Tanks for a newbie

[ruready7]

I first dove with AL80 but then got a LP 108 (steel). Now I dive steel. Tank weights more but I take more weight off my belt so balances out. Steel is durable and as long as you keep moisture from getting inside so it will last for many years. Just my opinion.

 

[rstofer]

I have a couple of HP 100s. I bought them last summer and I keep them filled with Nitrox. Any time the opportunity arises, I am ready to go. With Nitrox, I will certainly run out of air before I hit the NDL.

The XScuba X7-100 weighs about 33# and the X8-130 weights about 43#. That is BEFORE adding air. Add 8# for the 100 and 10.4 for the 130. Do you really want to hump a 53# tank down the beach? The 130s may be excellent for boat dives.

Aluminum tanks are considered a writeoff when they are about 20 years old. There is no law or rule that makes this so but a lot of shops don't want to deal with old aluminum tanks.

Steel tanks, OTOH, are still in service after 50 years or more. Now, there is more experience with LP steel tanks than the newer HP tanks but there is no reason to believe their life expectancy will be remarkably less.

It is also nice to have your own tanks. Any time you want to go diving, just go. No messing around, no waiting on the LDS to open, just go!

I plan to get to a point where I have enough tanks for the 4 of us to do 2 dives without bothering with a refill. I would also like to get out of the Al 80 business. So, I need about 4 more tanks. An HP 100 weighs a little less than my Luxfer C80 Al tanks so it's a pretty good tradeoff. Besides the fact I can remove 6# from the weight harness.

Richard

 

[boulderjohn]

All the arguments in favor of the steel tanks are valid, but so is the advice that you may want to wait a while before making such a purchase.

You will probably want to buy two tanks rather than one. How often will you be planning a diving day/weekend that only includes one tank?

My own steel tank purchases only came after a lot of dives and after I had purchased the other equipment I used regularly.

Have you checked into the availability and comparative prices for rentals and fills? For example, I know shops where the difference in price between renting theirs and filling yours is pretty minimal.

Think through how often you are going to dive, where you will dive, what your options are, and then do a cost benefit analysis to see if it is worth while at this point in your life. If you decide it is worth it, then go ahead and make the purchase.

 

[rstofer]

So the question is: outside of the cost is there a downside to a newbie with a HP100?

Is there a downside to an HP 100? Maybe...

At the beginning of the dive, they are about 10# negative - 8# of it as air. You adjust your weights for the empty condition so you are definitely 7# or more heavy at the start of the dive.

Now, if you immediately go to depth and your wetsuit compresses, you lose that buoyancy and you are even heavier.

Perhaps you are using a SS backplate and maybe even backplate weights. These are non-ditchable.

So, you could find yourself on the bottom with a completely failed BC and a full tank. Even after ditching your weights, you still might not be able to swim yourself off the bottom depending on your equipment configuration. Backplate weights might be a really bad idea!

Over in the BC's subforum, you can find an Excel spreadsheet that deals with buoyancy. Fill in some typical values and see how much weight you will have to swim off the bottom even given that you have ditched your weightbelt. It would be cell F17 - cell H21; depth1 total minus Need lead.

I used:

Head weight = -10
Tank full = -10
Tank empty = -2
Suit = 24 and 8 {the suit is 24# positive at the surface and 8# positive at depth - a WILD guess}
BP = -8
Light = 0
Doubles = 0
Integrated = 0

This results in depth1.total = -24 and Need lead = -14. So, if I ditch my weights, I have to swim 10# off the bottom. Beats me... But if I had 8# of backplate weights and only 6# on my belt, I would have to swim 18# off the bottom. Gee, I kind of doubt it...

The problem is somewhat worse for the HP 130.

I have been deeply interested in this problem as I have HP 100s and I'm getting really old. I don't plan on doing any deep dives but if I ever do, one thing I will try is swimming off the bottom with an empty BC, full tank and no weights. Maybe I'll put a 20' tether on the weights and leave them on the bottom. This way when I go up a ways and after the wetsuit starts to expand, I will be able to stop the ascent.

I never consider by buddy to be my backup plan.

Richard

 

[gNats]

I have no idea how much rentals are in your neck of the woods but in Florida..... it's pretty cheap compared to ownership unless you dive aLOT. Also, when using a dive op or charter...... tanks (and weights) are usually included in the price of the trip (with an upcharge for enriched air.)

StormingHeavan - One thing you have to take into consideration is where you will be diving.

I am also in the Great Lakes, and dive quarries and will expand to the GL and the St. Clair River. While tank rentals at quarries can be had, the $7 fill is much cheaper than the cost of the daily rental AND the air fills. Most places I have reviewed require a rental fee and then air fees, including the first air fill. One quarry charges $20 for the rental, and $7 for each fill, including the first fill.

