85 ft Dive on 13 ft Pony Almost Ends Badly

[Killerflyingbugs]

You know what else this video illustrates? There's a lot of people spewing nonsense when it comes to gear, etc. Like "you should go out and buy a 40 cu ft pony for divers doing 60 ft. dives or you're going to die."

Right.

 

[Johnoly]

Jeez, we dive with that Captain !! The video clearly shows who it is, but that's a popular wreck site with boats on top of it. No way should he have been powered up.
The captain needs to reach out to you and talk,,,I know it was a mistake but he still needs to call you. I've made mistakes and called folks to apologize when I've crowded a site or dropped on their line,,,he needs to call and make it right.

Being a great captain is watching bubbles, and also the shape of the bubble patterns on the surface to know what's going on underwater. Not idling, is not right.
P.S. Don't blame Dumpster diver if he does get a call and then deletes this thread, it's his choice.

 

[dumpsterDiver]

John:

I don't think the capt has any idea it was me and I don't expect a phone call or anything else. Thank goodness it was a non-event and I assume it probably scared him more than me, at least afterwards.

I had no smb, so I really can't cast too much blame. He was momentarily careless, I've seen out right willful recklessness in one particular operator in the past and I did follow up and take a little time out of my day to make sure he knew who I was and what actions I intended to follow if the behavior was ever repeated.

This was just an unfortunate situation which I happened to capture on my camera. My mom prays for us a lot; she probably doesn't realize how effective it really is.

 

[eelnoraa]

Wow, dumpster. You ought to be careful. Your near miss situation seems to arise often these days. You are much more experienced and better diver than I am, I am not critizing you in any mean. I am concern. Dive safe. I enjoy your post tho.

 

[barth]

You're funny.

I'd say the same thing if it were you or anyone else who I've developed a relationship with on here.

But you want to know something? Jim, has continuously reached out to me pubIicly and privately giving me advice and answering my questions. He's probably had more impact on my diving than anyone else on here. So yeah, I would be sad if he freaking got hit by a boat before I ever had the opportunity to buy him a beer.

And while the opportunity hasn't presented itself yet, guess who would be the first person I'll call when I finally get down to S. Florida for some diving? And likewise he knows he has a place to crash over here in West Florida for some diving.

You know what else this video illustrates? There's a lot of people spewing nonsense when it comes to gear, etc. Like "you should go out and buy a 40 cu ft pony for divers doing 60 ft. dives or you're going to die."

It shows you you don't need a ponybottle or spareair.

A single tank and single valve is enough when doing dives in the range from 0-30 m or 0-100 feet.

 

[dumpsterDiver]

It shows you you don't need a ponybottle or spareair.

A single tank and single valve is enough when doing dives in the range from 0-30 m or 0-100 feet.

I wouldn't agree that this video necessarily supports that conclusion. I pretty much always take redundancy when scuba diving over 60 feet.. except in situations like this where we are snorkeling and and i need to cheat a little to get a shaft or a fish (or a weightbelt).

If the regulator instantly stopped working completely on that dive, I am pretty confident I could drop the pony and my weighbelt(s) and since I am not encumbered by any bulky scuba gear, I could probably make a swimming and buoyant ascent in 45 seconds or so -- but I would not be happy about it.

 

[HalcyonDaze]

I wouldn't agree that this video necessarily supports that conclusion. I pretty much always take redundancy when scuba diving over 60 feet.. except in situations like this where we are snorkeling and and i need to cheat a little to get a shaft or a fish (or a weightbelt).

If the regulator instantly stopped working completely on that dive, I am pretty confident I could drop the pony and my weighbelt(s) and since I am not encumbered by any bulky scuba gear, I could probably make a swimming and buoyant ascent in 45 seconds or so -- but I would not be happy about it.

Yep, better to have a margin for error in emergencies. Still an illustrative example of how a small backup tank can buy you a lot of time - this is actually a pretty timely post for me; as stated in another thread I've been looking into getting a pony bottle and yes, I was reading a number of posts that were pointing me towards bigger tanks (the one time I have used a pony, it was the 30s we have at work to comply with Army Corps of Engineers diving regulations). Having read this I might either get a 13 myself or go a bit more conservative with one size up.

