Question Halcyon aluminium versus carbon BP

[andrethediver]

Hi everybody, flying back from several weeks in Indonesia and thought I would seek advice. I dive Halcyon Eclipse AL BP/wing with standard AL STA setup with 18 lb Oxycheq wing instead of 30lb that came with the system. I dive exclusively in tropical waters, around 82-86F or so for the most part. Typically wear no wetsuit- a rash guard or Shark Skin top and cargo neoprene shorts. With my BC setup I need no weight and typically overweight by a few lbs with 12l tanks and more like 6 lb if I go with 15l heavier tank which I prefer (drop down like a rock with air out). Obviously I use way more air than I normally would. Other than gaining weight or wearing neoprene suit, I am considering going to Carbon Fiber backplate and perhaps STA as well in attempt to become more neutral. Are there other options I should consider? Thanks.

 

[Zef]

The only thing a carbon fiber backplate (and STA) will do is make your wallet more positively buoyant due to the air that fills the void where your cash would otherwise be. There is relatively little to gain by using carbon backplate vs an aluminum one.

The Halcyon carbon fiber backplate weighs 1.2lbs , and the Halcyon aluminum backplate weighs 1.7lbs....the half a pound difference is rather nominal and you can save over $100 with the aluminum plate and achieve similar results to diving with the carbon one if you just take a big dump before your dive.

Seriously though, your air consumption and buoyancy would bennefit more from you spending your money on gaining more experience by diving more, instead of on gimmicky expensive equipment.

-Z

 

[andrethediver]

Yes, I dive plenty but mostly overweighted - no neoprene. After reading again on Eclipse system, i wonder if what I thought what was aluminum STA is one of these heavier convertible ones because it came with a 6lb block that I don’t use.

 

[Zef]

With my BC setup I need no weight and typically overweight by a few lbs with 12l tanks and more like 6 lb if I go with 15l heavier tank which I prefer (drop down like a rock with air out).

Are you stating that, despite the fact that you do not need any added weight, you still add some to be overweighted?

or

Are you stating that the weight/mass of your tanks is such that you are overweighted, without any other added weight, due to your lack of need to use neoprene and relatively lean body mass?

It is difficult to interpret what your itent is from what you wrote...please clarify.


Regarding STAs....I have been diving a BP/W setup for a number of years and have never had the need to use an STA. I have never had an issue with how my tank sits on the spine of my backplate, and it has never rolled or moved the slightest bit out of position once I have cammed down the pair of tank straps....my wife has had the exact same experience. We both use Dive Rite Voyager wings and neither has built-in "roll control". If you are looking to remove unnecessary weight from your rig to make it less negatively buoyant, the easy answer is to remove the STA regardless of whether it is aluminum, steel, or any other such metal.

-Z

 

[andrethediver]

Weight/mass of 12 and 15l standard aluminum tanks is such that my setup with me strapped in is very negative - at least unless I am wearing 5mm full suit. 3mm is a little better but still too heavy.

Halcyon aluminum backplate has no ability to pass cam bands through the plate - hence bolted STA is used for that. I am wondering if weighted STA that came with system isn’t a standard Aluminum one. I guess I will have to weight it. This seems like the one that came with.

 

[DiveTucson]

Halcyon does not make an Aluminum STA. So you most likely have a stainless STA.

 

[Zef]

Weight/mass of 12 and 15l standard aluminum tanks is such that my setup with me strapped in is very negative - at least unless I am wearing 5mm full suit. 3mm is a little better but still too heavy.

Halcyon aluminum backplate has no ability to pass cam bands through the plate - hence bolted STA is used for that. I am wondering if weighted STA that came with system isn’t a standard Aluminum one. I guess I will have to weight it. This seems like the one that came with.

Thank you for clarifying.

Here is a thread that discusses the buoyancy characteristics of a Halcyon carbon fiber plate:

Halcyon Carbon Plate

All else being equal, an aluminum plate and a carbon plate (and a tungsten plate, and a stainless plate, and a uranium plate) will displace identical amounts of water. Displacement is purely based on volume of the object being submerged - mass and/or density have no impact on it. (Edited to add...

scubaboard.com

Given everything you have shared, even though a carbon fiber plate may be slightly less negatively buoyant than an aluminum one, it is not enough to have a material affect on your total buoyancy while diving without any neoprene....you will still be overweighted. Due to this, I still contend that it would be better to keep the weight in your wallet.

-Z

 

[Endler's]

Halcyon aluminum backplate has no ability to pass cam bands through the plate

All modern Halcyon plates have tank band slots. (Only the "Traveler" wings have slots.)

FYI: Halcyon phased out the "Pro" carbon plates with molded in tank stabilizers. The new plates have just the "Cinch" molded in and are intended to be used with their carbon fiber STA.

 

[Barefoot_Lawyer]

I am surprised nobody has told OP to ditch the steel STA for a Carbon STA. $150 and drops 6 pounds from his rig.

EDIT: the weight I listed includes the removable weight, otherwise the differential is only 1 pound. But on a cost per pound basis, $150 for 1 pound is a lot better than $500 for 0.5 pounds.

 

[Zef]

I am surprised nobody has told OP to ditch the steel STA for a Carbon STA. $150 and drops 6 pounds from his rig.

Pretty sure the 6lbs is only if the removable weight plate is used with the STA...otherwise the STA with hardware should be about 2 pounds.

-Z