Plus, there are no air fills when you dive the river and many inland lakes that don't have a dive shop associated. I haven't done a charter, so I can't speak to the tank rental issue, but I do know on a charter I am booking, we are encouraged to bring a minimum to two tanks.

I am also a noob - less than 25 dives. I bought an AL80, which I am selling for two Steel 80s. I couldn't carry the 100s on my back.

I will probably up my total tank count to 4 Steel 80s, which is pretty pricey by summer 2011, just so I have the freedom of diving without stopping for an airfill.

Take a look at where you spend your time in the water... I think you will find in our Northern states if you dive more than 2 weekends a month, or you dive lesser traveled paths, the cost of ownership is worth it.

As to whether or not the Steel 100s are a good choice, I would definitely say get the tank you can afford and carry safely and comfortably. I bought the AL80 based on price and with little knowledge of tank differences. The AL80 overpowers my tiny frame however. I tried a Steel 80, and wish I would have used one of those before I made the AL80 purchase. Now I have to sell one and buy another.

Hope this helps.

 

[NudeDiver]

So, you could find yourself on the bottom with a completely failed BC and a full tank.

Would a lift bag solve this problem? If your BC has failed, but you still have air, put some in the lift bag - enough to get you moving at least. It might be a little faster than you like at some point - but if you could work its dump valve, you could keep it under control, and if nothing else, you could always let go after you've shallowed enough for your suit to give you what you need. Not ideal, but beats sitting on the bottom until your air runs out.

 

[boulderjohn]

I am also in the Great Lakes, and dive quarries and will expand to the GL and the St. Clair River. While tank rentals at quarries can be had, the $7 fill is much cheaper than the cost of the daily rental AND the air fills. Most places I have reviewed require a rental fee and then air fees, including the first air fill. One quarry charges $20 for the rental, and $7 for each fill, including the first fill.

Wow.

I've never been in that area, but that's more than I have paid elsewhere.

How long is the $20 good for? A day? A weekend? Can you easily use one rental tank and keep getting it refilled nearby, or are you going to have to rent more than one to get in a good dive day? (In one place I have dived, the one refill station takes a long time for refills, and you can have very prolonged surface intervals without a second tank.)

If you have these figures, it should not take too much advanced math to figure out how many dives you would have to do to break even on tank(s), valves, annual visual inspection, and hydro inspection every 5 years.

Then figure out a way to calculate the advantage of having familiar equipment you know and are comfortable with.

Whatever

 

[rstofer]

Would a lift bag solve this problem? If your BC has failed, but you still have air, put some in the lift bag - enough to get you moving at least. It might be a little faster than you like at some point - but if you could work its dump valve, you could keep it under control, and if nothing else, you could always let go after you've shallowed enough for your suit to give you what you need. Not ideal, but beats sitting on the bottom until your air runs out.

That's where I'm at. I bought a substantial SMB and a 100# lift bag (wanted 50# but it was out of stock). I am convinced a 30# wing is sufficient so a 50# bag will be more than adequate.

At the moment, I am not going deep enough to matter. Our family diving revolves around my grandson and he is limited to 40' by training and 30' by edict. A lot of these boundary conditions just aren't important right now.

Richard

 

[Puffer Fish]

That's where I'm at. I bought a substantial SMB and a 100# lift bag (wanted 50# but it was out of stock). I am convinced a 30# wing is sufficient so a 50# bag will be more than adequate.

At the moment, I am not going deep enough to matter. Our family diving revolves around my grandson and he is limited to 40' by training and 30' by edict. A lot of these boundary conditions just aren't important right now.

Richard

I have 100's, 117's and 133's...but the difference in the is only the weight of the air when full... when low, they are all about the same. Assuming that you are correctly weighted to be neutral at the safety stop...when the tank is low...the only amount you would have to swim up is the suit compression issue.

I have tried that from 100 ft in a 7mm with hooded vest...and it is not fun.. possible, but not fun... however, from 30 ft, it was reasonable. One option would be to send up the smb on a line and pull up the line...but riding up the first 60 or so is possible if you dump air as you go up... which was not that hard to do.

 

[NudeDiver]

I'd like to get tanks - but as several posters pointed out, just one isn't really going to do anything. I need at least two, to make it effective. Three would be more reasonable. Four would be required to give me a weekend of 2-tank diving. At $400+ each for steel tanks, that's $1600. A fair wad of cash. Rental cost on 4 tanks for a weekend is $40. Cost to fill up 4 tanks you own is $28. So, that means renting four tanks for a weekend cost $12. It would take over 130 weekend of 4-tank diving just to break even with the cost of buying 4 tanks. That's not even including the costs of maintenance or other issues.

So while, yes, if you buy tanks you get the size you want, while if you rent tanks (here) you'll be getting steel 80s, from a cost perspective, it doesn't even seem to be a close contest.