And yes, nearly getting whacked by a boat is scary. I almost saw it happen once during my Southern California days; I tagged along with a friend who was helping one of his Cal State Northridge buddies collect fish for gonad samples near San Onofree. I was on the boat, anchored with the dive flag up, while the two of them were freediving and an outboard came zipping right into the kelp bed towards where I had last seen one guy go under. I think the other boat saw me waving the dive flag like I was at the Indy 500 and pointing at the water in front of him because I saw him slow and drop off plane; the CSU student popped up in front of him. I was having visions of chopped meat and tourniquets flashing through my mind until I heard the angry torrent of obscenities coming from the water; he had pushed off the side of the hull and gotten clear.

 

[Beau640]

This will derail the post slightly but I'm seeing some things in here that I feel need a little clarification. Divers should not be taking away from this that a 13cf pony is suitable for everyone for deep dives.

To figure out what size cylinder you should be carrying for reserve air, you need to know how much air you're going to use getting from your depth back to the surface. If you know your SAC rate and convert it into cubic feet/minute, you can use that to guesstimate how large of a cylinder you will need.

Let's say an average diver is using approx 0.6-0.7 cuft/minute at the surface. Under distress and in an emergency situation switching over to reserve air, that rate could increase to 1 cuft/minute. However, this is the rate you would be using gas at the surface. This increases depending on how deep you go (multiplied by the atm of depth you're at).

Let's say you plan to go 33 ft deep. Sh*t hits the fan. You switch to your reserve tank. You have 13cuft of air in that tank. You are now 2atm deep. For simplicity of calculation, assume your ascent uses as much gas as your deepest depth, and then calculate the amount you would then use at your safety stop. You will now burn through that tank in ~23 minutes (1 cuft per minute x 2atm = 2 cuft/min. 1 minute to ascend to safety stop so 2 cuft used. safety stop gas use ~0.5cuft / minute. 11cuft remaning/0.5cuft used per minute at stop= 22 minutes of gas at 15ft + 1 minute used at ascent = 23 minutes total). Plenty of air in a 13 cuft pony for that dive

However if you are going 66 ft deep, now you only have ~16 minutes of gas (1 cuft per minute x 3atm = 3 cuft/min. 2 minute to ascend to safety stop so 6 cuft used. safety stop gas use ~0.5cuft / minute. 7cuft remaning/0.5cuft used per minute at stop= 14 minutes of gas at 15ft + 2 minute used at ascent = 16 minutes total) Still enough since you should only need 2 minutes to ascend and 3 minutes at a stop.

But now let's talk about going even deeper. 99 ft on a deep dive. You're only going to have ~5 minutes of gas (1 cuft per minute x 4atm = 4 cuft/min. 3 minute to ascend to safety stop so 12 cuft used. safety stop gas use ~0.5cuft / minute. 1cuft remaning/0.5cuft used per minute at stop= 2 minutes of gas at 15ft + 3 minute used at ascent = 5 minutes total). Not enough to ascend slowly and complete a safety stop. You're going to suck that tank dry. And even with rough calculations and assuming you're going to have more air than this, you still barely have enough and are running the risk of running out.

Now these are rough calculations because in reality as you ascend, your depth changes and your gas use would lesson as you ascend. So these calculations are extremely conservative. However at the same time, you want to make sure you're going to have enough gas in your tank when you're working hard to breathe and you don't want to be sucking that reserve tank down to 0.

In reality, for dives <60 ft you can easily get away with 13cuft. However, it would be a better idea in my opinion to have something more like a 30 cuft tank which would also be useful if you need it for deeper dives in the future and to have a higher margin of safety for the shallow dives. The last thing I want to worry about when something goes wrong under water is if I have enough air in my reserve tank.

 

[oldschoolto]

If you are solo diving and going in the 100+ depth... You should be able to handle a major problem without your SAC going through the roof.. If you're a person that can't keep your $hit together when the $hit hits the fan... YOU SHOULD NOT BE THERE !!!!!

Jim..

 

[scubadada]

Beau640

Nothing like an inexperienced armchair quarterback.

Good diving, Craig