Dive Log: 10 August 1997, Second Dive with the SA-2 Genesis
For this dive I did have proper trim for the exposure suit I was wearing; I remembered to wear my weightbelt. Thus one potential problem avoided. I did however experience a malfunction of the SA-2 during this dive. (Which does make a little more interesting reading...)
Upon arrival at Ron's house, I just had to dissemble the unit to show him some of the finer points of its construction. Ron was jazzed. After this show-and-tell, the unit was reassembled, but in the process one of the parts was omitted. (Yes, human error. It does happen in the real world.) This missing part controls the flow of gas when the unit is submerged. Of course, this omission was not discovered until I was in the water. A beautifully executed back roll off the boat was followed by a divers "A-OK" at a waist high bouyancy level. It just goes to show you that whenever a problem can occur, it usually occurs at the very worst time. ('Just hate to look bad around the boat.)
So there I was... as we used to say during my flying days. In this case I was in the drink with a free flowing oxygen addition valve, bobbing on the surface like a cork. Not very impressive to say the least. It was a good thing most others were still getting their gear on at the time, and didn't even notice.
The problem was immediately obvious, so I turned off the gas cylinder. If I was going to dive, I would have to dive the rig in "manual". (And I was going to dive.)
In this so called "manual" mode gas is added to the system by opening the valve on the gas cylinder to allow a little oxygen to enter the breathing bag. Then it is closed after a sufficient amount of gas needed to get a full breath is obtained. While breathing, the CO2 is being removed from the system by the scrubber. The total volume of circulating gas is constantly decreasing. Eventually the total volume of gas in the system gets so low that the breathing bag collapses. When this happens one cannot take a full breath. It is at this time that the valve on the cylinder is opened again and more gas (oxygen) is added to the system.
This primitive way of using the unit is a little annoying, but not enough to cancel this dive. In practice, it turns out that you have to add a little gas every minute of so, depending on your rate of CO2 production (and removal), and the amount of gas you keep in the breathing loop.
The dive nevertheless was successful. It was an 18 fsw dive gathering bivalves (they didn't know what hit them), and teaching novice divers small inflatable boat SCUBA exit and entry techniques .
All had a great time, as this was a first for some of the newer divers, not only diving from small boats, but discovering delicious gifts from the sea.
As you can see we reached our limits for Pismo Clams (the limits are 10 per diver and 4.5 inches minimum size). After the dive we returned to Ron's house for a great meal of Baked Clams on the half shell, and Pasta with White Clam Sauce. Ron also grilled some steak, and we washed it all down with some premium California Wine, some premium Milwaukee Beer, and some premium dive stories.
A wonderful time was had by all.
The minor problem which I experienced is one of the many things that can, and will go wrong with these units. The sooner that those who are interested in rebreathers, learn how recognize and deal with problems/malfunctions/emergencies, the more comfortable and safer they will be in using these rigs. This simple O2 rebreather, with few parts and no electronics can have many more, and different problems than that which can be experienced with open circuit Scuba. The emergency procedures to deal with some closed circuit problems can be totally opposite than what is trained and/or expected in open circuit Scuba. You have read my disclaimer about closed circuit diving on a previous page. If you get further involved in this activity insure that your training results in your knowing your rig inside-out, and insure that you can "fly" the rig in various degraded modes of operation. (That's PC for know how to recognize and recover from various emergencies and/or system failures.)