Which doubles?

[parabuzzle]

No, I believe a drop weight is a weight you drop early in the dive, to be picked up at the end when you are lighter. This avoids the necessity to weight for empty tanks, where you are forced to begin the dive very negative. As my gas planning with thirds never gets me down far enough to worry about it, I have never used drop weights..

Yea, I only need the drop weight when diving wet to get me through that last 33 Feet and after air deco on back gas which is essentially twice? I think.

 

[aquaregia]

I only know of two shops in the SF Bay and Monterey areas that do tri-mix: AWS and Bamboo Reef, and AWS isn't convenient for me owing to their hours and location.

AquaSafaris in Santa Cruz has trimix.

 

[dannobee]

I thought the whole drop weight thing was the reason LP45 steel tanks were sometimes used in caves?

 

[Anti-Hero]

Cave diving makes my brain hurt.

 

[parabuzzle]

Cave diving makes my brain hurt.

Haha!

I wanted to be a cave diver since I was like 6 years old... My parents thought I was a crazy and it was only a phase.... they wouldn't even let me get my OW cert. When I turned 18 and graduated High School, I got 2 jobs and spent every penny I had on training and equipment for the better part of a year while I was trying to figure out what school to go to and what to study.. some phase huh?

 

[fdog]

Guy, I use both doubled Faber LP85's, and, doubled X7-100's. They are pretty indistinguishable, although if pressed, I'd put the Worthingtons as placing the weight a smidge more toward the shoulders.

Either way you can't go wrong. The Fabers are a bit easier to PP blend on top of leftovers; the extra volume of the 100's is nice to have for 18/45.

All the best, James


PS - I've felt the durability of the Worthington galvanized finish is better, too.

 

[Anti-Hero]

Ah, I forgot to add that, thanks FDog. I also was quite head heavy in my Worthington LP85's and use a 6lb. tail weight to offset the distribution.

 

[elan]

I was a bit unsure whether I should post this here, in the DIR or Hogarthian forums, or in the Tanks, bands and valves forum. But I figure most of our local tech divers follow one or all of these, so decided to try it here.

As many of you know, I plan to go tech so I can dive deep wrecks. I'll be taking Fundies in the not too distant future in a borrowed set of doubles and wing (thanks to Dan Bermingham), but as soon after that as money allows I'll want to buy a set of tanks that are more suitable for doubling than my Asahi 100s. From talking to numerous people and researching, I've narrowed down my choices for my first set of doubles to either HP100s or LP85s. Having perused spec sheets and figured out where I think my diving is likely to go, I've narrowed down my options to 4 different tanks from three manufacturers. In no particular order, they are: Faber LP85; Worthington LP85; PST E7-100; Worthington X7-100.

What is your height? If you are anywhere close to 6ft I would avoid all those tanks except Faber LP85 As the rest are shorter. I'm 6ft and I have troubles with the HP100s I can trim them with 4lb trim weight but it's not the best choice.

Do not think to far. My observation is that when people get to Tech2 level the set of bands is the last thing they think about I spoke to few people and the preferred sets for higher levels are AL80, LP104, HP130 as their tank factor divides by 2.5 more or less that is they can think about the gas in terms of stages. that is double AL80 is 2 stages, LP104 and HP130 have ~ 3 stages at 3000psi.

So you can start with AL80 doubles, they are cheap, long - trim well. But they are a bit buoyant so require lead, which you can spread for a good trim.

 

[Guy Alcala]

What is your height? If you are anywhere close to 6ft I would avoid all those tanks except Faber LP85 As the rest are shorter. I'm 6ft and I have troubles with the HP100s I can trim them with 4lb trim weight but it's not the best choice.

Thanks. As stated in the original post, I'm 6'/180 lb.

Do not think to far. My observation is that when people get to Tech2 level the set of bands is the last thing they think about I spoke to few people and the preferred sets for higher levels are AL80, LP104, HP130 as their tank factor divides by 2.5 more or less that is they can think about the gas in terms of stages. that is double AL80 is 2 stages, LP104 and HP130 have ~ 3 stages at 3000psi.

I figured that Tech 2 might well require something like HP130s (or my LP112s) for gas, which is why I wrote that this set of doubles only need to be suitable for Tech 1/1+.

So you can start with AL80 doubles, they are cheap, long - trim well. But they are a bit buoyant so require lead, which you can spread for a good trim.

The problem is that they require a _whole lot_ of lead to dive locally; even with my S/S BP I'd need another 12-14 lb. of lead, which makes the total weight far heavier than comparable steel doubles, and more than I want to use. I don't know of any local tech diver who uses Al80s, and I was ecstatic when I switched to steel tanks for my recreational diving; with my Asahi HP100s I dropped 9 lb. while gaining ~30% more gas. The Al80s do come in handy down the road for stage bottles so they aren't totally useless, but around here they don't make a lot of sense for doubles other than being inexpensive.

Guy

 

[Anti-Hero]

I know of one very skilled tech2-level diver that uses AL80's. But given his experience and profession he could probably dive with just about anything and make it look easy. And he's not a "big" person. Roughly Guy's height and weight I'd assume.