Deco Cylinder for SM100 - What is your opinion?

[bubblejane]

I am going to purchase a deco cylinder for use with my SMS100. Currently, I mount 2 x 85cbf Faber cylinders and am unsure weather to go steel or aluminium for the deco cylinder??

Ideally - I would like to mount the deco cylinder behind my left tank and an aluminium 7ltr seems appealing because of the length, size and buoyancy characteristics. Although in complete honesty I am at a T-junction and am really unsure what deco cylinder to get.

Please could anyone with a similar set up please advise me of what works for them & why?

Thank you in advance

:diver:

 

[tphelps]

I am a tec diver that also uses the SMS100. All my tanks I use for tec are steel. As you probably know, maintaining buoyancy in tec is absolutely critical to make your deco stops. Of course, aluminum tanks become positively buoyant when they loss gas whereas steel cylinders do not. For this reason, I use steel cylinders in my tec configuration. Cheers

 

[voodoo36]

I dive the SMS-100 in sidemount configuration using 2 HP100's as my mains. When I add deco into the mix, I mount my 50% (AL 40 cu ft) under my left main, and another (if required) 100% (AL 40 cu ft) under my right main.

 

[NAM001]

IS NOT THE GENERAL PROTOCOL THAT DECO BOTTLES ARE TO BE AL'S? OPPS caps are gone. precisely for the bouyancy aspects of the tanks. little neg bouyancy from deco bottles.

 

[bubblejane]

Voodoo36 - Why did you choose aluminium over steel?

Tphelps - thank you for your response. You have certainly added a pro into the deco cylinder equation.

---------- Post added May 9th, 2013 at 12:43 AM ----------

Voodoo36 - Why did you choose aluminium over steel?​

 

[voodoo36]

Voodoo36 - Why did you choose aluminium over steel?

Tphelps - thank you for your response. You have certainly added a pro into the deco cylinder equation.

---------- Post added May 9th, 2013 at 12:43 AM ----------

Voodoo36 - Why did you choose aluminium over steel?​

Uh, oh....I see potential for debate here

.

My personal opinion for deco cylinders is that the aluminum tanks are a bit easier to rig and handle throughout the course of a dive. Steels start pretty negative and usually end slightly negative. Leaves them hanging a bit low and awkward for my liking. Al's start slightly negative and usually end slightly positive. By the middle of the dive these tanks have become a bit buoyant and fit nicely under my mains....making for a more comfortable dive. Also, if my dive calls for the removal and staging of the deco tanks (or passing them off to a buddy), the aluminum tanks are easier to manipulate under water than the steels. Again, all of what I say works well for me. Somebody else may believe the exact opposite and favor steel deco tanks for their own valid reasons.

 

[DevonDiver]

I don't want my deco cylinder/s being part of my core weighting strategy. For that reason - Aluminium. Not too heavy at the start, not too buoyant at the end. Can ditch/stage them at any time and cope with the relatively minor buoyancy shift using my core weighting and buoyancy capacity.

Steel stages belong with 90lb Donut wings... which belong in the stone age..

 

[tphelps]

I'm doubting myself now that I am "arguing" with a power player like Andy .

Here is a good video from Steve Martin, who has a lot more sidemount experience than I do. I found the last scene with the tanks relevant to what I was saying. Steel or Aluminium Cylinders..? (Steve Martin) - YouTube

I guess I should elaborate as to what kind of diving I do. I am a PADI Tec 50 diver and don't do any dives deeper than 50m. If I were a trimix diver, then I totally agree with Andy, I wouldnt want 6 steel cylinders, I'd sink like a rock! I have 2 Faber 50s (because I figured that would be the biggest I would need for deco at this current time and I got a good deal on them! ) In my tec dives in cold water, I use my drysuit with a nice thick undergarment so I don't need hardly any weight. And since Im not doing any wreck penetration at those depths, I dont need to stage any bottles. It depends on what kind of tec diving you do, your exposure suit, etc. For me, I haven't had a problem diving with my steels. I have done more tec dives when I travel to warmer waters so I usually rent the cylinders they have at the shop. In either case, I still do a buoyancy check the day before because of the new gear, water, etc. I've just noticed that it is easier for me to execute profile when I use steel. I have only been tec diving for a year so I do recommend listening to Andy and other experience tec divers. And if any said tec instructors have any constructive criticism for me, Im always open!

---------- Post added May 9th, 2013 at 03:00 AM ----------

Uh, oh....I see potential for debate here

.

My personal opinion for deco cylinders is that the aluminum tanks are a bit easier to rig and handle throughout the course of a dive. Steels start pretty negative and usually end slightly negative. Leaves them hanging a bit low and awkward for my liking. Al's start slightly negative and usually end slightly positive. By the middle of the dive these tanks have become a bit buoyant and fit nicely under my mains....making for a more comfortable dive. Also, if my dive calls for the removal and staging of the deco tanks (or passing them off to a buddy), the aluminum tanks are easier to manipulate under water than the steels. Again, all of what I say works well for me. Somebody else may believe the exact opposite and favor steel deco tanks for their own valid reasons.

Voodoo, I use steels for the exact reason why you don't haha. I mount my decos on top of my back gas (left lean, right rich obviously) so they sit nicely on top. I haven't really ventured to trying them underneath but I think its definitely worth playing around in the pool (because all of the cool kids go under ).

 

[bubblejane]

Thank you - it makes good sense.
I have been hiring aluminium cylinders and have rigged them the same as you describe in your response.
This sounds silly but do you still EAN test them every year? Do you think they require as much maintenance as steel cylinders?

The more I think about it - the more I would like aluminium.

 

[Jerry_]

Regarding EAN testing, stick at minimum to the local regulations for testing ( LDS might refuse to refill cylinders that don't comply), but in any case have regular tests done.