Wreck Diving

[TSandM]

A friend of mine, when I was first learning to dive, told me a horror story about being on a cleanup dive in a local site which is considered incredibly benign (max depth 35 feet) and is used for training and beginners. Viz is often very poor. She got separated from her buddy and t
angled in monofilament. She had to take off her BC to clear the entanglement, and surfaced with about 300 psi. (The buddy had never surfaced to look for her, and no one knew she was missing or having any problem.) It made a huge impression on me: Benign sites may not be, and entanglement can kill you in shallow water. I carry a cutting implement on every dive. (I used to carry a knife AND shears, but I haven't seen a net or fishing line on any dive in Puget Sound yet, so now I just carry my knife.)

As I've observed before, a lot of people don't consider the "what ifs".

 

[do it easy]

And the thing about the "what ifs" is that they will bite you exactly when you lose respect for them.

The only time that I've EVER had to actually shoot a bag, I had forgotten my spool on the boat. I did bring my SMB with me, but it did me no good without the spool.

 

[StreetDoctor]

We dove with 80 cu/ft tanks (Nitrox) and that 1200 psi wasn't the current pressure we had at the time of the incident. That was only an agreed pressure to start our ascent. I checked my dive computer log and I surfaced with 1000 psi. We spent 15 minutes on the wreck. Those where 3200 psi fills that we had. I bought 2 cylinders thinking we were going do to two dives but the captain pulled anchor and we went to Molasses Reef. So much for the $10 bottle of Nitrox...

The point I was trying to make is 1200 is no where near enough gas in an AL80 to complete your deep stop and safety stops if your buddy had an out of gas incident at the end of your dive. To be honest I don't think I'd even do a dive that deep with an AL80 since I've seen the light (been educated). Research turn pressures and I guarantee they will suprise you, I know I was pretty shocked. I'm diving the grove in a month and I'll be renting an HP100 to do it. Without doing the math I believe the turn pressure in an AL80 at 90' is around 2500psi. 2500psi for you and your buddy to breath off your tank and complete your stops and still have a small reserve. Someone correct me if I'm wrong here.

 

[theskull]

The point I was trying to make is 1200 is no where near enough gas in an AL80 to complete your deep stop and safety stops if your buddy had an out of gas incident at the end of your dive. To be honest I don't think I'd even do a dive that deep with an AL80 since I've seen the light (been educated). Research turn pressures and I guarantee they will suprise you, I know I was pretty shocked. I'm diving the grove in a month and I'll be renting an HP100 to do it. Without doing the math I believe the turn pressure in an AL80 at 90' is around 2500psi. 2500psi for you and your buddy to breath off your tank and complete your stops and still have a small reserve. Someone correct me if I'm wrong here.

You may be wrong here . . . then again, you still have very few dives and may go through your air much more quickly than you will once you gain more experience. Personally, I would be very comfortable calling the dive with 1000 psi in an Al 80.

If my buddy had an out of gas incident at that point (this is a recreational NDL dive) I would be skipping the deep stop (a nice luxury, but unnecessary) and proceed to the safety stop, where I would make as much of a 3-minute stop as was prudent given remaining gas supply.

theskull

 

[Divedoggie]

Why would your buddy have an OOA incident if the agreed turn pressure was 1200psi? Whoever gets down to 1200psi first controls the dive.
Anyway, its good that you had the knife, are paying attention down there, and are gaining more experience and seeking education.

 

[theskull]

Why would your buddy have an OOA incident if the agreed turn pressure was 1200psi? Whoever gets down to 1200psi first controls the dive.
Anyway, its good that you had the knife, are paying attention down there, and are gaining more experience and seeking education.

While it is unlikely in the warm Florida waters, it is possible that your buddy could have a freeflowing reg, which would rather quickly become an OOA incident. And, since this was an insta-buddy rather than a trusted regular partener, he could also neglect to monitor his pressure and suddenly notice that he was OOA.

theskull

 

[Gilldiver]

A friend of mine, when I was first learning to dive, told me a horror story about being on a cleanup dive in a local site which is considered incredibly benign (max depth 35 feet) and is used for training and beginners. Viz is often very poor. She got separated from her buddy and t
angled in monofilament. She had to take off her BC to clear the entanglement, and surfaced with about 300 psi. (The buddy had never surfaced to look for her, and no one knew she was missing or having any problem.) It made a huge impression on me: Benign sites may not be, and entanglement can kill you in shallow water. I carry a cutting implement on every dive. (I used to carry a knife AND shears, but I haven't seen a net or fishing line on any dive in Puget Sound yet, so now I just carry my knife.)

As I've observed before, a lot of people don't consider the "what ifs".

It is the mono you don't see that is the problem.

The other problem is that mono may have a few hooks at one end and off that hook may be some stainless steel leader. Just a few days ago a friend was clearing some line from the prop of another boat on the dock. In doing so he ended up getting a good sized hook right into his hand. Now he was all of 3 feet down but firmly hooked to the prop with a hook in his hand and a stainless steel leader wrapped around the prop. It took him about 10 minutes to saw through the leader and get free. Shears or nip would have made it much easier.

If there is any chance of fishing in the area, take a knife and shears.

 

[ScubaSteve]

I am a little confused by this. How was it that you had to adjust your dive because of the limitation in doing a deep dive on air while you were diving Nitrox? Nitrox has a shallower MOD than air does (especially the higher mixes) so perhaps you can explain this. And, with limited number of dives, I somehow doubt advanced gas training has occured beyond the basic Nitrox course (this is all I have so this is neither a shot nor criticism )

I will say we all came to an agreement to start our ascent at 1200 lbs and this bought me time....yes choosing partners will become a priority of mine.

I had on a previous dive during the same trip buddied with an older gentleman (weekend diver) that did a deep dive on air and had to watch him also (I had Nitrox). I'm not a babysitter and will select very carefully from now on who I dive with. That limited me to his limits and had to recalculate my dive according to his time. What a waste of Nitrox....:depressed:

Did I save the kids life? I don't know and I'm very happy I didn't have to find out a differant way. Yes it is important to have the proper tools of the "trade".

 

[sunapeebob]

My son and I dive with both knife and shears for the steel leader in the water. In fact, my son has two knives, one on each side of the BC so that he can reach them with either hand. If we are diving wrecks, we also use leg knives. It sounds like a lot, until you need it. We have used the shears and knives on mono on wrecks as well as steel leaders. We actually freed a bass in a fresh water dive that had gotten stuck on an old wooden boat with the mono and hook. It was a little weird to gently hold the bass and then cut it free right at the mouth. I views the cutting implements much like lights - you can't really have too many and redundancy is good.

Bob

 

[DiverRider]

I just wanted to mention that you may not be able to tell from looking at them if they have a cutting tool or not, since it or other safety gear may be in pockets.

For example, I have shears in one of my pockets, but you would not know this unless you were my buddy or they came out for some reason. I and my usual buddies have shears in our pockets (which, BTW, I believe are safer than knives underwater), as well as an SMB, spare mask, slate and pocket snorkel. You would not be able to tell any of this from looking - you would only see the whistle and Scuba Alert on the hose.

Valid point, I did see some divers with pockets, side bags and these were the very experienced ones. It was noticeable they had all the backup equipment needed for penetration dives and the like. A lot of people had rental gear....it's pretty noticeable on dive shop boats.
I do like the idea of having shears and thank you, I agree that in most cases that would be a safer option. I took notice, in retrospect, that while I had the knife out of my holder I was distracted by the safety aspect of it being in my hand while untangling the mess. There is a very small margin of error while working close to another diver underwater with a knife exposed.