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Post by SeaRat on Jul 15, 2007 16:18:37 GMT -8
I now have four more dives on the Dacor Nautilus Constant Volume System, two with modern-style regulators (I hasitate to say "single hose regulator" anymore, as most now have a minimum of three or four hoses), and two with double hose regulators. These were all successful dives, as I took off the home-made regulator and went with a simple inflator system on the Nautilus CVS. I have a few interesting observations:
--The CVS is that, in that you can add air at depth, and as you surface the volume does not change. When you get to a certain pressure inside the system, it vents out the top. At first, it is kinda disconcerting to hear that thing (the top valve) pop off, but then you get to expect it after a while.
--The Nautilus takes significantly longer to submerge than does a conventional system, as all the air must be dumped and displaced with water before diving. This takes about 30 seconds for me.
--The Nautilus will float a double hose regulator out of the water, either right-side up or upside down. There was no flee-flow problem usually associated with the double hose regulator when I took off the system and let it float in the water (or put it there to get into it). Likewise, when on my back, it is very hard to get the double hose regulator to free-flow, as the Nautilus floats me higher than any comparible system (50 pounds of buoyancy under your back).
--Underwater, the double hose regulator is not in the regular position, but almost behind my head. It is several inches further away from my back, and this should make the inhalation resistance harder. However, this can be overcome in two ways. By swimming head-down, the regulator effectively becomes at the same horizontal plane as the lungs, precisely becouse it is further up and away from the head. Or, the diver (me) can swim on his/her side to ensure that the regulator is in line horizontally with the lungs. I used only two regulators, the Trieste II and my Sportsways Hydro Twin. Both are balanced regulators, with downstream valves, and very easy breathing. I have the venturi set on both regulators so that once the breath is initiated, no further breathing effort is required. My Hydro-Twin actually had too good a venturi, and with USD hose/mouthpiece system would shoot air out the exhaust, wasting air. I went back to the Healthways regulator (it has a plastic divider in the mouthpiece), with the inhalation side intake mushroom valve/cage removed. I used a knife years ago, and completely cleared out one Healthways mouthpiece of the cages on both sides--I used only one of these this time, as I felt that with the water displacement, the exhalation side would not be a problem (it would be almost sucked out, which it was). The hoses have to be much longer, as there is another 3 inches or so on each side that needs to be accounted for away from the diver. I used Nemrod Snark III hoses with the Healthways mouthpiece today.
--Once the unit is snugged up on the diver, it is fairly streamlined in the water. But it is not as nice as i single tank.
--With the unit inflated, swimming on you back can be accomplished against quite a current, as you are not in the water, but over it, more like a boat with legs. Likewise, my double hose regulator will not free flow except in an extreme layout position when I'm on my back using the Nautilus.
--You have to pump out the water before you can exit, or face carrying an extreme weight up to the shore.
--Modern regulator's hoses are too short for use with this system, as again it is further away from the diver's back.
Well, that about sums up what I've learned with this system so far. Five dives now, and I'll keep diving it.
John
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Post by SeaRat on Jul 16, 2007 18:17:05 GMT -8
I had Linda move this topic into the Vintage Diving Instruction and Technique forum as we are through buying and selling the Dacor Nautilus CVS, and I'm now exploring how it works (or doesn't work) in different diving situations. As stated above, ithe Dacor Nautilus CVS really does have some advantages with double hose regulators. What I did not mention too prominently though is that whatever regulator is used, especially in the double hose realm, it needs a LP port. So we are somewhat limited to the USD (Aquamaster, RAM, Pheonix, etc.), the AMF Trieste, and the Sportsways Hydro Twin and Duel Air.
