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For the in-water part of the evaluation, each raft in the forest two tests was inflated by one of the virgins who were given approximately 30 seconds to read any instructions for deployment, identify the deployment options and either deploy the raft or attempt to deploy the raft, using the mooring line. Our other virgins were not allowed to view this procedure to ensure they had no prior knowledge of any other raft's inflation procedures upon which to draw when it was their turn. For the 2000 tests, due to the large numbers of rafts, we only used virgins for one of each manufacturer's rafts or valise styles.
If necessary, I intervened to provide instructions. The procedure was for the volunteer to toss the raft into the pool, pull out any slack in the mooring line and give a sharp jerk on the mooring line. Ideally, the raft should inflate without pulling it all the way back to the aircraft where it could be harmed, but in most cases the raft was pulled back to the wall of the pool before inflation commenced. The TSO specifies that only 20 - 30 pounds of tension be required to actuate the inflation sequence.
In the first series of tests, we did not time inflation. The second set of tests were timed. We timed inflation until the raft was firm enough to board using the provided entry aids and to full inflation, including canopy where appropriate, and also where appropriate, how fast the ballast bags filled. The survival equipment pack(s) (SEPs) were removed from the rafts to try to prevent unnecessary water damage to the contents, though with some rafts, the separate packs were waterlogged before we could retrieve them from the water. Those packed inside the rafts tended to stay drier. Items required for the tests were retrieved from the packs where necessary.
TIP: Don't let the hissing worry you after the raft inflates. Life rafts are equipped with pressure release valves (PRVs). Under all but the coldest conditions, the gas cylinder contains much more gas than is needed to inflate the raft. The hotter it is, the more excess gas there is. Once the raft is fully inflated, the PRVs open up to allow the excess gas to vent. Actual working pressure in most life rafts is approximately 1 to 2 psi. When the PRVs open up there is a loud hissing that will continue for some time after the raft is fully inflated. While it sounds like the raft is leaking air, it's only the PRVs doing their job and it is no cause for concern. Note that one manufacturer, Air Cruisers, includes plugging the PRVs immediately after the initial inflation in their immediate action instructions. This would preclude this venting.
Something else you may notice when the raft inflates is ice or frost forming on the buoyancy tubes, even when it's quite warm out. The CO2 (and Nitrogen in many cases) from the inflation cylinder expands rapidly and causes the gas to cool down below the freezing point of water. Thus any water vapor in the air in contact with the cold tube or water on the tube surface freezes. It disappears rapidly in all but the coldest climates and is no cause for concern.
We also tested righting the raft. In most cases this required us to turn the raft upside down after inflation because virtually all the rafts inflated right side up.
For the second and third series of tests the raft was then moved to the center of the pool for boarding and stability tests, once the waves had reached constant height, about 3.5 ft on average. We tested boarding in a number of configurations and bringing of an unconscious survivor on board. If the canopy required erection, this was also accomplished with the waves operating. We then capsized the raft by using the weight of the testers all gathered to one side and then righted the raft again.
After these tests the waves were turned off and the raft moved to the shallow end for freeboard measurements and simulated rain and weather tests. The first series of tests were conducted essentially in the same manner, but obviously, without benefit of the waves.
Inflation was a mixed bag. We had anticipated the possibility that a raft might not inflate or might blow up, based upon reports we had received from others who had tested rafts previously. Neither problem raised it's ugly face. What we weren't expecting was the extreme difficulty experienced in getting some of the rafts to inflate.
The Air Cruisers, Hoover, Survival Products, RFD, BFGoodrich and Winslow rafts operated like a charm with no problems. The Winslow took the least effort, the RFD the most. (The original style BFGoodrich rafts in our first test both required a number of tries to get them to activate. In the end it took a mighty hard jerk to get the job done. We considered that unacceptable)
While the Survival Products rafts operated satisfactorily in our tests, in other venues we have seen a rash of failures to inflate, partial inflations and one blow-out. In all these cases the rafts were not brand new or provided by Survival Products, but all had current inspection certificates.
The EAM raft in our first test simply couldn't be inflated in the conventional manner, despite ten tries. In the end, I had to get in the water, brace both feet on the raft and pull on the line with considerable force to get it to work. I consider this a critical failing. I have seen others have similar problems with EAM rafts in other venues. Other EAM rafts and those sued in our second and third series of tests have operated without difficulty.
This inconsistency is troubling, no matter the root cause. It should not be designed such that it occurs with such alarming regularity. While other rafts, Hoover, old style BFGoodrich and other rafts no longer available have occasionally been harder to pull and inflate than might be desired, none have been so difficult as to require the effort we had to make on these EAM rafts, an effort that might preclude timely inflation in an emergency.
The valise of the RFD Navigator just begs to be opened up by the uninformed. After turning the valise over a couple times and then reading the instructions, our volunteer tried to rip open the Velcro seam, which I prevented. The raft inflated easily at the end of it's too short tether/inflation line. There is no obvious handle with which to pull, just a small loop, too small to easily grip. Inflation time was 7 seconds for the raft, 10 seconds for the canopy. The ballast bags filled within 7 seconds.
The RFD "R" series raft was large enough that we had two volunteers perform the inflation. The two volunteers took 25 seconds to locate the inflation/mooring line. Inflation time was 22 seconds for the raft which included the time until the boarding ramp was inflated and useable. The ramp was the last part of the raft to inflate, seconds after the rest of the raft was firm.
All the Winslows are very similar as far as inflation goes. Regardless of size all inflated within 15 seconds. smaller sizes within 11 seconds. Canopies erected within 12-20 seconds depending upon size. Ballast varied a good deal from 15 to 60 seconds.
The BFGoodrich 10 person inflated in 20 seconds, the canopy in 25 seconds and the ballast bags filled in 15 seconds. This may not be typical of production rafts with significantly changed buoyancy tube sizes and canopy inflation design, but they should not be significantly different.
The Air Cruisers 4-person raft inflated with no problems in just 13 seconds. We had some difficulty whit the 13-person raft. It took four tries to get it to inflate. In the end we yanked so hard it almost came all the way up the four foot wall to the pool deck before finally inflating. It was obvious when reviewing the tapes that it was the vacuum bag that was causing the problem. There's no question that this raft does not meet the TSO specifications by any stretch of the imagination. However, before you fault the vacuum packing entirely, note that many of the marine rafts we tested were vacuum packed, including thee manufactured by Air Cruisers' parent, Zodiac. They are inflated easily without any such heroics. We consider this a serious problem.
Survival Products, Hoover and EAM all inflated in the 10-15 second range, but no canopies, of course.
By and large, all the rafts inflated quickly enough so that we don't feel that inflation time at warmer temperatures is a significant concern. Inflation time in colder weather is the real concern, testing we could not perform ourselves. Our discussions with a few of the manufacturers tend to lead us to believe that at least with the high end rafts, this has been adequately addressed since it is what has been the major design point for the inflation system. Meeting the cold inflation specification is the critical performance test and once that is met, the rest falls more easily into place. Non-approved rafts, which don't have to meet such standards, are more of a concern for us.
On the other hand, anyone using their raft exclusively in especially hot climates, may want to discuss that with the manufacturer. Pressures in the gas cylinder have been known to get so high they exceed the rating of the system's pressure release valve, causing a failure. A different pressure release valve or lower charge for the cylinder may be appropriate.
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