Deep dives with Argonaut Double hose
General dive descriptions:
I just got back about a week ago from the Dahab in the Red Sea, Egypt. We did a series of deep dives with two of them in the Blue Hole just north of Dahab. One dive was to just under 210 ft of depth and the las t one was to 305 feet.
We were using TriMix for the bottom gas and for the travel gas during the deepest dive.
My primary regulator for my bottom gas was my Argonaut mounted on my back cylinder. I carried my bottom gas mixture on my back cylinder and my right “side mounted” cylinder. A low pressure quick disconnect hose allowed me to select from breathing my back gas or from the right cylinder (with the same mix). The right cylinder had a Conshelf first stage with a long hose to a Scubapro 109 for gas sharing if needed.
I carried my deco cylinders on (Nitrox 32 and 100% Oxygen) on my left side. The Nitrox 32 was in an AL80 and the O2 was in an AL40 below it.
For the Nitrox32 I used another Conshelf with a Scubapro 109 second stage. For the Oxygen, I used an oxygen clean unbalanced piston (DGX brand) first stage with another Scubapro 109 second stage. The unbalanced piston regulators are IMO the best choice for higher O2 gas mixes specially for pure O2.
For the first dive in the Blue Hole, we were using TMx 18/30 (18% O2, and 30 helium). We did start with the Nitrox 32 as a travel gas down to 110 ft in order to save a bit on the cost of helium.
For the deepest last two dives, we were using TMx 13/50 (13% O2, and 50 helium). With that low oxygen content, we needed a travel gas and therefore we added a 5th cylinder with TMx 20/20.
Note: these are not standard gas mixes, but they were readily available at out support dive shop in Dahab. BTW, I already got plenty of friendly comments about the non-standard mixes… My answer is: that is not the only thing non-standard…
We had surface support from the dive shop with personnel assistance that would actually carry all our side cylinders into the water. The assistance made for the easiest shore diving experience that I can think of.
The Blue Hole in Dahab has an arch at around 175 ft deep, with a fairly large opening going out to open ocean. The bottom of the Blue Hole has a steep slope, but just under the arch the depth is about 300 ft and continues down into the open ocean.
A lot of divers have attempted going through the Blue Hole under the arch using a single AL80 with air. Many unprepared divers have died attempting such a dive (over 200 documented).
A lot of people have asked me if I saw any bones at the bottom of the arch. The answer is no. If the bodies are not recovered shortly after the incident, they get swept out to sea. I have heard that some remains can be found down around 600 ft depth. Well beyond any depth of interest to me.
Equipment observations.
First, I was extremely pleased with the performance of my Argonaut. I have been diving this Argonaut now for many years and it is just super. I will get into some of the improvements I have done to my Argonaut in following posts, but I will say the second stage has been adjusted to the max-possible venturi assistance.
I have used this regulator down to 180 ft and the performance has always been outstanding. With my new DSV flow diverter I have taken the venturi flow performance to a new level.
During these dives with the helium in the TriMix, the performance was just beyond outstanding… With 50% helium, I felt very comfortable and clearly remember every detail of the smooth performance.
Also, a very impressive observation was the drastic noise difference every time I switch from my side gas regulators (single hose) to my back gas. I have always known there is a difference, but the repeated switching created a contrast in noise level that was dramatic.
Some friends thought that maybe the noise just switched from front to back, but that is not exactly the case. One of the unique modifications I have been working on the last two years (since Covid) has been on my exhaust bubble silencer. More on that later, but it definitely works.
The position of the side cylinders needs some improvement, but they did their job without any issues. My right cylinder in particular needs adjustment, but both sides can use it.
The configuration I used is what I called mix-mount, it draws from side mount and back mount, but most of my testing and cylinder position tuning has occurred here in Maine with cold water equipment. The transition to 3mm shorty with aluminum tanks requires a bit more refinement.
I have written about this configuration in these threads and I may be adding more information in the future. I am very pleased with this setup.
Argonaut Mix-mount or Tri-mount… as opposed to side-mount
Argonaut Mix-mount or Tri-mount… as opposed to side mount - Vintage Double Hose
I will be writing more about some of the work I have doing to the Argonaut (the exhaust silencer and my new DSV flow diverter, etc.), but for now here is the dive profile of a couple of my dives and below is a link to a video. I do not have any pictures of the dives. I don’t even have a camera housing rated to these depths.
Note: The breathing noise in this video is all from the diver holding the GoPro.
From looking at the videos I already established that I need to clip my side mount cylinders lower on my waist, not on the butt plate. This is particularly true with 50% helium. Even when it is full, the content in that cylinder is about 36% to 40% lighter. I would have made some corrections on the spot, but at the time it didn’t feel bad. I should have moved some weights… Oh well.
Most of the testing of my “mix-mount” set-up was done in cold water with a drysuit or heavy wetsuit. For the earlier dives I used small steel side cylinders, very heavy (worked great with a drysuit).
