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Post by SeaRat on Sept 23, 2014 17:01:12 GMT -8
Jaybird, I always worry about these things from my parachute jumping days. Here's a bit of the text from my manuscript, Between Air and Water, the Memoir of a USAF Pararescueman about one of our first jumps at Ft. Benning, Georgia during our initial parachute training: This fall I hope to finalize this manuscript, and get it to publishable form. Here's a photo of an Army soldier at Ft. Benning during our Jump School, practicing jumps off a three-foot platform. Note the two leg straps, held together with a cross-band between the legs. Now look at that and thing what would happen if the left leg strap went to the right side, and vice-versa. With a crotch strap on a Dacor Nautilus, there is only one strap, but it goes right down the middle of the crotch--same type of problem. John
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Post by diverdon on Sept 23, 2014 17:04:14 GMT -8
I haven't tried a giant stride with the Nautilus, just a seated entry. I would hesitate to attempt one with a crotch strap for exactly the reason you mention. Looking at my gopro footage I believe I may have had the tank a little high anyway so I'll try it a little lower Friday. Should be fun.
Don
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Post by nikeajax on Sept 23, 2014 17:52:44 GMT -8
Ughgh, John, that made me jump when I read it--NASTY! My wife sells AT (assistive technology), and every once in a while she goes to conferences with veterans who have TBI (traumatic brain injury). They're finding out more and more about TBI, especially about how young kids are affected by concussion, I've had a fractured skull twice as a small child: I'm not really sure what it did to me either! I can't help but wonder if with today's battlefield-medicine that lieutenant could have survived, kept alive, and whether or not that would have been a good thing?
Jaybird
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Post by SeaRat on Sept 23, 2014 18:24:21 GMT -8
Jaybird, I just posted a photo of the jump equipment we had during that time. Note that the helmet was a standard issue U.S. Army helmet, with a standard suspension. It really does not absorb much shock when subjected to that kind of a hit. In the USAF, we had different jump helmets which were more like motorcycle helmets. Time Magazine just ran a feature article on " The Tragic Risks of American Football," 1 which describes TBIs very well. A skull fracture does not necessarily lead to TBI, but the two can co-exist. Concerning the lieutenant, he suffered a massive skull fracture with subsequent, underlying bleeding that caused rapid death after hitting the ground on his heels, and going straight over to his head. The news reported that he landed in a plowed field, but it was actually a baked clay field that probably was plowed sometime before WWII. This is much the same as the high school football player that Time used in its cover story, and it is doubtful that any emergency measure could have saved him. Don, I look forward to your dive Friday with the Nautilus. The shoulder straps need to be tight, but not so tight as to inhibit movement (see my post on my earlier dive a few weeks ago). Weather cooperating, I hope to dive my Nautilus in the next week or so with the new weights. John 1PS: I just realized that this is available only by subscription, and so found a Time, Inc., video which explains the problem very well, and is readily available over the internet. Titled, This is your brain on football, the video explains the long-term problems associated with TBI and football. In the 1980s, when my kids were looking at sports, I told them they could play any sport except football. I was worried about permanent knee injuries at the time. They choose competitive swimming.
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Post by diverdon on Sept 27, 2014 6:37:25 GMT -8
I got to dive the Nautilus twice yesterday and took my Gopro. It is kind of cumbersome getting into the thing with 7mm farmer johns, hood and thick gloves, but once at depth I found it works fairly well. I set my buoyancy at roughly 30', then took it to 65' on both dives. I found it easy to control at depth but near the surface it wanted to ascend faster then I liked, especially on the second dive as my aluminum 80 was fairly buoyant at the end of the dive. It takes several minutes to swap out tanks on the Nautilus so I just used one tank for both dives making my 3rd dive of the day rather short. My first dive I used my DA and a steel 72. Anyway I'll load a couple quick vids (1 loaded, 1 later) if anyone cares to watch them. I had no time to add fancy music or edit them for length, but the visibility is really good at Fortune pond so maybe you'll enjoy them. In the first video I shot a second diver going on her way and she wasn't a "buddy" as I was pretty much diving solo though there were other divers in the area. You could see a steady stream of bubbles coming from my inflator hose fitting. I'll address that later as it could use a new o-ring I'm sure. The second shows me ascending in the water column and a steady stream of bubbles coming from the Nautilus which is venting as it should. *More later-gotta dive* Don
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Post by SeaRat on Sept 27, 2014 14:32:56 GMT -8
Don,
Very nice video of the Nautilus CVS. Now we have two diving the Dacor Nautilus CVS in open water. I was able to see both videos by clicking on the image above, then on the back button at the Photobucket website. It looks like the CVS was venting as you ascended in the first video I was able to see, just as it is supposed to do.
