Tanks: HP100's

[BLT]

Hi,

Been doing some research on tanks. The HP100 seems like a nice option. If I understand correctly it has the same diameter as a AL80, is only a few inches shorter and has very nice weight/bouyancy characteristics. For common lake diving, a underfill to 3000psi gets you more air than the AL80 with no need to re-adjust tank straps if/when common rental AL80's are used.

Other than cost, the downside appears to be the HP100 being fitted with a DIN valve vs a Yoke valve. Is it possible to switch to a Yoke valve so a person can use their existing equipment? Can it be switched back to a DIN valve if a person buys a DIN-style primary in the future? Any thoughts/ideas would be appreciated.

- Brad

[DiveCaptDean]

Hey Brad,
Check into it further..You should be able to get the valve as a DIN with an insert that would allow you to use your reg.

[beeger]

Traditional high pressure steel cylinders come with a 7/8 UNF neck thread vs. 3/4 NPS for 3000 psi and lower for most other types. So, no, a regular yoke valve will not fit into a HP cylinder neck (for reasons beyond the scope of this message the 7/8 is actually *smaller* than the 3/4 neck size). There are convertible valves available that are actually a 200 (232) Bar DIN valve that allows for a yoke insert to be easily screwed in and out with without having to first drain the tank or anything like that. The convertible valves seem to only be available in the 3/4 neck size. I would assume that this is because the manufacturers don't want people putting these valves on HP cylinders. Keep in mind that the new Pressed Steel E-series cylinders which many people would consider HP cylinders actually have the 3/4 neck size.

Myself I like 300 Bar DIN. I use it on everything, and have for a number of years now. If I'm ever traveling someplace where I know I'll be diving cylinders with yoke valves I switch out the DIN kit on the reg I'm taking to the yoke fitting that came with the reg. This takes about 2 minutes, and any competent tech can show you how to do it on your own (no scuba-specific tools needed). You can also buy a simple, generic, spin on fitting for the reg DIN fitting that allows it to mate to a yoke valve. These take about 10 seconds to put on and can very easily be done at the dive site. I always have one in my save-a-dive/spare parts kit. The only disadvantage to the spin-on adapter being that it makes the first stage stick out a bit more than I like.

[Freedive WI]

You can also buy a simple, generic, spin on fitting for the reg DIN fitting that allows it to mate to a yoke valve.

That adaptor is designed for filling the tanks only- not underwater use. I have seen some people try to dive with them, but it is NOT a good idea.

Beeger was right on everything else, they don't make convertable valves for HP tanks- only those with 3/4" neck threads.

So, you either need to look into DIN adaptors for you reg's, or look into 3/4" neck tanks.

Jon

[beeger]

Actually what Jon is saying is not what I'm saying. What Jon is talking about is a DIN valve filler block that screws into the tank valve. These are meant for filling only and are not meant to be used for actual diving. What I'm talking about is an adaptor that spins on to any given DIN regulator to allow it to be used with a yoke valve. These are often sold under one manufacturer or another's brand name, but these are the same thing and fit any DIN reg. I'll try and find some pictures to show the difference.

[beeger]

Regulator Adapter:

Tank Valve Adapter for filling:
Go to "http://www.gmcscuba.com/main.php?content_url=ProductCatlog" then Section 5 > Tank Filling Aparatus > Tank Filling Adapters > 45185

[Freedive WI]

I've always called those a "yoke converter". They will allow you to convert a DIN regualtor over to use with a yoke valve, but it won't work the other way- as with the HP style of tanks.

I've always carried both in my spare parts kit- plus a couple of 200 bar valve plugs to use on 3/4" neck DIN valves.

Jon

[DiveCaptDean]

my bad

[BLT]

You lost me on that last reply?

So far I've learned one important thing if going the route of HP100's, Make sure they have a 3/4" neck so a Yoke valve can be directly used (right)?

And no, I don't plan on doing any dives with a DIN->Yoke fill adapter screwed on the tank!

My [albiet quick] search for a primary reg Yoke->DIN converter didn't turn up anything that looked safe/sturdy enough to consider using. I'll keep looking and if anyone comes across such a thing I would be interested.

I believe the item 'beeger' listed was the opposite of what I am looking for unless I missed something here.

If it helps any, I have a decent reg (ATX200) w/Yoke fitting. I think the only way I should even consider using it with a underfilled (3000psi) HP100 is with a directly installed tank Yoke valve.

The alternative isn't that bad. The money needed for (1) HP100 almost buys (2) AL80's. The HP100 just seemed like such a nice all round choice and good long term investment.

[jasondbaker]

How many and what type of tanks do you have now?

The DIN valve is an advantage. Removing it to put on a yoke valve is blasphemy. I recommend converting your first stage to DIN and then picking up a yoke converter for the warm water trips.