Tank/weighting conundrum

[halocline]

I did one dive with an AL100 and that was enough. Big, bulky, heavy, and floaty. I wouldn't even think about getting one of those. The faber FX100 is a nice tank; I just bought one for diving the FGB and I like it quite a bit. I use an AL plate, no lead, in a 3 mil and I'm still a touch negative. It's no big deal being a pound or two heavy. Get the tank you want, and either find a used AL plate or try the hammerhead AL plate; I think they're around $50.

 

[sschlesi]

Also, I've never had a Faber tank that didn't rust within the first three years.

How many Faber tanks have you had?

 

[TSandM]

I really think the best solution, for this very new diver, is to stay with the Al80 and some ditchable weight, until he has more experience and can make good decisions about diving somewhat overweighted.

I dove HP100s with a steel backplate and no weight at all in Cozumel, but I had several hundred dives at that point, and knew I was extremely unlikely to end up in a situation where I was at the surface and completely stressed out, and unable to achieve postive buoyancy. I also dive as part of a very competent and attentive team. That's really different from having a dozen or so dives and diving with who knows what kind of buddies.

 

[Puffer Fish]

How many Faber tanks have you had?

Don't mean to hijack the thread, but older Fabers (which look just like the current ones) had a rust problem. It was due to the steel they were using and using zinc phosphate as a pretreatment under the powder coating. The new tanks are Chromomoly steel and an actual zinc coating under that powder coating. Huge difference. They also make a lot of different tanks...so telling one from another is difficult. They have a very floaty 80 cubic ft steel... that weighs in at around 25 lbs, but is 8 lbs positive when empty. Been considering making a set of warm water doubles from them.

I use 100 cubic ft Faber FX tanks for beach dives, but I understand the desire to have more bottom time.

I would switch the plate, as doing so removes some weight, and makes the rig neutral.

 

[DA Aquamaster]

I really think the best solution, for this very new diver, is to stay with the Al80 and some ditchable weight, until he has more experience and can make good decisions about diving somewhat overweighted.

That's a pretty conservative viewpoint. If the OP goes with an AL plate he will subtract 4 pounds of negative buoyancy, even if he then "loses" 6 pounds of positive buoyancy switching to an X7-100 or FX100, the net difference is only 2 pounds more negative buoyancy than he has with an AL 80 - plus another pound or so in swing weight.

He is comparatively new to diving, but it is a relative thing and unlike most recently certified divers, he seems to have the weight thing figured out. And per his profile he is both AOW certified and has at least 25 dives, taking him out of the raw newby category. I'd worry a lot less about him being 2 lbs overweighted than I would about the average OW diver sent forth into the world 10 or more pounds overweighted from their OW class.

I also don't see where more experience with an AL 80 in the same configuration will improve his ability to make better decisions. How much vanilla ice cream does one need to eat before he or she is ready to try chocolate?

One thing that may help might be to do a dive or two with 2 pounds of lead on a weight belt or in a pocket, where it could be ditched if the extra 2 pounds causes a problem. That would provide the experience of being 2 pounds more heavily weighted without the "risk" that seems to be assumed to come with the larger steel tank.

 

[rstofer]

Maybe my system of thinking is wrong here but isn't the main idea to 1) be weighted so that you are neutral at 15 ft with 500 psi in the tank and 2) be weighted so you can swim to the surface without any lift from a wing. I know there are other considerations but aren't these the most important? If not , I have to start rethinking this thing.

I'm not sure about swimming up with a -10.5# tank, a -6# plate and a -2# regulator. If you lose most, or all, of your wetsuit buoyancy due to compression, getting 20# off the bottom might be a stretch. Lift bags and SMBs come to mind. But I don't think you are going to swim it up.

I'm also not certain that even with an Al tank you can get to a situation where you are buoyant at the surface. But a SS plate makes it a certainty that you will be negative (warm water, thin wetsuit). Better to use an Al plate (or Kydex) and carry the weight on a ditchable belt/harness. Integrated weights are also a possibility in warm water.

In south-east Asia, I dove with just a Lycra skin. I carried 6# of weight on a belt and used an Al 80. If I dropped the belt, I would be, at most, about 3# negative. If my BCD worked at all, I would be ok. Otherwise I would have to ditch the rig. Then too, the BCD was probably a little floaty.

In Monterey with a 7/8mm wetsuit, getting positive at the surface is no problem. I can easily ditch 20# of lead. However, I still have the problem of swimming up some yet to be determined weight off the bottom even with no ballast.

Richard

 

[TSandM]

DAA, I was really trying to avoid the idea of him having to buy a new plate. I agree that switching to an Al plate makes the two rigs almost comparable.

 

[Puffer Fish]

DAA, I was really trying to avoid the idea of him having to buy a new plate. I agree that switching to an Al plate makes the two rigs almost comparable.

Without a lot of work, found an Aluminum backplate for $45..would seem to be a reasonable investment.

 

[DA Aquamaster]

Offshore, I often do 2 tank recreational boat trips with a single set of doubles. In NC, that means a 3mm wet suit and essentially an overweighted condition. Losing all the lift in a wing is a remote possibility unless you do something extreme like pull the elbow out of the BC or pull the inflator hose off the elbow.

But just to be prudent I have a lift bag bungeed to the bottom of the plate and in the rare case that the wing would fail, and I would not be able to swim the rig up (cramp, etc) it could be used for redundant floatation. A diver can shoot the bag from the bottom with a reel or finger spool and in effect "climb" the line. Alternatively, if the bag has a dump valve, the diver can use the bag as a BC during the ascent. You can clip the bag to the scooter ring and ascend vertically and use the pull cord to dump excess gas as you ascend. It helps to stay just a bit negative on the way up and slow way down as you approach the safety/deco stop so that you can get neutral at the stop without passing theough the stop depth. If you opt for this method you want to practice as it is not as easy as climibing an upline.

 

[MaxBottomtime]

How many Faber tanks have you had?

Four 95s, two 80s.