John
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Post by diverdown1955 on Jul 18, 2007 10:22:47 GMT -8
JOHN, I HAVE A TECHNICAL MANUAL ON THE DACOR CVS. WOULD YOU LIKE ME TOO SEND YOU A COPY? THIS THING IS VERY WELL THOUGHT OUT. THE SUCCESSFUL OPERATION OF THIS UNIT IS DEPENDENT ON HAVING THE ORIGINAL PILOT REGULATOR. JERRY POWELL HELPED ME WITH SOME HOSE PROBLEMS WHEN I GOT MINE. IT IS A BLAST TO USE AND TURNS YOU INTO A SUB COMMANDER / DIVER WHEN YOU USE IT. MY ONLY NEGATIVE THOUGHT IS HAVING TO HOLD THE PILOT REGULATOR AND HOSE IN MY LEFT HAND MOST OF THE TIME. I AM STILL LEARNING THIS UNIT AND WITH FAMILIARITY THERE MAY COME A GREATER DEGREE OF FLEXIBILITY.
JERRY diverdown1955
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Post by SeaRat on Jul 30, 2007 5:00:50 GMT -8
I put my Dacor Nautilus CVS into the water again on Saturday, and this time I got a few photos of it. I brought along my Nikonos II underwater camera, and took some photos of myself underwater, while a kayaker who was home on leave from the US Armed Forces Reserves took the topside photos of me. I had put the regulator back on the CVS system, as I had read the manual again, and understood the problems I had with the buoyant ascent on my first open water dive was of my own doing. I had not closed the water inlet valve, which allowed the unit to continue to fill with air. I decided to test whether the use of the water inlet valve would allow me to use the regulator without problems. Well, I was able to use the unit, but my regulator is too sensitive for much further use, and it leaks air. So while the dive was successful, I'm probably going to take it off for further use, and use only the power inflator that came with the unit. I'm also going to look for a Dacor auto/manual buoyancy control regulator for this unit, as the person who originally used the unit apparently replaced it with a regular inflator. I also put six pounds of weight into the weight slots (two small three-pound weights that fit). The unit is designed to take four 4-pound weights in the slots, for a total of 16 pounds. I used a wooden spacer to keep the weights towand the bottom, which probably is not the ideal place for them (toward the top would better balance the unit). Here's the photos I took, or had taken, of me with the unit: Here you can see that my Sportsways Hydro Twin regulator fits well on the system, but rides quite a bit higher than it would with regular doubles or even a single tank system. I have determined that this is not as bad as I at first thought, as I can vary my body position to a more head-down position and get a fairly good position for the regulator in relationship to my lungs. You can see that it is easy to use this sytem in the water. And, there is nothing on my front (I had to figure out a new way of carrying my car keys, inside the key pocket on my wet suit). With the Nautilus fully inflated, it has 60 pounds of buoyancy (one cubic foot, in fresh water, is 62.4 pounds, minus the weight of the unit and tank), and with the 6 pounds of weight that's 54 pounds. I also wore a 9 pound weight belt (I was in the wet suit tops only), for a total buoyancy of around 45 pounds. With that kind of buoyancy, I could get quite far on my back before there was any free flow of the double hose regulator. I swam upstream on my back quite successfully. On one of my earlier dives, I swam in the current on my back, and was able to cross the current easily with all that buoyancy. Without me in the Nautilus, the system floats quite high, and the regulator does not free flow. I took two self-portraits underwater (should have taken more). Unfortunately, the focus was a bit off, and I had a water leak in the Nikonos II (through the bottom--O-ring problem). The leak was not serious, and because it was fresh water, I just got a little spotting on the film. Here is what I looked like from the front. I was using a Scubapro oval mask, and my bicycle helmet with a light and snorkel attached. I dove my UDS-1 on a second dive with my Para-Sea BC, and actually like it better in the water than the Nautilus, but that combination does not have the buoyancy that the Nautilus CVS does. Jerry, thanks for the offer of the Technical Manual for the Nautilus CVS. I have the Instruction Manual, and if that is not the same as the Technical Manual, I would be interested. But I think that these are the same, as this is a multi-page manual on the Nautilus CVS. If anyone knows where I can get a Auto/Manual Buoyancy Control Regulator for the Nautilus CVS, I would be very interested in it. My home-made system does not work well, and I have replaced it with the normal inflator. But this invalidates some of the Nautilus concept. John
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Post by SeaRat on Aug 4, 2007 20:23:34 GMT -8
