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Subaqua
07-26-2008, 09:03
With a tank (3442 psi), is it better to use a DIN or is it ok to use Yoke. I see a lot of people using a yoke with those kind of tanks, but I also heard that for HP, it's better to use DIN, so I'm a bit confuse. Can anyone explain it to me?
I'm thinking or buying my own tanks and hesitate between a al63 or steel 72 (faber Fx series). I'm open to any other suggestions, though.

Thanks

navyhmc
07-26-2008, 09:17
Din or Yoke? If your reg is a recent manufacturer, you are okay with a Yoke as they are engineered for the higher pressure. Personnaly, I prefer DIN for 3442. Just my personal preference. I like the retained o-ring and the more solid connection. One disadvantage with DIN is that if a tank is dropped and there is nothing in the valve, you can dent the openingand you will need to get a new valve as you may no longer be able to attach a din reg due to a opening that's no longer true. So get a steel/aluminum plug for your vavle if you go DIN.

ETA: The biggest difference between yoke and DIN is that with a yoke, all the strees exerted on the regulator is on the yoke and if the yoke suffers a failure, it is now a projectile. With a DIN, the pressure is distributed to all the threads and is a thus a more solid connection that is less prone to failing. This does not imply that a yoke is a poor connector, it's just not as safe with the higher pressures. I have yokes for 3000 psi and Din for higher.

There are also folks that like a DIN as there's less entanglement risk due to less stuff out there to catch lines.

As for your 63 or 72, unless you have a very low SAC, I would recommend an 80 as a minimum to allow for adequate bottom times.

Subaqua
07-26-2008, 09:37
thank you for your answer. My reg is a Titan Lx supreme bought in 2006, so I guess it's fine. My SAC is pretty good, compare with the persons with who I dive. With a 63 or even 50 I still end the dive with more air than others with 80. I don't want the 80, mostly because it's to long and heavy (I'm a tiny little woman). Since the tanks will be for local dive (Canada), I thought that maybe a steel tank could be a good option, since they have more air, in smaller tank. But then again, some are heavier, so I'm still analyzing the options.

Sansho
07-26-2008, 09:50
You might want to consider a steel HP 100 tank. It's a little shorter than the standard AL80, is the standard 7.25" width (impt if you go out on a boat with 7" racks), and while it can take a larger fill to around 3400 psi, a standard 3000 psi fill provides 89 cu ft of air. And, while an AL80's buoyancy ranges from -1 to +4 lbs (full to empty), a steel HP 100 ranges from -10 to -2.5 lbs, which means you can reduce the amount of lead weight you carry, too. ST's HP100 is at HP Steel 100 Scuba Tank High Pressure X7-100, Scuba Tanks, Worthington, HP Steel 100 Scuba Tank High Pressure X7-100 (http://scubatoys.com/store/detail.asp?product_id=X7100)

Edit: Seeing that you're looking for a smaller tank, how about an steel HP 80? It's 21" long (same as an AL63), empty weight is 28 lbs, 3000 psi fill gets you 72 cu ft, but can be filled to 3400 for full capacity, and has buoyancy from -9 to -3, so you can still reduce lead weight, compared to diving with an AL tank.

If you haven't seen this site, some good comparative AL vs steel information at Dive Rite Express -- How to Select a SCUBA Tank (http://www.diveriteexpress.com/library/tanks.shtml#recommendations)

navyhmc
07-26-2008, 09:57
Why didn't you mention the lady diver side? Like the t-shirt I saw once said: "My measurements? 3000 psi, 80 cubic feet and more bottom time than the guys."

The advantage of steel is that it is a bit more negative when full yet still negative when empty. An AL50 is about +1.4 empty, an AL62 is worse +2.6 empty. A steel 72 is -3.9 empty so that means less weight to carry.

Here's a full comparison:

AL50: 19" L, 6.9" dia, 21.2 lbs 3000 psi. -2.3 bls full, +1.4 lbs empty
AL63: 21.9" L, 7.25"dia, 26.7 lbs 3000 psi. -2.2 lbs full, +2.6 lbs empty

HP65: 16.7" L 7,25" dia, 25.1 lbs 3442 psi. -8.7 lbs full, -3.9 lbs empty

Hope this helps.

BSea
07-26-2008, 10:05
You might want to consider a steel HP 100 tank. It's a little shorter than the standard AL80, is the standard 7.25" width (impt if you go out on a boat with 7" racks), and while it can take a larger fill to around 3400 psi, a standard 3000 psi fill provides 89 cu ft of air. And, while an AL80's buoyancy ranges from -1 to +4 lbs (full to empty), a steel HP 100 ranges from -10 to -2.5 lbs, which means you can reduce the amount of lead weight you carry, too. ST's HP100 is at HP Steel 100 Scuba Tank High Pressure X7-100, Scuba Tanks, Worthington, HP Steel 100 Scuba Tank High Pressure X7-100 (http://scubatoys.com/store/detail.asp?product_id=X7100)

Edit: Seeing that you're looking for a smaller tank, how about an steel HP 80? It's 21" long (same as an AL63), empty weight is 28 lbs, 3000 psi fill gets you 72 cu ft, but can be filled to 3400 for full capacity, and has buoyancy from -9 to -3, so you can still reduce lead weight, compared to diving with an AL tank.

I agree with the steel 80. Several women from my lds use them because of the size & weight. Plus they give you more than an AL80 when filled properly. Many people don't know an AL 80 really holds about 77 cubic ft at 3000 psi. Plus with it being so negative, you'll really reduce the overall weight you carry.

You can convert your titan to din for about $50. If you do that be sure your LDS gives you back the Yoke parts. You can easily convert your reg to yoke for trips where you might rent tanks. If you convert to din, you should probably invest in a din to yoke converter (http://www.scubatoys.com/store/detail.asp?PRODUCT_ID=DinAdapter). I take 1 where ever I go diving, just in case.

Subaqua
07-28-2008, 10:24
Thank you for the comparison (is it for salt or fresh water?). So if I usually use between 8-12 pounds in fresh water, how much weight can I remove with a steel tank?