Not the same SS vs Aluminum question

[lexvil]

@lexvil , reading through my response made my think of a question that I’m surprised I hadn’t thought of before. Is the M series either top or butt heavy? At -14.7 pounds of buoyancy it would seem that either one might cause what I’m experiencing. I may be completely wrong, and I won’t be able to verify it for awhile due to the cold weather, but now I’m curious.

I’m not sure what you mean by “m” series, is this a pst tank? Or asahi?

 

[RIHappyDiver]

Most of us are more comfortable with weight on our backs than on a belt. I wonder if there's something about your current BCs harness system that is causing the discomfort in that position.

I suspect this will go away when using the wide webbing that is standard with a backplate harness. FWIW, I haven't had any comfort issues swimming on my back with a steel backplate, standard harness, and tanks varying from an AL80 to an HP120. Is there any way you can try one out before you buy?

You might be absolutely right, but I have no way to verify it. The BC is a Litehawk, so it has the 2” webbing with a bit of a hip pad. I’m using Hog weight pockets that are positioned a bit more forward and 4 pounds of the listed weight is trim. It makes sense that the SS plate would be the best way to go, and that what I’m experiencing is just an oddity.

 

[lowwall]

You might be absolutely right, but I have no way to verify it. The BC is a Litehawk, so it has the 2” webbing with a bit of a hip pad. I’m using Hog weight pockets that are positioned a bit more forward and 4 pounds of the listed weight is trim. It makes sense that the SS plate would be the best way to go, and that what I’m experiencing is just an oddity.

That doesn't look like 2" webbing to me except on the waist band. More like 1" with a nylon sleeve on the upper part. There's plenty of potential pressure points from the chest strap to the various plastic clips.

I can't tell you how much more free I felt when I got rid of all that stuff by switching to a BP and basic aka hogarthian harness.

 

[RIHappyDiver]

I’m not sure what you mean by “m” series, is this a pst tank? Or asahi?

It’s a Faber. They make (made?) 2 HP100s, the standard HP100 (-0.59# empty buoyancy, -8.41# full buoyancy) and the M100VB (-6.69# empty buoyancy, and -14.11# full buoyancy). In contrast, the Faber LP85 is 0# empty buoyancy and -6.7# full buoyancy. Now, as to why I purchased this tank knowing it was a heavier tank, well, HP100 in hydro for $150 used seemed too good to pass on. And, all-in-all, it has been a good tank.

 

[RIHappyDiver]

I'm wondering if it is simply a weight issue. I'm not familiar with those tanks but for example my double lp50's weigh more than a single 100 but need more lead. So although you are compensating for the weight difference your 100 weighs more, perhaps more than 6 pounds more than the 85.

Your actual combined weight is therefore more with the 100. When swimming on your back all the weight is facing down the direction of gravity, therefore you feel it more.

Or maybe it's just me over analyzing physics.

I had never thought of it in those terms, so it made me curious. Turns out the dry weight when suited up is about 2# difference, with the 100 being the heavier. Could this do it? Maybe.

 

[lexvil]

It’s a Faber. They make (made?) 2 HP100s, the standard HP100 (-0.59# empty buoyancy, -8.41# full buoyancy) and the M100VB (-6.69# empty buoyancy, and -14.11# full buoyancy). In contrast, the Faber LP85 is 0# empty buoyancy and -6.7# full buoyancy. Now, as to why I purchased this tank knowing it was a heavier tank, well, HP100 in hydro for $150 used seemed too good to pass on. And, all-in-all, it has been a good tank.

I guess I haven’t encountered one of these but I would buy it at that price too. Can you find someone to borrow a bp/w from? I think you may find it more comfortable while diving and likely on the swim too, stainless would be my choice, aluminum is fine if you can dig up a great price over stainless than do that.

 

[RIHappyDiver]

I guess I haven’t encountered one of these but I would buy it at that price too. Can you find someone to borrow a bp/w from? I think you may find it more comfortable while diving and likely on the swim too, stainless would be my choice, aluminum is fine if you can dig up a great price over stainless than do that.

I think you are all right in that I should rent/ borrow a bp/w from. It’s not like I’m planning on purchasing right away. Thanks for the input everyone.

Erik

 

[stuartv]

The bottom line is that an AL plate is 3 - 4# lighter (generally) than an equivalent SS plate.

You're diving with 16 or more # of lead on. Get the SS plate. It will let you ditch 3 - 4# more lead from your rig than an AL plate will allow.

 

[GJC]

I only use an AL plate for tropical 80 degree water because I don't need lead weight with it and steel would be too heavy. I use a steel plate for 5 mil or drysuit because I can carry less lead.

With BPW, you can position weight on the upper or lower can bands in weight pouches as well as on the waist strap or on a weight belt. So you have a lot of options to position weight to make it most comfortable for you.

 

[Zef]

This started about the question of which plate material you should buy. My suggestion given your issues is to get the aluminum plate...it will not contribute physically or psychologically to the issues you are experiencing, and when you figure things out you can always purchase a steel plate later on. An aluminum plate is versatile for both local diving and travel diving, a steel plate too but slightly less so due to its weight for air travel.

A plate setup will be different than your bcd setup and you will most likely find yourself needing a few pounds less lead overall regardless of plate material due to the lack of padding in the unit, and less propensity for trapped air conpared to a jacket/vest bcd.

I am sure you will figure things out once you set up and start diving a bp/w regardless of the plate material, but in ypur present case aluminum is probably the way to go.

-Z