I now have two more dives with the Dacor Nautilus CVS, this time with a regular inflator hose system on it. The Nautilus CVS BC works very well in the water. Today, I had twelve pounds of weights in the weight channel, and that actually balanced the system even better. With that, I also had two four-pound weights on a belt. That was a bit heavy (12+8=20 pounds weight total), as I was only using half my wet suit (it's August, you know, with much warmer water), but I could not feel it at all, as all the excess weight was simply balanced by the buoyancy of the Nautilus. For the first dive, I dove my Hydro Twin double hose regulator. While it is possible to do this (I now have three double-hose dives on the Nautilus), I will not now recommend it. You need longer hoses, and Dan's expanding hoses work will with this system. I have just invested in a set of Dan's hoses (see: www.vintagescubasupply.com/hoses.htmlThese are the SDSH hoses. I was using them with a newer Healthways mouthpiece. I originally did not like that mouthpiece, but found when I dove the Nautilus system, I could put one of the nylon mushroom valve housings in with the mushroom, and the other (intake) was one which I had carved all the mushroom valve stuffout of, so it was smooth for inhalation. With the Nautilus, there was no problem with exhalation (as the water pressure helped that out a lot). After overcoming the inhalation cracking resistance, the Hydro Twin provides through its venturi all the air you need. So this was acceptable with the Hydro Twin (using the Healthways mouthpiece). However, there is a definite "hit" from the difference in water pressure between the regulator and the diver's (my) lungs. In some positions, this can be a full foot of water pressure difference, which makes for very negative water pressure breathing. I did compensate by swimming head-down, and the weights in the weight channel (above my lungs) helped maintain this position effortlessly. But that was not always possible, and after about twenty minutes I could feel the effects (stomach acid--for some reason, with me there is a correlation). I surfaced, went to the rocks, and got out of the water. I then took off the Nautilus with my steel 72 in it. I had to take the tank boot off to ensue that the weight channel was open for dumping the weights. Because I was using the Hydro Twin, the tank was high in the Nautilus, and that did not leave enough room at the bottom for the water inlet valve control handle to clear the ground, so I had to be very careful as to how I put the system down on the rocks. I took off the Hydro Twin, walked up to the road where my car was, and exchanged it for my Scubapro AIR-1 regulator. Upon getting down, I had a hard time getting back into the system on the rocks, and when I finally did, simply jumped off the rocks into the water without my fins. Floating on the surface, I put on my fins, then commensed flooding the Nautilus and diving. I had changed the shoulder strap of the Nautilus before the second dive, and found I had loosened it instead of tightened it. I ignored this for a while, then began enjoying the dive. With a multiple hose regulator (formerly known as a "single hose" regulator), the second dive was a joy. I was able to chase some fish, stay perfectly balanced in the water, and simply enjoy being weightless on the dive. I swam against the current, and had no difficulty in spite of the bulk of the Nautilus, as it does't "catch" the water much. I then continued downstream, and continued to observe fish. I saw several northern pike minnows about a foot or longer, a dead salmon (spawned out), and a number of juvinile fish. Toward the end of the dive, I surfaced, took the Nautilus off in the water after blowing out the ballast tank, and adjusted the strap again, this time the correct way (it has a metal webbing holder that keeps the webbing from moving on the harness). I then flooded it again, until it was upright, and slid into the harness easily (why hadn't I done that on the rocks?). With the harness adjusted so that the unit was snug, it swam even better. I was getting low on air, and so surfaced for the last time, blew the water out of the Nautilus, took my fins off, and climbed the shore rocks out of the Clackamas River. I had found a bracelet made of shells upstream, where people jump off the cliffs, and had put it on my wrist. Now, I noticed it again. It was a good hike back up to the car, but I had a very good two dives, and learned a lot more about the Nautilus CVS today. I will be diving the Hydro Twin again soon, but when I do, it will be equipped with the Hope-Page Mouthpiece system and not the newer Healthways mouthpiece. That is a better system, as it has wider openings for inhalation and exhalation, and can be balanced by the diver during the dive if needs be using the aluminum screw rings to reposition the hoses in rotation with the mouthpiece for comfort. John
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Post by SeaRat on Nov 15, 2007 6:56:28 GMT -8
I received my second Dacor Nautilus this month, and last Saturday took it out on a dive. I really did enjoy it, and the diving in the Clackamas River was great. It was full wet suit time, as the water temp was in the 40s, but the visibility was about 20 feet. The river was low, and so it was ideal for taking the Nautilus out in open water.
