Scubapro octo question

[flyingvisit]

Ok so noob question alert time!
After some scratching of heads, pulling of hair out etc I think I've made my decision. I think I'm going to go the route of the Scubapro Mk17/G250V set up because although most of my diving has so far been in the US, I plan to dive in colder/dirtier UK waters.
Anyhow - when I look on the scubapro website, they only offer 2 dedicated "octo" 2nd stages - the R395 and the R295. However, I'm not sure what their performance is like - wouldn't I be better off with another G250V? If I chose to have that as my octo does it really matter about the fact its not brightly coloured? Can you get a coloured cover for it? Or just coloured hoses?? Sorry if its a stupid question!

 

[=C=]

Hello,

Nope, Color does not matter.

There are two options here:
1) adjustable reg $$$
2) non adjustable $

I have as my secondary a detuned non adjustable to prevent freeflows. The logic behind a more expensive adj reg is such: "In an emergency do you really want to be breathing on some cheap clone or a reg that is as good as your primary" FWIW I personally pass my primary and breathe off my secondary so my answer is I dont mind...

 

[Hank658]

Hello flyingvisit,

Another G250V would work as an octo. Your local reg tech should 'de-tune' it a bit. When it is set for a primary it is real easy to breathe. When used as an octo that same ease makes it prone to a free flow. De-tuning reduces the free flow tendency. Another option would be to see if you can get an S555. No adjustment knob, again your reg tech can set it for proper use as an octo. SP discontinued the S555 (at least in the US) so there might not be many around as new.
R295/395's work fine as octos. They are not the performers that either a 555 or 250V are but they will do the job. Many people use the same second stage for both primary and octo so you are in good company asking the question. AFAIK, neither the 555 or 250V can be swapped out for a yellow cover but a yellow hose can be put on any of the regs you mentioned. The key point would be that your buddy knows what your octo looks like and where it is located before you enter the water.

Hope this helps.

Hank

 

[c5diver]

i think the S555 and S600 can use the same purge cover and i know you can get the yellow purge cover for a S600. a nice yellow miflex hose and your set for an octo. i wonder if the adjustment valve can be removed from a s600 and capped like the s555 to make a simple detuned octo? i like the s600 look better.

 

[DA Aquamaster]

With the adjustable G250V or S600 do not detune them for octo use.

You can crank the adjustment knob in a couple turns (during the dive, not during storage) and you can set the flow vane at "min" and you will get more than enough resistance to freeflow for octo use. And then when you need it, you can still access the fullperformance of the regulator.

Detuning one will involve screwing the orifice in slightly farther. That increases spring pressure (but so does screwing in the adjustment knob) and will increase inhalation effort, but it also reduces the working range of the valve, reduces the maximum flow rate and decreases the effectiverness of the purge button. It also produces more wear on the seat during storage, so in the end by detuning you get no upsides and several downsides.

 

[rstofer]

If you wear your octo on a necklace and donate your primary (with a 5' hose, maybe), it doesn't matter what color the regs or hoses are. YOU are going to breathe from the octo and it is hanging right below your chin. You won't have a problem finding it.

Richard

 

[Hank658]

DA,

One of the main reasons I like something like a 555 for an octo is the lack of an adjustment knob. Divers I have seen are not necessarily disciplined enough to keep the knob set at a particular point and in an OOA situation it can be contribute to an already tense situation if the knob is cranked the wrong way. Maybe it's just me, but I kind of prefer to keep things simple regarding my octos. I use a 395 on my singles rig and a 555 on my doubles. Set them at 1.6/1.7 in the shop and they work fine with no messing around.

Since you are always right on track with your posts I would appreciate hearing your thoughts on this.

Hank

 

[Interceptor121]

Unless you are a rich man don't spend so much money on the octo because as a normal diver you will seldom have situation when you need to use it. Both Octopus will do the job the R395 has a VIVA control that the R295 does not have. I have the R295 and due to teaching I use it quite a bit, it is very robust and has not given me any issues so far.
Most importantly make sure you keep it clean and visual inspect it all the times you dive

 

[DA Aquamaster]

DA,

One of the main reasons I like something like a 555 for an octo is the lack of an adjustment knob. Divers I have seen are not necessarily disciplined enough to keep the knob set at a particular point and in an OOA situation it can be contribute to an already tense situation if the knob is cranked the wrong way. Maybe it's just me, but I kind of prefer to keep things simple regarding my octos. I use a 395 on my singles rig and a 555 on my doubles. Set them at 1.6/1.7 in the shop and they work fine with no messing around.

Since you are always right on track with your posts I would appreciate hearing your thoughts on this.

I dive with a pair of G250V's and I keep the backup on a bungee necklace with the adjustment knob screwed in about 1.5 to 2 turns. Both are tuned in the 1.0" of water range with the knob all the way out. With the knob on the back up turned in a bit, I have never had freeflow issues, yet it still breathes comparatively easily when I first switch to it, and when things settle down and if the situation allows I can turn the knob back out for lower inhalation effort and potentially less CO2 retention.

In the real world you will be the one using your octo. In technical diving everyone teaches donation of the long hose primary. Eventually once all the dinosaurs die, that will be the standard in recreational instruction as well. The reality is that it works so much better with no downsides and more accruately reflects what happens most of the time when a semi-panicked OOA diver goes visiting to borrow some gas. As it is, the odds are good that an OOA recreational diver will steal the primary and leave you on your octo.

In either case it is nice to have an octo that has the same performance as the primary. The S555 qualifies in this regard and with the flow vane set in the "min" position, it will not sustain a freeflow even if the purge button is bumped. I have never been overly impressed with the performance of R380/R390/R395 and preferred the large diaphragm of the R190, but at least they had an adjustable flow vane.

SP removed that feature from the current R295 - forcing people to upgrade to a more expensive balanced second stage to get the adjustabel flow vane - a feature that really only made sense on an octo. What it means is that the R295 would have to be significantly detuned to prevent freeflow or have a non adjustable flow vane fixed in the "min" position and both limit performance.

If I were diving an R395 as an octo, I'd adjust it to about 1.2" to 1.4" of water (max performance for many of them) and leave the flow vane in the min position, as I prefer a better breathing backup and I don't think unintentioanl freeflows are an issues when they are set up that way.

 

[Interceptor121]

The R295 on my regulator has done around 300 dives, from RIBs, shore, small and large boats and not gone into free flow once. It might be set to minimum but if you are at the stage of needing an octo your priority should be to ascend not to worry about performance?