Tank decision; depth/cold of chartered dives?

[jchaplain]

Why? Because you usually don't need the extra gas. On any >100' dives, I'm NDL limited, not gas limited (and that's with 85cf). Much shallower, and I'm cold limited (even in a dry suit with dry gloves, I don't want to be in the water for more than an hour Nov-Apr). Not saying to get small cylinders, but "BIG FREEKIN" ones just don't add anything to the dives I'm currently doing. If you want to step up to tech, fine, get double 130s.

Why? Because I dive wet and go buggin and sometimes I stay down at the 50-60 foot range for almost an hour and a half per dive on my 120. I withstand the cold pretty well so 70-90 minutes is often no problem for me. Of course I only dive when the surface temp is over 50. I guess it depends on the person and a lot of other factors about how you're diving.

 

[Rainer]

Why? Because I dive wet and go buggin and sometimes I stay down at the 50-60 foot range for almost an hour and a half per dive on my 120. I withstand the cold pretty well so 70-90 minutes is often no problem for me. Of course I only dive when the surface temp is over 50. I guess it depends on the person and a lot of other factors about how you're diving.

You're deco diving for lobsters (90min at 55')? That's hardcore! Even with a SAC of 0.5, I'd use more than 120cf after 90min at 55'.

 

[TimK]

I bought a steel 100 and liked it so much I went back and bought a steel 130! Made the LDS very happy, although he keeps telling me the 130's brother is very lonesome in the dive shop all by itself. Last time I was there as I was leaving I thought I heard him yell something about double 130's and trimix being good for shore dives in the area.

Seriously though, I love my 100. The 130 is a big tank and you definately notice it. You won't really notice the difference in the 100 and like everyone has said, shed weight--I took 11 lbs off the weight belt going from Al to steel.

 

[Bretagus]

Awesome, thanks for all the responses! I'm gonna hit up PG either today or tomorrow. Hopefully I'll see some of you in the water this summer,
Brett

 

[matt_unique]

Three alum 80's.....double up two of them for boat or deco dives and use the third as your shore dive tank or deco gas. That's what I do...double alum 80's for boat/deco diving with alum 80 for deco gas (if diving Block Island sound with no access to Nitrox) or use my single alum 80 for winter shore dives.

You can do a lot of diving on twin 80's. For example, I do a 20 min deco dive on the Bass followed by a 20 min deco dive on the U853 with double 80's and surface with a good margin in back gas. I use EAN70 as my deco gas. I would have sufficient gas to complete dive #2 even with deco gas system failure. Obviously lost deco system on dive number 1 would not allow me to do dive number 2 following safety protocols.

Steels are nice...if I could choose I would get double HP steel 100's but the advantages are not worth the cost difference for me right now compared to doubled alum 80's.

--Matt

 

[ScubaSarus]

Well in that case Matt I would double 2 - 72 CF steels only due to bouyancy issues in colder waters as it would allow a lot of weight to be taken off the belt. Wouldnt be safe in warm water though. Old 72's can be had for $50 some places. Ide also make sure they were galvanised steel. The 72 CF fabers are tiny and love using mine for the Beavertail dives or any long walk to the entry.

I need to add one would need to get a special Hydro-Plus done on the tanks to fill them to 72 if the 72 cf included the overfill tanks usually get. Depends on the tanks as the new steels I hear can be overfilled or filled to top ratings (cf) for life.

 

[crlavoie]

I've had personal experience with steel 72s, AL80s, steel 100s and I have a buddy who used AL100s. Out of those cylinders, I'd recommend the HP steel 100s for boat dives or anything over 40fsw. I had never come even close to running out of gas...NDL chases me out first.

However, you might not want to rule out some slightly bigger tanks. I got a mild case of cylinder envy on a charter the other day. I thought I was manly lugging my steel 100s on the boat. That was until I helped the other four guys load their 108s, 120s, etc. on the boat. I felt a little inadequate. Don't worry, I just e-mailed my counselor.

All kidding aside, there are other sizes of tanks out there -- both HP and LP tanks -- which I have no experience with but do see on boats quite often. Hopefully, someone who owns one of those tank sizes will chime in. No matter what size you buy, I would highly recommend a steel tank in general due to factors already mentioned. Good luck.

LobstaMan

But wait, there's more! We have quite a collection of AL 80's as well.

For anyone that's interested, we're looking to unload a couple of the 108's. Between my brother and I, we currently have 14 tanks. Why? Well, maybe Jim can ask his therapist for me. I can't afford my own right now:huh: I've got hydros to pay for, you know?

 

[dave4868]

Basically, I'm deciding between an 80 or a 100. The Al80 suited me fine last season for shore diving... but its the chartered dives I'm unsure about. The 100 is ~$70 more, 5-6lbs heavier and a few inches longer. Weight is a concern as my female dive buddy was complaining about lugging an Al80, so the 100 would be even heavier (if only by a few pounds). The 100, however, would give an extra 10-15min BT in the 50-80ft range... but I'd only be diving to that depth once or twice a season (if that).

I'm partial to the PST (Pressed Steel) HP steels, using 120's most of the time, but occasionally using 100's.

Older, used PST HP steels were branded Sherwood/Genesis, US Divers, Dive Rite, and others. I don't know the current brands that might use them other than Pressed Steel themselves.

The 100's are nice because, compared to the al80, they're 2" shorter, about 3 lbs heavier empty, only about 5 lbs heavier full and have a nice 1.3 lbs negative buoyancy when empty versus 4.4 lbs positive for the empty al80.

Here's a nice tank specs chart from Huron Scuba Adventures, Inc:

http://www.huronscuba.com/equipment/scubaCylinderSpecification.html

Over the years, I've bought a bunch of used HP steels for myself and friends and for resale.

HP steel 100's turn up on the used market quite often, but they're very popular and sell fast.

Ballpark price has been about $150 to $200. (I just sold four of them last fall for about $200 each.)

Even though I use 120's mostly, I'm going to keep my last two 100's for now.... they really are a wonderfully compact tank with great buoyancy characteristics.

Being shorter, they may appeal to your gal, too.

Good luck.

Dave C

 

[LobstaMan]

Between my brother and I, we currently have 14 tanks.

Sounds familar....I've got a few, but nothing to compared to my brother. He's got almost a whole rental inventory of tanks.

Lobstaman

 

[Bretagus]

Just to update, I ended up not being able to decide, so I got two of each... X7-80 and X7-100. I'm pretty stoked... can't wait for them to arrive!