I have an opportunity to dive mine early next week, but may not be able to do so as last week after our vacation to the National Parks, I developed a cold/sinus infection that is still "draining." Hopefully, it will resolve shortly, but until it does I'm grounded.
John
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Post by diverdon on Sept 27, 2014 16:07:14 GMT -8
Ever get the feeling you're being watched? Here is a video that Eben took of me with the Nautilus. I must say its hard to look interesting and not swim away. You'll see my bad acting in the following link. You'll also see a steady stream of bubbles coming from my lp inflator fitting. I'll replace the o-rings eventually. But its just only a slight nuisance. I must say, this Nautilus is a fun piece of vintage dive gear. *More later* Don
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Post by diverdon on Sept 27, 2014 16:18:20 GMT -8
Don, Very nice video of the Nautilus CVS. Now we have two diving the Dacor Nautilus CVS in open water. I was able to see both videos by clicking on the image above, then on the back button at the Photobucket website. It looks like the CVS was venting as you ascended in the first video I was able to see, just as it is supposed to do. I have an opportunity to dive mine early next week, but may not be able to do so as last week after our vacation to the National Parks, I developed a cold/sinus infection that is still "draining." Hopefully, it will resolve shortly, but until it does I'm grounded. John I'm glad you were able to see both videos. Both Eben and I could hear the Nautilus working today. It kind of grunts when it adds air as I descend. I'm pleased to say that the Nautilus appears to be working as designed and the fitting should be a minor fix. I hope you feel better soon, John. I developed a similar head cold/congestion early this week and had a lot of trouble equalizing. I ended up with nose bleeds on each dive, but the five dives I was able to do were pleasurable.
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Post by SeaRat on Sept 27, 2014 17:16:05 GMT -8
Don, I've looked at all your videos now, and enjoy seeing someone else who can appreciate the engineering that went into the Nautilus CVS by Dacor. It moves through the water very easily, and has a whole cubic foot of air buoyancy capacity ( 62.4 pounds, or one cubic foot, in fresh water [28.3 kg]; 64 pounds in salt water). One aspect that is not easily realized until a few dives on the unit is that the baffles tent to compartmentalize the water in certain areas. So if you assume a head-up position, the water will stay in the bottom of the unit. However, if you go level for say thirty seconds, the water will equalize throughout the unit via the baffles, and it will be easier thereafter to maintain a level position. The same is true of head-down positions; it takes a bit of time for the water to route itself through the baffles to attain a specific position's stability. You mentioned the problem of removing the cylinder from the Nautilus CVS. That has to do with the retention system on that earlier model; later models had a cam-action retention system that made it much easier to get the cylinder out. You can convert yours, easily, by picking up a compatible Dacor backpack and taking the stainless strap off it and putting it onto your Nautilus CVS. Here you can see my other Nautilus CVS with the cam-action release for the cylinder: Concerning my cold/sinus infection, it's draining now, and I hope to test it out on Tuesday in the pool. If I can get down to 18 feet in the pool snorkeling, then on Wednesday I'll try out the Nautilus again. If not, I'll give it another week. It's not good to dive with sinus problems, although like you I have done it in the past without suffering long-term problems. But I was young then. I have this concept of using my Dacor Nautilus CVS with my canoe, going to a really nice lake and putting the canoe into the water. I'll then float the Nautilus CVS behind the canoe, get to where I want to dive, jump out of the canoe with my float, tie the canoe to the float and untie the Nautilus CVS, flood the Nautilus CVS to vertical, climb into the harness, dive the unit, surface and reverse the process, then paddle the canoe back to the dock, trailing the Dacor Nautilus CVS behind at the end of the dive. That may enhance my solo diving capabilities, as the unit floats quite nicely. Hopefully, sometime this fall... John
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Post by Seahuntjerry on Sept 27, 2014 19:33:37 GMT -8
Hi Don and Searat, yes it was cool seeing the Natilus and his owner. I deer crashed into me on the way to Fortune pond took out drivers window and side mirror.Don and his friend Jim rigged up a short term 50 mile shrink wrap till it got warmer today. Say those Dacor weights are cool,glad I got to see Don again this weekend. Jerry