General dive descriptions:
I just got back about a week ago from the Dahab in the Red Sea, Egypt. We did a series of deep dives with two of them in the Blue Hole just north of Dahab. One dive was to just under 210 ft of depth and the las t one was to 305 feet.
We were using TriMix for the bottom gas and for the travel gas during the deepest dive.
My primary regulator for my bottom gas was my Argonaut mounted on my back cylinder. I carried my bottom gas mixture on my back cylinder and my right “side mounted” cylinder. A low pressure quick disconnect hose allowed me to select from breathing my back gas or from the right cylinder (with the same mix). The right cylinder had a Conshelf first stage with a long hose to a Scubapro 109 for gas sharing if needed.
I carried my deco cylinders on (Nitrox 32 and 100% Oxygen) on my left side. The Nitrox 32 was in an AL80 and the O2 was in an AL40 below it.
For the Nitrox32 I used another Conshelf with a Scubapro 109 second stage. For the Oxygen, I used an oxygen clean unbalanced piston (DGX brand) first stage with another Scubapro 109 second stage. The unbalanced piston regulators are IMO the best choice for higher O2 gas mixes specially for pure O2.
For the first dive in the Blue Hole, we were using TMx 18/30 (18% O2, and 30 helium). We did start with the Nitrox 32 as a travel gas down to 110 ft in order to save a bit on the cost of helium.
For the deepest last two dives, we were using TMx 13/50 (13% O2, and 50 helium). With that low oxygen content, we needed a travel gas and therefore we added a 5th cylinder with TMx 20/20.
Note: these are not standard gas mixes, but they were readily available at out support dive shop in Dahab. BTW, I already got plenty of friendly comments about the non-standard mixes… My answer is: that is not the only thing non-standard…
We had surface support from the dive shop with personnel assistance that would actually carry all our side cylinders into the water. The assistance made for the easiest shore diving experience that I can think of.
The Blue Hole in Dahab has an arch at around 175 ft deep, with a fairly large opening going out to open ocean. The bottom of the Blue Hole has a steep slope, but just under the arch the depth is about 300 ft and continues down into the open ocean.
A lot of divers have attempted going through the Blue Hole under the arch using a single AL80 with air. Many unprepared divers have died attempting such a dive (over 200 documented).
A lot of people have asked me if I saw any bones at the bottom of the arch. The answer is no. If the bodies are not recovered shortly after the incident, they get swept out to sea. I have heard that some remains can be found down around 600 ft depth. Well beyond any depth of interest to me.
Equipment observations.
First, I was extremely pleased with the performance of my Argonaut. I have been diving this Argonaut now for many years and it is just super. I will get into some of the improvements I have done to my Argonaut in following posts, but I will say the second stage has been adjusted to the max-possible venturi assistance.
I have used this regulator down to 180 ft and the performance has always been outstanding. With my new DSV flow diverter I have taken the venturi flow performance to a new level.
During these dives with the helium in the TriMix, the performance was just beyond outstanding… With 50% helium, I felt very comfortable and clearly remember every detail of the smooth performance.
Also, a very impressive observation was the drastic noise difference every time I switch from my side gas regulators (single hose) to my back gas. I have always known there is a difference, but the repeated switching created a contrast in noise level that was dramatic.
Some friends thought that maybe the noise just switched from front to back, but that is not exactly the case. One of the unique modifications I have been working on the last two years (since Covid) has been on my exhaust bubble silencer. More on that later, but it definitely works.
The position of the side cylinders needs some improvement, but they did their job without any issues. My right cylinder in particular needs adjustment, but both sides can use it.
The configuration I used is what I called mix-mount, it draws from side mount and back mount, but most of my testing and cylinder position tuning has occurred here in Maine with cold water equipment. The transition to 3mm shorty with aluminum tanks requires a bit more refinement.
I have written about this configuration in these threads and I may be adding more information in the future. I am very pleased with this setup.
Argonaut Mix-mount or Tri-mount… as opposed to side-mount
Argonaut Mix-mount or Tri-mount… as opposed to side mount - Vintage Double Hose
I will be writing more about some of the work I have doing to the Argonaut (the exhaust silencer and my new DSV flow diverter, etc.), but for now here is the dive profile of a couple of my dives and below is a link to a video. I do not have any pictures of the dives. I don’t even have a camera housing rated to these depths.
Note: The breathing noise in this video is all from the diver holding the GoPro.
From looking at the videos I already established that I need to clip my side mount cylinders lower on my waist, not on the butt plate. This is particularly true with 50% helium. Even when it is full, the content in that cylinder is about 36% to 40% lighter. I would have made some corrections on the spot, but at the time it didn’t feel bad. I should have moved some weights… Oh well.
Most of the testing of my “mix-mount” set-up was done in cold water with a drysuit or heavy wetsuit. For the earlier dives I used small steel side cylinders, very heavy (worked great with a drysuit).
for posting this cutting-edge approach in the "Vintage Double Hose" forum. (There is nothing vintage about your extraordinary setup.) 