I wanted another Nautilus as I did not have the full functionality on the last one. It did not have the Dacor regulator on it, but this one does. So now I have the entire rig, and wanted to test it in the water. I put 12 pounds of weights into the weight chute, so that took some off my weight belt (which is good).
I walked down to my usual entry spot, put on my fins, mask and helmet, then my gloves, and entered the water beside a rock I use for equipment placement (put the mask & helmet on it while I'm putting on my fins). I was in waist-deep water, and knelt down to get the Nautilus into the water. It's very buoyant before flooding, and it took about 20 seconds to flood the unit. After flooding it, I pushed off into deeper water, and was neutrally buoyant. I was using a Dacor Pacer regulator, and it breaths very well. There was a bit of current, so I went through it to a eddie, grabbed a rock, and checked out the unit. With no air in it, it handled very nicely in the water. I could feel little resistance, even though it's pretty big. Dacor in its publication says that this is because it is hard-shell, and the water flows around it well.
I pushed off, went under the heavy current, and into the upper eddie, where I surfaced to see the river downstream of my area. There were two fisherman across the river, but I don't think they saw me. Ducking down into the water again, I dived into deeper water. The current took me over some rocks, and into the 20 foot deep channel. I felt the wet suit compressing, and its resultant loss of buoyancy. On the bottom, I grabbed some steel rebar sticking out of the bottom (used to be a bridge here), and checked buoyancy. I was heavy, and so opened the bottom valve, and toughed the Nautilus regulator to add a bit of air. Not enough, so I added some more, and became neutral. Closing the lower valve, I then let go and began exploring the deeper water. I was truly neutral, and the swimming was easy.
After looking it over, I decided to test the Nautilus. I wanted to see whether the advertised strength of the Nautilus, that you only have to set your buoyancy once, actually worked. So I surfaced slowly from 20 feet. At about five feet underwater. the unit vented (through the overpressure relief valve). I surfaced, but did not have excessive buoyancy. I looked around to see whether there were any boats, or fishermen. Not finding any, I submerged again feet-first without problem, and headed for the bottom. At about fifteen feet, I heard the regulator automatically feed air into the Nautilus. I arrived at the bottom again at neutral buoyancy. The Nautilus had passed the test. I did not need to put any effort into the unit at all.
I explored the area, and let the current carry me downstream. The river gets shallower, and my wet suit expanded when I was in about 9 feet of water. Because of this, I did need to vent the Nautilus once more to attain neutral buoyancy. I then was free to enjoy the dive. I did not see fish this dive, but wondered where I was in the river. I looked up, and saw the footbridge through the water's surface, and knew I had about 100 more yards to go before my exit.
I was monitoring my air closely, as I had started with an 80 cf tank at 1500 psi (half full), but this was adequate for my dive). I surfaced downstream of the foot bridge, near my exit, and saw that the ducks were asleep where I got out. I submerged again, went right to where there were, and slowly surfaced. One duck woke up. I needed to vent the Nautilus of water, and so started adding air. As I got higher in the water, more ducks woke up. Then I stood up in waist-deep water, and they took off. That was fun.
I played around with the Nautilus on the surface, leaning back and letting it float me high out of the water on my back. I was able to travel quite fast kicking on my back with this unit. Then it was time to exit, walk up the river bank and back to the car. That was the workout for the dive, but not too bad either. All in all, a very enjoyable dive.
