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Post by nemrod on Oct 8, 2006 9:55:25 GMT -8
Well, in my next life then I will go Navy since it seems they wear their masks correctly. Mike would be proud. Thanks for those photos, very nice.
James
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Post by scubadiverbob on Oct 8, 2006 10:12:13 GMT -8
duckbill wrote: Thanks for the excellent information. If only my mask could talk! Then I could have had some company on my 2 3/4 hour solo river dive/snorkel earlier today. The neat thing is that I found an old 40+' sunken boat which appears to be wooden in construction, and several 1930s-40s cars, or what's left of them (such as the "aroogah" horn I found near one of them)!
Was that in the Feather River or Sacto. River? You got my interest up ... Maybe you could show me after I fix my SB-101 strobe and I'll get some pictures. PM me with some info.
Thanks, Robert
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Post by SeaRat on Oct 8, 2006 10:55:39 GMT -8
I love the photos... thanks a bunch for the smiles out here in Northern IL. Hey John, Do you think I could use a couple of the shots of you guys at the museum? I'd give you credit etc. for them and keep them copyrighted and whatever else we need to do. Those are super cool. Gayle Gayle, I have no problem with you using the photos, but I'm afraid that they are not the quality you would need for the museum. I could probably get higher quality scans if you would need, and I would like credit for them, as some will probably eventually make it into my book. Also, if anyone is interested, take a look at the "Official US Navy Photos" I posted on the last page. The Navy diver in the hatch at the bottom of the photo has twin tanks (probably the older aluminum) with a USD manifold, and he has his with the reserve mounted backwards. This is how I have mine, as it is impossible to accidentally trip in this position. It is on the right, and the reserve lever is pointed toward the diver's back, rather than out and away from the diver. The diver at the top of the photo has his manifold mounted in the normal configuration. The other photo of the UDT divers exiting the surf shows that these guys both also have the reversed configuration for their J-valves. This protects it from that inadvertent bump that could lead to tripping the reserve without the diver's knowing it. I have had that cronfiguration on my Sherwood manifold with a J-valve, and it has worked very well for me. Contrast that with the photos of the valves on the divers awaiting their turn to dive a few post earlier, and you can see that the J-valve lever sticks up and can easily be tripped. In the USAF, our jump tanks had a manifold guard on it to keep the parachute from tangling with the manifold, and we tapped over the whole area with masking tape, which also prevented this inadvertent tripping of the J-valve. John
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Post by pearldiver on Oct 11, 2006 12:03:29 GMT -8
Thanks John, I'll keep in touch. You know we're going rather slow till the cold weather sets in. Those are super cool photos. What an adventure you must have had!!
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Post by SeaRat on Oct 11, 2006 21:51:55 GMT -8
A yellow USD Equi-Rama mask and matching yellow snorkel just went on E-bay for $46.67. I bid on it early, and was going to again today but got caught up in other stuff at work and forgot about it. But that, with $7 for shipping, was a bit stiff for me anyway. So they are still out there. John
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Post by nemrod on Oct 11, 2006 23:24:23 GMT -8
Yes, but if you look close you will see that the skirt has ruffles along the top, still probably OK for some good diving but showing age.
James
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Post by SeaRat on Oct 12, 2006 4:13:32 GMT -8
Nemrod,
That's why I thought, for its condition, $46.67 was a bit much.
John
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YankDownUnder
Pro Diver
Broxton 'green label' Aqua Lung and 1954 USD Rene triple 44s.
Posts: 162
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Post by YankDownUnder on Oct 12, 2006 12:46:00 GMT -8
I'll let you know what it is like when it arrives.
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Post by SeaRat on Oct 12, 2006 16:58:03 GMT -8
I'll let you know what it is like when it arrives. I would too, but I didn't win the bid. I stopped at $15. I don't really need another mask, and I just picked up a like-new Scubapro oval mask and Shotgun snorkel (better than the one pictured) for $15 at the LDS. John
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Post by SeaRat on Oct 14, 2006 10:30:35 GMT -8
We've been discussing how great the comfort, warmth, and style is for the oval mask. So why did it go into disfavor? There are a couple of reasons. Here's a diagram put out by AMF Swimaster in 1973: Note the difference in the field of vision between the three-window mask and the oval mask. AMF Swimaster called it "tunnel vision" or a "visual tunnel port distant from eyes." Basically, they sold new masks based upon the increased field of view. Here's another study, which appeared in the publication Human Performance and Scuba Diving*[/B] in 1970: You can see from these that the field of view is limited with the oval mask. But the oval mask was easy to make, and therefore less expensive to market too. So they needed a different type of mask which overcame these problems. Scubapro, in 1976, showed us this catelog entry on masks: My favorite mask in the 1970s and 1980s was the Supervision Cat. No. 219, which did not have the large purge. When this mask was no longer available without the purge, and after my first mask melted off my face, I got a new one and changed out the front plate so that the purge was not there. I liked the vision better than the purge. John *Cy Yttri, Director of Publications, Human Performance and Scuba Diving*[/B], Proceedings of the Symposium on Underwater Physiology, Scripps Institution of Oceanography, La Jolla, California, April 10-11, 1970 page 8.
