Al40 vs lp50

[Asheron]

I think this isn't really an apples to apples comparison, there are tiny Steel 40s that are better than alu 40s from a weight comparison

HP Steel 40 14.8 lbs - 1.48lbs = 13.32# Not too expensive, $184 much lighter and shorter.

The LP50 holds 25% more than an AL40 and that a worst case. The #/CF is better on an LP50 so it is a more efficient form to carry gas, but its wasted weight if you simply don't need it.

If lightweight and 40CF are your requirements, Steel HP40 is the winner.

Hmm, let me clarify. The two AL40 combined together with a Lola valve will get me through both my dives without having to swap tanks like I have to do with the Horizon. So the AL40 do meet my dive needs and I have them laying around so I won't have to buy a set when my buddy asks for his LP50s back.

I was just confused originally to find the LP50 were so much heavier and still went positive when empty and 2anted confirmation of that.

 

[Cio]

Except that HP40s are:
1) less likely to be fully filled
2) too short to sidemount as bailout (<18”)
3) have nearly no resale value

Well, Well, aren't you a wet noodle, I thought this was about weight?

#1 So? these are for rebreather backup, he won't be filling them for every dive or on random boats and its not like there is an overabundance of 3K compressors out there hindering proper HP fills. I would think a rebreather diver can find 3.5K fills or maybe has their own booster.
#2 So? I have no side mount experience but if weight is an issue I can't imagine it is impossible to go in a pool and figure out how to make this work with some adjustments. Not saying this should be done as a standard but people have special requirements and sometimes alternate configurations can be made to work to suit those requirements, don't be so uncreative.
#3 Is this supposed to be funny? What are we buying here? Last I checked the resale everything SCUBA is not all that great. Besides, are we going to let resale value drive decision making on life support equipment?

 

[grantctobin]

Well, Well, aren't you a wet noodle, I thought this was about weight?

#1 So? these are for rebreather backup, he won't be filling them for every dive or on random boats and its not like there is an overabundance of 3K compressors out there hindering proper HP fills. I would think a rebreather diver can find 3.5K fills or maybe has their own booster.
#2 So? I have no side mount experience but if weight is an issue I can't imagine it is impossible to go in a pool and figure out how to make this work with some adjustments. Not saying this should be done as a standard but people have special requirements and sometimes alternate configurations can be made to work to suit those requirements, don't be so uncreative.
#3 Is this supposed to be funny? What are we buying here? Last I checked the resale everything SCUBA is not all that great. Besides, are we going to let resale value drive decision making on life support equipment?

I'm not sure if you missed that this is for an SCR or not. He will likely be filling them on every or every other dive. While there are a few shops in NJ and a ton in FL, the likelihood of these cylinders being filled to 3442psi when cooled is quite low.

The height and weight distribution associated with these cylinders makes it extraordinarily unlikely he will ever get them to behave in trim. On his back, they will be SUPER ass light and require a tail weight. They're too short to be able to gear up appropriately on a boat (they're 3 inches shorter than an HP80). If sidemounted, they're short enough that he'll be limited in his options for clipping points.

As to 3, when he does indeed try and sell these, he'll realize they trade for ~$100/cylinder on average. A steel cylinder will likely depreciate by 10-20%.

To conclude, they're trash cylinders with very little functional purpose.

 

[Cio]

Hmm, let me clarify. The two AL40 combined together with a Lola valve will get me through both my dives without having to swap tanks like I have to do with the Horizon. So the AL40 do meet my dive needs and I have them laying around so I won't have to buy a set when my buddy asks for his LP50s back.

I was just confused originally to find the LP50 were so much heavier and still went positive when empty and 2anted confirmation of that.

Gotcha, it is best to look at it from a cubic foot per lb. , then it makes sense. (the more the better) LP 50 is better if you need 50 CF if you need 40, it is over weight. You can see below, the HP40 is the most efficient carrier with the most CF per pound, that said, ALU tanks are just easier and you already own them. Basically, ALU tanks are the least efficient storage on a weight basis, LP steel is better but only marginally (overfilling can help this) and HP steel is by far the best.

LP50
18.9lb + 1.24lb = 20.14lb of total weight for neutral
This is 2.48 cu ft per pound

Luxfer SO40
14.9lb + 2.4lb = 17.3lb
This is 2.31 cu ft per pound
Metal Impact AL40
15.3lb + 1.4lb = 16.7lb
This is 2.39 cu ft per pound
Catalina S40
16.2lb + 1.4lb = 17.6lb
This is 2.27 cu ft per pound

HP Steel 40 14.8 lbs - 1.48lbs = 13.32#
This is 2.70 cu ft per pound

 

[Cio]

I'm not sure if you missed that this is for an SCR or not. He will likely be filling them on every or every other dive. While there are a few shops in NJ and a ton in FL, the likelihood of these cylinders being filled to 3442psi when cooled is quite low.

The height and weight distribution associated with these cylinders makes it extraordinarily unlikely he will ever get them to behave in trim. On his back, they will be SUPER ass light and require a tail weight. They're too short to be able to gear up appropriately on a boat (they're 3 inches shorter than an HP80). If sidemounted, they're short enough that he'll be limited in his options for clipping points.

As to 3, when he does indeed try and sell these, he'll realize they trade for ~$100/cylinder on average. A steel cylinder will likely depreciate by 10-20%.

To conclude, they're trash cylinders with very little functional purpose.

I stand corrected, SCR will make that different.

I also consider money spent on this type of stuff as gone as soon as its spent, probably not a bad idea to buy things that are in demand.

As far as trash cylinders, that makes me sad to hear, all cylinders matter, I'd double them up!

 

[broncobowsher]

I'll just put this out there...
This is the first I have heard of the Mares Horizon in the actual wild and not part of a PR campaign.