The Nautilus provided me with a different type of dive, one that is vintage and modern all in one. It was single-hose time (with several hoses), but with a unique unit that has not been made since about 1980. I will be using it more in the river, and have plans for some lake dives out of my canoe next summer. It will be easy to dive from the canoe, as I can simply throw it in the water, and put it on in the water. I'm looking forward to that.
John
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Post by SeaRat on Jul 3, 2009 20:34:29 GMT -8
Well, I've had two dives this season with the Dacor Constant Volume System (CVS), and I am becoming more and more impressed with this unit. Today, rather than carry the unit to the water on my back after donning full gear, I took the Dacor CVS with the Pacer regulator to the water before getting into my dive gear. I set it down next to a rock just in the river. I then went back up to my rig, got into my wet suit and brought my wet suit, mask, fins, helmet (with snorkel), knife, and forward swim unit to the water. I didn't need a weight belt, as I had 12 pounds of weight in the CVS weight channel. When I got down, I floated the CVS near me, put on my swim gear, then got the CVS, opened its water inlet valve, and pushed up on the push rod assembly to open the overpressure relief valve. This began flooding the buoyancy chamber, and I stopped it when the CVS unit and scuba became vertical. It still floated, but this made it very easy to get into in the water. I got into the shoulder straps, then cinched down the waist strap and put my safe second on a neck strap, then was set to go. I moved into deeper water, flooded the unit completely, and submerged to dive.
My goal was to swim underwater into the upper pool, but my shoulder straps were a bit too loose. So the unit tended not to move with my body in my dolphin kicks. This caused it to catch the currend, and made swimming against the current problematical. So I went downstream and into the second pool, where I surfaced near the back and inflated the CVS until it was again vertical. I got out of the straps, and took about three inches out of the shoulder straps. I then got back in, flooded the unit completely, and then submerged and swam. This time my dolphin kicks were in synch with the unit, and it hugged my back well. I swam down into deeper water, with the current, and went into the deep section at twenty-two feet. I could fairly easily swim against the current. I made some swims around the area, then came to an areas under the rocks where I noticed "my" red-sided shiners congregating. The water was warm (I was in the top half of my wet suit, with a hood mainly for sunburn protection) at just over sixty degrees. I wedged myself into the rocks and began observing the red-sided shiners. Sure enough, they were not only in mating colors (their red sides), but also they were mating. I watched a group of about 50 fish gathering around at ten or so individuals at a time, chasing a female and witnessed the actual mating on the rocks. This time they were mating in smaller rocks than I had seen in the Umpqua River in the 1980s and 1990s. I watched this happen for about ten minutes, then watched a large-scale sucker come in and begin trying to feed where the mating had occurred (apparently looking for eggs). The shiners seemed to try to chase this one fish, about three times their size, away. Then I saw what looked like two Umpqua Northern Pike Minnows, again many times bigger than the fish. I had witnessed them eating red-sided shiners in the North Umpqua River, but that did not happen here. They may have been inhibited by my presence. The shiners did react to my bubbles, and I wash I was using my two-hose regulator (not as good with the CVS though). But they did not react overly, and returned to right under my nose when I held my breath.
After twenty minutes of observation of the red-sided shiners, I pushed off and went slightly downstream. To my delight, there were more red-sided shiners in the water column who had not yet changed colors to their mating colors. That means this has just started, and we have another week or so of mating. In amoungst the red-sided shiners, there was one salmon smolt, apparently using the school of shiners as a shield. He stayed with the shiners, even though he was the only salmon smolt (probably Chinook) in the school. I had also seen this in the North Umpqua, but this was the first time here in the Clackamas River.
I swam upstream again, to get an idea of how the swimming technique and the CVS worked, and found that they worked pretty well together. I could make good headway against a pretty solid current, even though the CVS is a pretty bulky system (I would do better with a single tank, but wanted to know this bit of information).