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Post by diverdon on Sept 28, 2014 13:43:26 GMT -8
John, I'd love to see a cut-away of the Nautilus so we could get a better glimps of the compartments. But I only have one and its too nice to offer up as a sacrifice though I've heard there are those out there with two or more ... I may just have to swap out the tank strap for a stainless or even velcro bands as I intend to dive this more. One of the fellow divers at the pond this weekend thought it was a rebreather, though I don't know how much exposure he's had and didn't talk to him directly. I like too the idea of hauling it along in a canoe for harder to reach dive spots. That gives me a couple ideas, thanks. I do not have a canoe but we do have several kayaks which is close enough I suspect. Jerry did have an epic adventure this weekend getting to Fortune pond. It seems some big white tail deer set his sights on Jerry's van and just about took him out along with his window. At 50 degrees and 60 mph I'm sure the last 150 miles were brutal with no rear view or drivers side window. Sorry to drag you up here just to experience that. At least the diving was good as well as the company. It was nice finally meeting Eben and his wife along with Mr. and Mrs. Swimjim. There were several others who came along but I suppose I should save that all for the other thread. Don
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Post by SeaRat on Sept 28, 2014 19:52:02 GMT -8
Don, I have two Nautilus CVSs, but one is not here right now. Even so, I don't think I'll sacrifice it. Somewhere there is a set of Dacor slides or PowerPoints that show the cutaway of the Nautilus CVS, as it is referenced in that instructor's manual. I looked on-line, but could find no reference to it, so it apparently has never been scanned. I did find a United Divers of NH newsletter which talks about a demo of the Dacor Nautilus CVS in September of 1979. Jerry, I hear you about the deer; when we were at Bryce Canyon National Park a week ago, we decided to drive part of it from the various overlooks. At one point, my wife, Chris offered me part of a pear while I was driving. I said, "No, with my luck I'd be in the middle of a bite and a bull elk would jump out in front of me." Not two minutes later, while Chris was in the middle of a bite, a four-point buck deer jumped out of the brush and right in front of our rental car. I had to hit the brakes hard, and Chris didn't see it until I hit the brakes. It was really wild, and then we started laughing after we remembered what I had just said about the elk. I'm glad you were not hurt in your deer encounter. John
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Post by surflung on Sept 29, 2014 9:17:57 GMT -8
DiverDon... CVS Master Diver!- I dove with Don on his 2nd and 3rd dives while he was using his Dacor Constant Volume System (CVS) BCD and it was kind of neat to watch him accelerate up the learning curve. He seemed to be handling it effortlessly by the 3rd dive. It becomes a lot easier to see how the thing works when you can watch someone actually diving with it. - The water intake is on the bottom. The air vent is on the top. And the demand regulator looks kind of like a push button on the BCD filler hose. Aside from a leaky quick disconnector, the system seemed to be working perfectly. On the 3rd dive, I could hear it making a kind of grunting sound as it maintained it's constant air volume. - I can see where getting into and out of the water takes some practice... That's a huge volume of water weight carried within the hard sided CVS... But it looked like Don had it licked pretty well after the third dive. After we surfaced, I could tell he had vented the water pretty quick because I looked over at him and he was bobbing on the surface with his head about 1.5 feet out of water! - It was quite a valuable experience to see the Dacor CVS in action... And diving with my new friend Don wasn't half bad either.
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Post by SeaRat on Sept 29, 2014 16:13:18 GMT -8
Surflung,
One thing to remember is that you cannot displace water in the Nautilus CVS unless the bottom water inlet valve is open. You can pressurize the unit, and it will leak air through the overpressure relief valve, but it won't change the buoyancy characteristics without the lower water inlet valve (which also serves as a water outlet valve) open.
John
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Post by nikeajax on Sept 29, 2014 18:15:02 GMT -8
So, what gives punk? Why ain'cha usin' yer 'Lympic fer that fine piece a machinery: you tryin' ta get the Dacor gods mad at'cha? Looks swell buddy! Jaybird
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