SCUBA vs. Surface Supplied Air

It is safe to say that the majority of public safety dive teams train using Self Contained Underwater Breathing Apparatus (SCUBA) equipment. The training for SCUBA is readily accessible and the equipment relatively inexpensive. SCUBA is also easy to maintain and transport. Teams with large budgets, or more diverse areas of responsibilities, may have acquired and trained with Surface Supplied Air (SSA) equipment. SSA equipment is more expensive, requires specialized training and the components require large areas for storage and deployment. Due to these comparisons, public safety dive teams use what they have on hand, SCUBA equipment, to conduct their missions. However, there are times when a public safety dive team may want to look outside their normal operations in order to save time and money executing a mission.

Our Police Department recently took a report of 60+ handguns stolen during a burglary. There was no sign of the stolen weapons until a local fisherman brought in a rusted and corroded handgun he stated that he hooked while fishing from a local pier. When the gun was confirmed stolen from that burglary, the dive team was assigned to check the area for more stolen weapons. The team took the fisherman to the location and he did his best to describe where he was fishing when he hooked the stolen weapon. While evaluating the search area, it was obvious that it could be wide and vast. The fishing pier was long with a 90 degree turn and all of it accessible to the water. The suspect could have thrown the additional weapons at numerous locations.

The pier was at such a height above the water line, even at a high tide, that it would have been a dangerous drop to the water. There was also no way to help a diver in the water with recovering a weapon. The dive team decided to use the equipment at hand, SCUBA, and the dive boat, in order to stay close to the water, even though it was not the most stable platform. During the first mission, two weapons were recovered. This required two divers, one boat operator, 4 SCUBA cylinders and approximately 4 hours.
After this initial recovery dive it was determined that a large number of the stolen weapons could have been dumped in this area. Looking at logistics, it could take several days, numerous cylinders and numerous personnel, many on overtime, to thoroughly check the area and recover all of the potentially dumped weapons. Like every team, ours needed to monitor the budget of the dive mission to keep the support of the department. We decided that we needed to come up with a more feasible, cost effective plan.
Our team did not have Surface Supplied Air (SSA) equipment, but one of our members did. The dive team member had the SSA equipment and some volunteers to help tend topside on the boat. The reason the team thought about using SSA equipment was due to analyzing the time necessary for a SCUBA diver to change out his cylinder every 40 minutes while diving at approximately 40 feet. Using SSA, there is no changing of a cylinder and the diver can stay down as long as he avoids decompression. At 40 feet decompression did not become an issue until over 2 hours.

Surface supplied air equipment is costly, and difficult to set up, but it has numerous advantages over SCUBA. As long as the compressor runs, the diver has air. If the compressor stops, the diver has an emergency air supply located on the boat, as well as an emergency bailout bottle mounted on his back. The diver is attached to an umbilical line, which contains the air hose, as well as a safety line and communication line. The communication is hard-wired; therefore it is more reliable than wireless systems. Another advantage is that the umbilical line can also act as the search pattern line.

For the next search mission, using surface supplied air, the dive boat was located just under the pier. When the SSA diver went down, the tender controlled his search pattern. The diver started at the location estimated to be the farthest possible for any person to throw an object. A search pattern was used to slowly work the diver back towards the fishing pier. The first two hours concluded with negative results. However, the depths were shallower than previously planned, and the diver was able to stay in the water. After 2 hours in the water, the diver recovered the first weapon. The dive mission continued for an additional 1 hour and 15 minutes, with a total recovery of eight more stolen weapons. The total dive time was 3 hours 15 minutes using SSA and 2 Aluminum 80 SCUBA cylinders.

The SCUBA cylinders were used by a group of two back-up divers. The SSA diver would communicate that a weapon was located. Topside would send the SCUBA diver down the umbilical line to the SSA diver. The location was marked and the weapon placed into a bag. The SCUBA diver would then bring the weapon to the surface. In the meantime, the SSA diver would continue with the search pattern, never having to leave the bottom, and never losing his location or doubting if an area had been fully searched.
Using surface supplied air equipment, the dive team was certain that the entire area had been searched. One diver stayed in the water using SSA, staying well outside decompression exposure limits. The backup divers were only used as safety divers and to retrieve the recovered weapons. This limited the amount of air used and their decompression exposure. The entire operation was completed in one day, and with less than 5 hours of actual mission time. This time reduction saved the dive team and department thousands of dollars in overtime, equipment maintenance and fuel costs.

