The Pacific Northwest is well-known on both sides of the border for technology and innovation in many fields of endeavor – it is only natural that diving would be one of them. There are many companies in our little corner of the planet producing products that have made the rest of the world take notice – one such is Jetsam Technologies, Ltd. in Port Moody, British Columbia, the designers and builders of the KISS rebreathers. Founded by the late Gordon Smith, the company produced its first rebreathers for the commercial market in 1999, selling the first five units that year of what would become the "Classic" KISS Closed Circuit Rebreather. Since then hundreds of the "Classic" model CCR have been distributed worldwide and are in use on all continents of the world. A second model designed for traveling, the "Sport KISS", was also released in 2004 and was immediately popular.
A tool and die maker by trade and fascinated by precise design, Gordon took to heart the philosophy, "Keep It Simple Stupid", and incorporated it into his designs. It seemed only natural that the KISS philosophy would be the cornerstone of the rebreathers he built, so Gordon decided on that as the basic name for his products and the KISS line of closed circuit rebreathers (CCR) was born. Knowing that he was building a machine designed to be used underwater and that was life support equipment, he felt strongly about the KISS principle – the units had to be both simple and robust for safety as well as for diver comprehension and understanding. Gordon wasn't comfortable in adding clutter and electronics to his rebreathers - salt water doesn't "play well" with such devices, and trouble shooting by a diver underwater would be both difficult and dangerous. When he began to design his first rebreathers, Gordon Smith was following the footsteps of other innovators spanning almost two centuries…..
People have attempted to build rebreathers for hundreds of years and their use long pre-dated the invention of SCUBA. One of the first working closed-circuit rebreathers was built by Henry Fleuss in 1878 and was an oxygen rebreather. Draeger, now well known for their Dolphin and Ray semi-closed rebreathers, worked on both closed and semi closed systems in the early 1900's. Later, several of the warring nations used rebreathers during World War II, that conflict greatly expanding interest in rebreathers for military purposes. The first electronically controlled rebreather was produced in 1968 and in 1996 a semi-closed Nitrox rebreather was marketed by Draeger for recreational diving, following which several other companies started to design and develop rebreathers. The success of functioning rebreathers was largely made possible by the advent of reliable oxygen sensors.
With "regular" scuba diving, (also known as open-circuit diving or OC), the gas the diver breathes is exhaled into the water column. In rebreather diving, the gas that the diver exhales is recycled. Basically, instead of exhaling bubbles into the water, the exhaled gas is channeled through a "breathing loop" into a chemical "scrubber". The scrubber removes the carbon dioxide from the breathing gas, and oxygen along with a diluent gas (air or Trimix) is added as required. The "scrubbed" gas is then available to be re-breathed and the cycle starts all over again. Rebreather diving can be either semi-closed (SCR) or closed-circuit (CCR). With most semi-closed units there is a constant flow of bubbles into the water column. This is due to the high constant flow of gas into the breathing loop. With a closed-circuit unit, however, only the required amount of gas enters the loop so there is no need for constant venting. Therefore, while at a constant depth, there will be no bubbles released into the water. When the diver ascends, there will be some bubbles as the gas in the loop expands and is released. This is basically the same principle as with a BCD or drysuit. Both models of the KISS rebreathers are closed-circuit rebreathers.
While many CCRs are designed with electronic controllers, alarms, and other "bells and whistles", KISS rebreathers are manually controlled by the diver and require that he/she keep track of the partial pressure of oxygen being breathed. Being completely responsible for that is something that sounds frightening, but in fact the principle is quite simple and straightforward. To keep the diver from having to constantly add oxygen, a constant flow orifice ensures that a set small amount of oxygen is always flowing, while additional oxygen is added manually by the diver. This is done by simply pushing the add valve button on the unit. The diver monitors the O2 levels while descending or ascending, adding O2 as necessary to maintain the desired level, then once at the planned depth the orifice will maintain that level. In short, the diver's brain becomes the PO2 monitoring device, and he/she will need to occasionally monitor the displays showing O2 levels. This system incorporating simplicity and diver responsibility in fact works extremely well, and the KISS rebreathers have an excellent safety record that is second to none in the world of rebreathers.
The O2 displays are not computers – instead, following Gordon's KISS principle, they are simple user-calibrated numeric displays that can be easily changed out by the diver in a few minutes, (in fact, the entire unit is completely user maintainable). For extra safety and redundancy a triple display is used - each one of the three reads one of the three separate O2 sensors in the unit, with each display having its own battery and waterproof case. They are thus completely triple redundant. In CCR diving the gas that the diver does not metabolize is recycled. Since every lung-full of gas thus goes much further, smaller cylinders can be used. Using two cylinders, (either 13 cf or 19 cf tanks), one for oxygen and the other for the diluent gas, a diver will have between 2.5 and 3 hours of gas at any depth. Even then, the time isn't limited by the amount of gas available, but simply by the expected life of the scrubber material.
While diving with my Classic KISS unit I have found my dives to be quiet and peaceful. Further, because I am continuously breathing warm, moist gas instead of the cold, dry gas produced with "regular" open-circuit scuba equipment, I find that am able to stay warm far longer when diving in the cold waters of the Pacific Northwest - a significant advantage. To my amusement I have discovered that I can keep track of the location of my "open-circuit" buddies simply by the amount of noise they produce with Scuba. As an underwater photographer, I have found that normally shy creatures are far easier to approach, and my time at depth has been greatly extended, giving me far more photo opportunities than ever before. From black-eyed gobies to massive ling-cod, each creature seems to loiter to see what the large, silent object is. This has added even more wonder to my dives and I look forward to many more such experiences.
The successful completion of specialized training is required before divers can use and safely operate a Closed-Circuit Rebreather. Qualified unit-specific instructors exist worldwide to meet this need.
Jetsam Technologies, Ltd. can be contacted at (604) 469-9176, or through their website at www.jetsam.ca