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Deleted
Deleted Member
Posts: 0
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Post by Deleted on Oct 14, 2006 11:49:59 GMT -8
John
You make a valid point with these diagrams. However, I remember the triviews as being heaver than a typical round mask. And the forward nose pocket, as you implied, blocked ones vision downward.
The early Pinochio solved some of the side vision problems and the later models, ie: the deluxe, had a wide lens which really helped......but the nose pocket still blocked my downward view. And the thing is heavy.
I had a Tekna tri view that was nice and light, but the side windows didn't help for anything save let light in.
The newer designs today with nose pockets and lens closer to ones face create what I call the dead vision zone between the eyes.
I gave my son a new production model of the old Pinochio, which is pretty light in weight for black rubber and he preferes it to his low volume up close to the face with corrective lens modern cats eyes mask........again due to the dead vision zone.
I have for the past 15 years been using a wide oval (more wide than oval) that is translucent green silicon. Plate glass window style with nose pockets in the bottom..........best vision and weight balance I have found.........
One other point I'd like to make......when I first started diving back in 67......my YMCA instructor lectured us about how fighter pilots had to always keep turning their heads to watch for the boggymen who could sneak up on them......he drilled into our heads to do the same thing while under water. This was in part to be aware of ones surrounding and in part due to the narrow vision of our round/oval dive masks. I think that would be good advise to anyone, even today.
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Post by SeaRat on Oct 14, 2006 13:32:30 GMT -8
Mossback, Your point on checking by turning your head is very good info; we did that in our scanning techniques when searching from USAF aircraft. It has to do also with the best sensing areas of the retina of our eyes. Right in the center, there is an area called the fovia. It is the area of the eye that has the greatest density of light-sensing cells (cones and rods). Here is a reference to the anatomy of the eye: en.wikipedia.org/wiki/Retina#Physical_structure_of_human_retinaThe fovia is where we get our clearest vision, which is important in dim light and poor visibility when diving. It is also right at the center of the eye, as is seen in this diagram: en.wikipedia.org/wiki/FoveaSo having the "tunnel vision" is not a great handicap if the diver works at observing, turns his/her head often, and pays attention. I did like my Scubapro mask, though, and this is what it looked like in the 1970s: John
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Post by nemrod on Oct 14, 2006 17:42:00 GMT -8
I hate completely every tri vue mask I have ever used and as to the diagrams they are just that--diagrams. I don't think ovals and other more traditional masks are that restrictive in field of view. There is a mask out from gag--Tusa--gag---gag that is actually quite nice. Crystal clear silicone with a square lens. It has a very unobstructed forward field of view compared to other modern low volume masks like the Mares X Vision which I also use and find somewhat bothersome actually--but--it has bifocals so I endure. Nemrod
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Post by standingupinf on Oct 14, 2006 19:47:49 GMT -8
I also cast my vote for the round (mike nelson) style mask. You could keep a little water in the mask after clearing and use it to clean up fog with just a little shake. The purge valve is to me a waste of vision space. Not needed and obstructs vision. I was taught the reason for not putting a mask on your head was this would damage the rubber skirt and eventually the mask wouldn't seal properly around your face. As far as the tri view masks are concerned they were an interesting idea however mine was heavy ,awkward, and I really couldn't see anything thru the side lights. As far as turning our heads we were also taught to swim up doing 360 degree circles watching out for boats etc. This turned out to be good advice, since in the Chicago area boaters were prone to using a divers flag as a target and enjoyed running the flag over and watching it pop up again.
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Post by SeaRat on Oct 14, 2006 20:48:28 GMT -8
...As far as turning our heads we were also taught to swim up doing 360 degree circles watching out for boats etc. This turned out to be good advice, since in the Chicago area boaters were prone to using a divers flag as a target and enjoyed running the flag over and watching it pop up again. Now I have to tell this story from the Salem Aqua Club in the 1960s. We had a diver, whom I remember as Virginia, who was diving in Yaquina Bay, Oregon when she heard a boat zip past her dive float. It too was using the flag as a target for high speed manouvers. But it made a mistake. It came around a second time, and Virginia had surfaced and watched it come by. Not only did she watch it, but she got the numbers of the boat off its bow is it made its turn around her float. She memorized the numbers and the boat's details, then swam in with her buddy. In the afternoon, they found the boat at the boat dock. They had looked it up, and found out where it was moored. That night, they made a night dive. That's right, they made a night dive under the dock, and Virginia had her spear gun. From what I was told (we were members of the Salem Junior Aqua Club at the time), she launched a spear up through the bottom of the boat, then swam back to their exit site away from that spot, and never came back. Apparently, they did not sink the boat, but left the spear in the hole in the boat. Anyway, it's a good story (real or not) and gave us some comic releif at the behavior of sometimes insane boaters. John
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