Sherwood Oasis/Blizzard and the never ending Piston vs Diaphram

[diver69]

Hi rescue,

Could you elaborate your caution on use in salt water? And also, what you're saying then is the Blizzard comes with moisture retention fins as well? As I have said, that's really important to me. I think I mentioned earlier that my mouth got so dry during a dive in the Philippines last year that I had to swirl salt water in my mouth during a dive so my tonguw wouldn't stick to the top of my mouth.

Appreciate any input.

 

[rescuediver009]

Hi rescue,

Could you elaborate your caution on use in salt water? And also, what you're saying then is the Blizzard comes with moisture retention fins as well? As I have said, that's really important to me. I think I mentioned earlier that my mouth got so dry during a dive in the Philippines last year that I had to swirl salt water in my mouth during a dive so my tonguw wouldn't stick to the top of my mouth.

Appreciate any input.

Okay, I don't want to step on anyone's toes (sherwoodtech) but here it goes. The blizzard has the heat sink, which is those ridges on the outside. Also it has the moisture rentention fins inside the second stage. This is what you are looking for as they help moisten your breath. Again I say help. Some people say that it doesn't make a difference. They are only supposed to help and I think that sherwood tech can vouch for that.
As for my caution in salt water. Once I saw a sherwood first stage that was corroded beyond anything on the inside. It was because the salt had crystalized around the bleeder valve, and didn't allow it to seal. So next time it was in the water, it let water in instead of letting the air out. Then of course the person didn't know that there was water inside and it started to corrode. Again, this is not something wrong with the reg. The bleeder is actually an awesome thing. I used my blizzard in salt water, and as long as you maitain you equipment proprely by rinsing enough, you will never have anything to worry about.
One final thing is the exhaust tee. It is awesome because it keeps the bubbles out no matter what.

 

[truva]

Just to pick up on the second part of the original post.
Except for low-end rental equipment that needs to be serviced often and easily I cannot find a good reason for piston style regulators to still be manufactured. Was this originally designed to get around a patent or something?

Truva

 

[SubMariner]

As for my caution in salt water. Once I saw a sherwood first stage that was corroded beyond anything on the inside. It was because the salt had crystalized around the bleeder valve, and didn't allow it to seal. So next time it was in the water, it let water in instead of letting the air out. Then of course the person didn't know that there was water inside and it started to corrode. Again, this is not something wrong with the reg. The bleeder is actually an awesome thing. I used my blizzard in salt water, and as long as you maitain you equipment proprely by rinsing enough, you will never have anything to worry about.
One final thing is the exhaust tee. It is awesome because it keeps the bubbles out no matter what.

The part about mtce is key. ANY reg will not perform well if not properly maintained & serviced. I bought my Sherwood Blizzard new in 1991. It has been in salt & fresh water & lots in between. AAMOF we spent 2 years on a sailboat in the Bahamas and I was using it as my primary reg.

Well, I bought a new reg in 2001 (Mares Abyss). Howver, my Sherwood gets used at least twice a year by my sister-in-law or some other family member on trips. This year it will be Cayman for 10 days. I would not hesitate to use it if my primary developed a problem, it still performs that well.

If it fills your needs, go buy it. It's a workhorse that won't let you down.

 

[rescuediver009]

i would have to agree that any reg needs maintenance. As for the pistons being obsolete, it is like saying why do they make manual cars when they have automatic transmission.?

 

[truva]

i would have to agree that any reg needs maintenance. As for the pistons being obsolete, it is like saying why do they make manual cars when they have automatic transmission.?

I never said they were obsolete; they have been making diaphragm regulators long before the piston style. With the design problems that the piston has, I just wanted to know why they made them in the first place. Was this not a patent issue or was it just a solution to a nonexistent problem?

Truva

 

[DA Aquamaster]

Just to pick up on the second part of the original post.
Except for low-end rental equipment that needs to be serviced often and easily I cannot find a good reason for piston style regulators to still be manufactured. Was this originally designed to get around a patent or something?

A piston reg is on average much simpler and more reliable -very nice traits in life support equipment. A good balanced piston first stage is also virtually always capable of higher airflow and faster response than a balanced diaphragm first stage.

A diaphragm first stage makes environmental sealing for cold water use easier, but other than that I am hard pressed to think of a reason to make diaphragm first stages. And yes, patent issues were involved as SP had a lock on the flow through piston design and other companies turned to balanced diaphragm designs to try to compete. A balanced diaphragm first stage can utilize a larger orifice than an unbalanced diaphragm first stage and is capable of higher flow rates, but still nothing close to the flow rate that can be achieved with a flow through piston first stage.

 

[iflyprops]

I have the Brut for an octo...won't do that again. It breathes hard on the surface! Isn't the standard oct just a brut with a high vis cover on it?

 

[Katz]

Blizzard is $220 and Maximus is $275 now at LP. It's quite a big drop for Maximus ($100) and $80 for Blizzard.

 

[truva]

A piston reg is on average much simpler and more reliable -very nice traits in life support equipment. A good balanced piston first stage is also virtually always capable of higher airflow and faster response than a balanced diaphragm first stage.

A diaphragm first stage makes environmental sealing for cold water use easier, but other than that I am hard pressed to think of a reason to make diaphragm first stages. And yes, patent issues were involved as SP had a lock on the flow through piston design and other companies turned to balanced diaphragm designs to try to compete. A balanced diaphragm first stage can utilize a larger orifice than an unbalanced diaphragm first stage and is capable of higher flow rates, but still nothing close to the flow rate that can be achieved with a flow through piston first stage.

I will agree that they are probably capable of higher flow rates, but at what point does this become over kill? I expect we are there already. Anyway I thought that SP was the new guy on the block so to speak and didn’t want to do what everyone else was doing which were the diaphragm regulators that were probably adapted from industry and modified. I just cannot go along that the piston style is more reliable, they have a very significant problem that I don’t think they have addressed yet, that being the raw water/crap contact with a dynamic sealing surface, until they can fix this, I will argue that the diaphragms are the more reliable style.

DA you brought my attention to a design that really is horrible that being the unbalanced piston style in another thread.

Anyway this debate as been beaten over and over again here…..

Truva