Why are the Shearwaters held in such HIGH REGARD?

[Dogbowl]

But also I take every opportunity to talk them up here and elsewhere, because I think that a company that puts such an emphasis on customer service, ongoing research and continual improvement of their products deserves to be well compensated. The only reason that great companies stay in business is if people support them. I'm doing what I can to make sure that they are around for a long time...

Curious...is Shearwater a private company? I'm guessing they are. When the Partridges retire for good, what would become of the company? I don't want them to change.

Every time I run across a fantastic business (I mean REALLY fantastic), I worry that it might get sold to new owners for whatever reason and you know what happens after that.

 

[_Ralph]

I think that the planners do not always match the computers as there is no specification for GF.

In another thread it became apparent that various members of this board believed that the GF Lo did not matter for a no stop dive. Part of the reason was that trying it they found that the value they set did not make a difference. Some examples were planners, some dive computers.

So the question arises, where in the dive does the change over between GF lo and GF hi happen? Starting at the bottom? Starting at the first stop? And if at the first stop what if there are no stops? Is the GF lo the limit at surfacing (the surface being the first stop) or is it GF hi (the surface being the last stop)?

So if I plan a 25% 30m 17 minute OC at GF 45/85 dive on a Petrel it is no stop. On Multideco it looks like this:

Decompression model: ZHL16-C + GF

DIVE PLAN
Surface interval = 5 day 0 hr 0 min.
Elevation = 0m
Conservatism = GF 45/85

Dec to 30m (1) Nitrox 25 30m/min descent.
Level 30m 16:00 (17) Nitrox 25 0.99 ppO2, 28m ead
Asc to 9m (19) Nitrox 25 -10m/min ascent.
Stop at 9m 0:54 (20) Nitrox 25 0.47 ppO2, 8m ead
Stop at 6m 1:00 (21) Nitrox 25 0.40 ppO2, 5m ead
Stop at 3m 1:00 (22) Nitrox 25 0.32 ppO2, 2m ead
Surface (22) Nitrox 25 -10m/min ascent.

which is consistent with 45% at 9m and 85% leaving the 3m stop.

I'll cover the user bit in another reply.

What is the ascent speed(s) in the Petrel?

I'm guessing it's going to be 3m/minute for shallow, which is what your MultiDeco schedule requests ....


_R

 

[lowviz]

...//... Every time I run across a fantastic business (I mean REALLY fantastic), I worry that it might get sold to new owners for whatever reason and you know what happens after that.

Shhhhh.

If they get too popular then J Outdoors will eat them too. Just enjoy it while it lasts and be happy with the here and now.

 

[PfcAJ]

I think that not understanding how a thing works and what the controls do is a problem. It is not the fault of the computer but a disadvantage of that computer as far as a user is concerned. If they don't properly understand the repercussions of the settings they may find themselves in difficult situations.

The existence of the extensive deep stop threads, talks at shows on how to choose GF numbers and questions in the wild from people owning these "what numbers should I use?" somewhat indicates that this is not well understood.

Well if you're trying to buy a zoop then you're going to be in for a surprise when you don't buy a zoop and get a petrel.

If you want a Jitterbug phone don't buy an iPhone.

 

[doctormike]

Curious...is Shearwater a private company? I'm guessing they are. When the Partridges retire for good, what would become of the company? I don't want them to change.

Every time I run across a fantastic business (I mean REALLY fantastic), I worry that it might get sold to new owners for whatever reason and you know what happens after that.

Yeah, that's a big issue in the world of rebreathers, where several of the well respected units are primarily the brain-child of a single person (like JJ, rEvo, and Meg). Mares just bought rEvo, so we will see what implications that has for the long term support of the company and it's products.

On the one hand, a big company means that the loss of one person doesn't mean the loss of the product line. It also means better access to capital, dealer networks and parts/service facilities. On the other hand, rebreathers represent a tiny product volume compared to stuff like OC regulators, fins, wetsuits etc.. So I can imagine a big company's CEO just deciding to drop the product if it wasn't helping their bottom line.