I am not advocating that all teams spend the time and money outfitting for surface supplied air operations. The costs are exorbitant related to the actual number of missions where SSA is more feasible than SCUBA. However, there are times when other styles of diving, such as SSA, can save the team money and make the mission safer. The dive team needs to think outside the box, analyzing what they are looking for, where they are looking and the costs of completing a successful mission.
There is one more concern not covered in this article. Like the saying goes…. Cost of surface supplied air equipment and training: thousands of dollars. The cost of a SSA diver investing in a urine dump valve: PRICELESS.

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5 replies
  1. Steve
    Steve says:

    I would not say that surface-supplied air is “difficult to set up.” It is more time consuming because there is a bit more gear, but it is by no means difficult, if you have been properly trained. It’s certainly easier than setting up a rebreather.

    Reply
    • MAX HAVOC
      MAX HAVOC says:

      Hi Steve. As a cert diver si 1976 (diving si 1968) and a PADI Divemaster si 1978,NAUI Inst SI 1984, IT for NAUI si 1994 and SDI/TDI si 1996 as well as a SNUBA IPC si 1997, the ease of setting something up is all relative on choice of equipment, training, and actual use. Knowing your SSA or knowing your SCUBA or even your re-breather set up makes the “ease of setting it up” very dependent on how familiar and in practice you are with your system. Hooking up hoses to a floating tank and strapping on a simple harness for the regular user of SSA (tanks) is quite a snap an effortless.No more gear than a floating BC unless hose length is a bone of contention. If the same effort is to be compared to setting up a SCUBA unit and slinging it on or getting it into the water and “donning” it with all the same in reverse to get out, …well, both have there advantages over each other given the environment and demands. I loved the SSA in open water without overhead obstruction and kelp or other entangling environments I will take SSA any day over SCUBA for open water reef exploration. That is an open water depth regulated preference that lends itself to comfort and unobstructed reef exploration or certain types of work. That narrows it considerably, however, as SCUBA does have a degree of independence that SSA can never achieve. Again, easier is relative. In any case, anyone considering SSA should have the proper training and understand the value of even the smallest of bail out air systems. Great comment, Steve-o!

      Reply
  2. Robert Fitzsimmons
    Robert Fitzsimmons says:

    Wow! well said i’m pleased to see people are learning to utilize the right tool for the right job! Taking in to account appropriate mission assesment and task there are dive equipment options! Teams are looking for approval for those options! Lets not forget there are more reasonalble cost effective forms of SAS suitable to appropriate conditions and are within financial means of dive teams. I am refering to Shallow water diving hookah type units. I feel these units have a place in PSD and provide a basic SAS training platrform. Just a thought! One step at a time and another viable tool in the PSD tool bag!

    Reply
  3. Cassandra
    Cassandra says:

    Excuse my ignorance but is Solo Surface-supplied diving possible? Additionally, can you hear the diver’s breathing from the surface through the equipment?

    Reply
  4. MAX HAVOC
    MAX HAVOC says:

    As a cert diver si 1976 (diving si 1968) and a PADI Divemaster si 1978,NAUI Inst si 1984, IT for NAUI si 1994 and SDI/TDI si 1996 as well as a SNUBA IPC si 1997, the ease of setting something up is all relative on choice of equipment, training, and actual use. Knowing your SSA or knowing your SCUBA or even your re-breather set up makes the “ease of setting it up” very dependent on how familiar and in practice you are with your system. Hooking up hoses to a floating tank (tank system) and strapping on a simple harness for the regular user of SSA (tanks) is quite a snap an effortless.No more gear than a floating BC unless hose length is a bone of contention. If the same effort is to be compared to setting up a SCUBA unit and slinging it on or getting it into the water and “donning” it with all the same in reverse to get out, …well, both have there advantages over each other given the environment and demands. I loved the SSA in open water without overhead obstruction and kelp or other entangling environments I will take SSA any day over SCUBA for open water reef exploration. That is an open water depth regulated preference that lends itself to comfort and unobstructed reef exploration or certain types of work. That narrows it considerably, however, as SCUBA does have a degree of independence that SSA can never achieve. Again, easier is relative. In any case, anyone considering SSA should have the proper training and understand the value of even the smallest of bail out air systems.

    Reply

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