Depends on the distance. Shorter range stuff and I think a team tow scooter is reasonable. For a longer thing you need full coverage. Determining what is "long" is up for debate.
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Depends on the distance. Shorter range stuff and I think a team tow scooter is reasonable. For a longer thing you need full coverage. Determining what is "long" is up for debate.
The scooter has always been felt to be the weakest link in all the dive equipment,for example we have redundant lift,regulators etc. If your propulsion such as scooter is part of your life support,then either have enough gas planned for a safe exit (which should be always) by swimming, or carry a spare scooter for all dives. I never plan for scenarios where if there is a scooter failure and will tow the person out because it is very slow and stresses the gas plan,and nobody really practices it following their DPV class to say they are proficient at doing it. I have seem so many instances of team separation because of scooters,where one team member has an issue to pause,and the other member goes around the corner-now we have two solo divers with Murphy waiting to strike. I have heard enough scooter incidents to fill the IRAP section of this forum,but I recall a team exiting from Manatee and the trailing buddy had an issue and paused. He got back on the trigger and it failed,but by this time the buddy had gone around the curve. The buddy realized after about 1000ft he had no one behind him. He went back and found his buddy,they exhausted gas by trying to figure out what was wrong with the scooter,and exhausted more gas by trying to get into a tow position that would work. The only thing that save their life was they could exit from Friedmen's,but they would never have made it back to Catfish Hotel from where they started. For many this dive was a short penetration,and a spare scooter was never part of the plan,but the spare scooter could have turned this into an inconvenience versus an emergency.Originally Posted by RN
"Not all change is improvement...but all improvement is change" Donald Berwick
So in my opinion there's a few issues about the above story that make me raise an eyebrow.
We've all had some separation when scootering. But a thousand feet? That's like 7mins (ish). To me, that's just way too much and shows a lack of attentiveness by front guy.
Second issue is inappropriate response. On a resource-light dive, you can't fully dally trying to fix things. It's time2go when something breaks, especially propulsion.
Third thing is possibly not great towing skills. Done right it's not that much slower. But there's some odd methods being taught so I can't speak for every possible permutation.
Lastly is an apparent lack of reserve gas. Thirds is just too sporty on a scooter dive. More gas needs to be reserved, and that value goes up the farther you go in the cave.
Just my opinion.
You are right we can dissect that incident and find lots of problem. I have heard many examples of scooter dives that had problems,not this extreme,but were problems where better awareness,planning,and practice were indicated. But is this example too far off base? Not really. Why not dissect the dives that nothing went wrong,but were begging for a problem as seem in the first example. I recall the number of times that I have seen people "hook up" for a dive on the other side of the Heinkel or some distant location in JB,having no diving experience as team,but just a chance encounter to dive together. The predive planning is I got backgas to X pressure,and stage tank to X pressure-lets go dive. They complete the dive,and everything is successful so it reinforces the premise that this is okay and safe. But now is the time to dissect all the things that can go wrong,and what needs to be done to make this a safe dive. Looking at things like gas planning to start this thread,and even Rob's suggestion of spare scooters are the tip of the ice berg of solutions.
"Not all change is improvement...but all improvement is change" Donald Berwick
That comes back to training. There's a bunch of things being taught and it's easy to end up with a group of divers where everyone isn't on the same page.
Now of you want to get into a fun discussion, throw safety bottles into the mix. Now it gets complicated.
No, simply because there are other things that can fail on the scooter too.
I don't know; I think more complacency and poor planning.
"Not all change is improvement...but all improvement is change" Donald Berwick
Agree mechanical things fail first,such as relays,pulleys and switches. Makos used to have the LED meter,which had a huge amount of variability ,but once you learned your specific scooter they were quite handy.
"Not all change is improvement...but all improvement is change" Donald Berwick
Led back then? That's cutting edge
Id be less interested in a gadget displaying battery life than in past application of the equipment. Very similar to the "math" of gas versus the "application" of gas usage.
As for gas planning, It is very dependent on the depth, distance and buddy arrangement. It seems that the more gas mixes you need the more scooters you need and the less conservative your gas planning becomes as you have more total gas rather than just bottom gas in the cave. Not to be confused with unsafe gas planning.
For example: single gas w/O2 deco and I understand not touching back gas and only using (even sacking) the stage (use 80cf and reserve 240ish cf for the entire dive); however, very difficult to plan to bring that much reserve gas to a Nest dive. So add a back up scooter and sufficient gas plus you have deco gas to assist your exit adding in a slight bit of conservatism/safety.
Bob
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