Weighting question.

[MaxE]

I have a question about weighting or rather adjusting weighting. How much weight can I ditch when switching from an AL 80 tank to a PST HP steal 80 tank (PST E7-80)? 4lbs?
As always thanks in advance.

 

[RJP]

Sounds about right in general, but to really dial it in you'll need to know which specific HP steel tanks you're talking about.

Here's a chart that may be useful...

http://www.indianvalleyscuba.com/se...ction/information/CYLINDER SPECIFICATIONS.pdf

 

[MaxE]

I meant to add that info and have edited the original post.

 

[tbone1004]

PST e7-80 is -2.5lbs when empty per the chart, Luxfer 80's are +4.4, Catalina 80's are +4. So depending on which aluminum tank it is, you can drop 6.5 or 7lbs

 

[decompression]

Minor point, when looking at the chart see if it's weight is with or without valve.....


Sent from my iPhone using Tapatalk

 

[boulderjohn]

PST e7-80 is -2.5lbs when empty per the chart, Luxfer 80's are +4.4, Catalina 80's are +4. So depending on which aluminum tank it is, you can drop 6.5 or 7lbs

Just to make it clear, tbone1004 is comparing the buoyancy of the tanks, not the weight of the tanks. The buoyancy takes into consideration the differing sizes of the tanks, which is important. If you just compared the weights of the tanks, you would not get the information you need.

 

[Malibugary]

Might be a dumb question but specs state sea water. Would the tank bouancy differ in fresh water as in heavier?

 

[boulderjohn]

Might be a dumb question but specs state sea water. Would the tank bouancy differ in fresh water as in heavier?

Yes, they will be less buoyant in fresh water.

 

[Malibugary]

Ok now I'm confused. Less in freshwater?

 

[boulderjohn]

Ok now I'm confused. Less in freshwater?

Less buoyant, not less weight. A tank that is less buoyant buoyant in fresh water will appear to be heavier than it appears to be in salt water, even though it weighs the same.

An object is neutrally buoyant when it weighs the same as that volume of the water it is in. Salt water weighs 64 pounds per cubic foot. If you have a tank that is one cubic foot in size, and it weighs 63 pounds, it will float in salt water because it is lighter than the water it displaces. Fresh water weighs 62.4 pounds per cubic foot. That same tank will sink in fresh water because it is heavier than the water it displaces.