 

[DevonDiver]

I think that not understanding how a thing works and what the controls do is a problem. It is not the fault of the computer but a disadvantage of that computer as far as a user is concerned. If they don't properly understand the repercussions of the settings they may find themselves in difficult situations.

The existence of the extensive deep stop threads, talks at shows on how to choose GF numbers and questions in the wild from people owning these "what numbers should I use?" somewhat indicates that this is not well understood.

For tech diving, GF is pretty much a required knowledge nowadays. I spend a few hours covering this on my courses. If a tech instructor couldn't explain this succinctly to students, they have no business teaching at that level.

To be fair, Shearwater specifically refer users to read Baker's 'Understanding M-Values' in their manual.

Beyond that, a simple Google search for "Gradient Factors" reveals a plethora of good resources.

And, of course, there's 'Deco for Divers', which should be required reading for anyone buying deco tech with user-defineable parameters.

Maybe Shearwater should commission someone like Mark Powell to write their own GF summary to be included in the manual/box?

In all honesty though, it's just laziness that leads people to using GF without understanding the theory. There's plenty of accessible resources.... one only needs a barest shred of motivation to investigate them and educate themselves.

 

[Shearwater]

So if I plan a 25% 30m 17 minute OC at GF 45/85 dive on a Petrel it is no stop. On Multideco it looks like this:

Decompression model: ZHL16-C + GF

DIVE PLAN
Surface interval = 5 day 0 hr 0 min.
Elevation = 0m
Conservatism = GF 45/85

Dec to 30m (1) Nitrox 25 30m/min descent.
Level 30m 16:00 (17) Nitrox 25 0.99 ppO2, 28m ead
Asc to 9m (19) Nitrox 25 -10m/min ascent.
Stop at 9m 0:54 (20) Nitrox 25 0.47 ppO2, 8m ead
Stop at 6m 1:00 (21) Nitrox 25 0.40 ppO2, 5m ead
Stop at 3m 1:00 (22) Nitrox 25 0.32 ppO2, 2m ead
Surface (22) Nitrox 25 -10m/min ascent.

which is consistent with 45% at 9m and 85% leaving the 3m stop.

I'll cover the user bit in another reply.

This is a question that we get in tech support from time to time. This profile is a carefully crafted example that demonstrates the boundary point between real time and static decompression plans. To see the situation in a real time situation, you would need to change Multideco from a minimum 1 minute stop to a 1 second minimum stop. That will give you a profile with a 1 second stop and then two 19 second stops. The 18 seconds is the ascent time to the next stop. So basically you have created a profile with 3 one second stops. On a planner, this shows a three 1 minute stops. On a real time computer this would be a no stop dive.

As a side note, 30m/min is a pretty fast descent.

The Multideco plan and the Shearwater plan are fundamentally the same.

Bruce

 

[doctormike]

I am looking to get a new computer and was thinking about the Shearwaters. If they are not air integrated why are they so popular?

I think that the post above this one answers your question pretty well!

 

[Bratface]

My Perdix is the best computer I have owned, and I have owned several. It is the easiest to use of any I have owned and it is the most accurate. It uses AA batteries and the lithium battery has a very long life. They have excellent customer service and many video tutorials. Bluetooth to send your dive profile to your computer. You can also see your profile on the dive computer screen. You can change the dive number so that you don't have to start at 1, it can match the actual number of dive you have done. It only has two buttons and the menu is on the screen, no excessive scrolling and guessing. It can be programed for up to five gasses. It has a recreational mode as well as the technical mode. You can customize so many things. I'm not a fan of air integrated so this is not an issue for me. I also would like to have buckle straps instead of the clip but again, not an issue. You can always switch to shock cord. It's also very easy to install any software upgrades. The computer does all the work.

 

[nadwidny]

I think that not understanding how a thing works and what the controls do is a problem. It is not the fault of the computer but a disadvantage of that computer as far as a user is concerned. If they don't properly understand the repercussions of the settings they may find themselves in difficult situations.
.

Right. Because if people used something else (cough VPM cough) on a different computer it would be sooo much clearer.