead. You can get deco planner in a palm pilot version now off of the GUE web site. That way you can plan your dives on the spot and not waste a lot of money on a big dive computer that needs a bottom timer to back it up anyhow.
I would like to cross over to freediving fully, like your husband, but tech divers are a lot eaiser to find around these parts than freedivers.:head
Maybe all of that will change in the future.

Take care,

OK I´m a GEAR PIG to,happy to see another woman with the same "problem", what a luck to inherit all those things that cost a fortune.Having more time in front of the computer than in the sea made me find a lot of links that might intrest, hope something will help you.

The GUE site http://www.gue.com/
Apex http://www.apeks.co.uk/
ANDI , maby tou can find someone close to you that give courses
NAUI , have gone tec to http://www.nauitec.com/
DIVER had a test of regs in the last number,it usally takes a month before it comes on the net.One of those testing is a female tecdiver that alsoe writes in Divegirl
Immersed a tecdivingmagasine, they have a gearlink http://www.immersed.com/
Good luck with the trimix corse, let us know how it goes.And feel fre to mail me if you find some gear that improves the quality of life...

Apeks 50's

I have been diving since the mid 60's and switched from Scuba Pro regs years ago to
the Apeks T 50's on all my technical and recreational gear.
I've never had a problem with them in fresh, salt, cold or warm water on any mix.
I do use them exclusively on all cylinders even my stages.
The last regulator that was not an Apeks had a 1st stage fail at a 190' stop, I stitched
one of my DIN Apeks from my bottom mix over to it underwater (press your purge
button before you turn the valve on our you will have a bent regualtor) and completed
all my stops. After returning to the boat I put the regulator in a bucket of water and
rebuilt it back at my shop.

Can't say enough about how good Apeks has been to me over the years.

I too use bottom timers but have demo'd the OMS trimix computers in the past, nice
piece of gear.

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