I then headed downstream, and swam toward my exit. When I got there, I was at about 600 psi with the J-valve up. I reached way around to pull the J-valve, did so awkwardly (I will recommend not using the J-valve with the CVS). I was then at about 800 psi (the real amount in the tank), and so surfaced, and decided add buoyancy. To do this with the CVS, you open the water inlet valve (which also lets the water out) and hit the inflation regulator with my thumb on the left side. Immediately the water was being displaced by air, and when the water inlet valve started bubbling, I had all the buoyancy the unit could provide (about 50 pounds). I then swam on my back mostly out of the water, in current, two-thirds across the river in about a two-know current, with ease. I flooded the unit again, and explored this section of the river that I had not seen before, and saw some deeper areas than I had known. I then swam across the river underwater and found that I had made progress upstream too. Finally, I surfaced, blew the unit free of water again, and exited.
As I was walking back, a man covered in tattoos was walking his dog in the park path, and asked me what I had found. I told him that there was a "whole lot of sex going on in that river," and explained the mating that I had seen. I told the lifeguards about that too, after getting out of my gear (I always tell them when I have exited the river). Anyway, I thought you would like to hear this story, and I will resurrect this thread at the same time.
John
PS, the photo below is of the red-sided shiners spawning in the North Umpqua River
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Post by diverdon on Aug 22, 2014 11:04:08 GMT -8
Hey John,
Thanks for posting this with such great detail. You haven't posed anything about the CVS in a while. Have you used it much since? Do you still have one or two? Just curious.
Thanks,
Don
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Post by nikeajax on Aug 22, 2014 11:30:14 GMT -8
Tell the nice man why you're asking...Don!
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Post by diverdon on Aug 22, 2014 12:05:06 GMT -8
Snicker. In good time my friend. In good time
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Post by SeaRat on Aug 22, 2014 13:27:31 GMT -8
Don, I havent't dived it since I sent my main one to Robert a while back. I am thinking about diving my incomplete unit tomorrow, but need to set it up to do so. The first one is the one pictured above, and I dove it with my Hydro-Twin. If I dive it tomorrow, I will use my AMF Voit Trieste II on it. Here is the complete one I sent to Robert. (this will take a few minutes, as I'm eating lunch.) The problem with the one I currently have is that it does not have the CVS regulator, and so I must leave the chamber open when I dive (go deeper). This negates to some degree the constant volume aspect of the system (Constant Volume System). I did put a dive regulator on it early, but then I got the second, complete unit which is now in California. The photos below are of the complete unit, and show the side view, end view, and without a tank showing the use of weights. These weights are regular weight belt weights, but I also have a mold to make weights. The mold weights would by five pounds each, whereas the weight belt weights, which just barely fit the chute, are four pounds each. The tank is a USD steel 52 cubic foot tank, but it will accept a single 72; it was made for a single AL 80 cubic foot tank. Note that any tank used must be used without a tank boot for the weight chute to work in an emergency. John
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Post by diverdon on Aug 22, 2014 18:28:51 GMT -8
Hey John, thanks. I read your posts here and on S-boards. I was happy to read that you had a mold for the weights. As JB eluded to earlier, I have one coming and I'm geeked to try it out. I've been seeking info and of all the threads I've found yours were most informative. I'll start a new thread when I get it.
Thanks,
Don
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Post by nikeajax on Aug 22, 2014 20:22:31 GMT -8
Hey Don, now ya gotta get yer Olympic workin', 'cause the Nautilus esposta have a Olympic don'cha know... (did'ja like my grammar?) Jaybird
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Post by SeaRat on Aug 22, 2014 22:17:17 GMT -8
I'm going to dive my other Nautilus CVS tomorrow, and have it set up on a steel 72. The regulator will be an Olypmic first stage and octopus, and the newer Dacor second stage (name escapes me right now). It has about 9 pounds in it right now, and I may need to wear about 10 pounds on a weight belt too. I was thinking of using my shorty wet suit, but think I need the long wet suit tomorrow because we've had some cool nights. This may motivate me to convert some fishing weights to CVS weights soon. Don, when you get yours why don't you keep it on this thread so we'll have the knowledge of the Dacor Nautilus CVS all in one place. John
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Post by diverdon on Aug 23, 2014 3:52:49 GMT -8
Good idea John. Will do
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