simple scuba setup for emergency.

[Art]

Originally Posted by Art

Read Post #85 - - - For Full Story of What Art Commented

I strongly recommend No Weights with such as I describe here.

You can easily go under boat and get to shaft/prop to cut off line. !

_________________________________________________________

You might be able to shaft is about 4ft down, about 6 ft back from the transom, inside a nozzle protected by rudder on ours.

Most definitely need lead and air on ours.

Lead was easy, enough to very slowly sink when breathing out
Enough to slowly float up when breathing in.

Air was easy, diy hookah with 240v oilfree compressor with 24litre tank and gauges, 50m of hose, reg and filter for about $200.

Happy to stand down there for a couple of hours working away given the right conditions.

* I have been snorkeling since I was a kid
Had studied various free online courses
Have a mate who is a padi instructor who reckons I was good to go.

Review Post #85 - - - For Full Story [see this page top]. Post #85 contains much more in-depth details regarding "Art" decades of first hand experience... than what is at at top of this page. There is way much more to review than the short quote placed above.

 

[Mako]

if you are going to do it and use weights perhaps ankle weights?

As a Sicilian I can tell you these are very popular [emoji3]

 

[SoWhat]

Originally Posted by Art
I strongly recommend No Weights with such as I describe here.
You can easily go under boat and get to shaft/prop to cut off line.

Physically impossible. My props are 3' down and 3' back. With a wet suit on you would diving like a shore duck. Head down rear up. In NE waters you need a wet suit. If you wear a wet suit you need weights. Cutting (sawing) a line off can take an hour. You will need Hookah, scuba, or some variant.
The stern will be crashing down from many feet. Helmet is a good idea. Keep all tools on a long lanyard around your neck. (Or keep a lot of duplicate tools on board)

In rough water you can't see the buoys until you are top of them, and at times you can't see them at all. Some type of shaft cutters are a good idea.

If you are caught on a pot warp and anchored to the bottom, once you cut free boat will accelerate. Quickly. You'd better be attached or have a long drag line.

 

[Benthic2]

I'm not an expert by any means,....
The absolute pressure difference in an ascent through 15' of water is the same no matter the depth .....

This is ABSOLUTELY WRONG, DANGEROUS, AND WILL KILL YOU !!!!!


If you do not know why, DO NOT USE COMPRESSED AIR !!!

 

[Takoradi]

Good one Mako!

 

[Stu-L]

My setup

I keep tanks on my boat and have a Hooka hose with regulator that connects to the tanks. I keep mask and fins and a spring wet suit aboard. I don't need weights as I am just below the water.

 

[Takoradi]

This is ABSOLUTELY WRONG, DANGEROUS, AND WILL KILL YOU !!!!!


If you do not know why, DO NOT USE COMPRESSED AIR !!!

Absolutely concur that this is absolutely wrong. There is a HUGE difference BECAUSE of the depth and this misunderstanding will get you killed.

 

[SoWhat]

This is ABSOLUTELY WRONG, DANGEROUS, AND WILL KILL YOU !!!!!
If you do not know why, DO NOT USE COMPRESSED AIR !!!

Boyles law was drilled into us. Volume of a gas is inversely proportional to the pressure. We were taught to follow our bubbles up and breathe normally but if you're out of air or drop your weight belt for an emergency ascent then you breathe out all the way up.

Not something I would want to try. Make a mistake and you will rupture the aveoli in your lungs. Won't end well. SCUBA or Hookah without training is extremely high risk. There are medical journal articles that have discussed cases of pulmonary barotrauma occurring from holding breath while ascending from a depth as shallow as 4 feet. Might not be fatal but...

 

[DDW]

This is ABSOLUTELY WRONG, DANGEROUS, AND WILL KILL YOU !!!!!


If you do not know why, DO NOT USE COMPRESSED AIR !!!

Well, the original post was confusing when it said:

The pressure gradient from 15 ft to the surface is the largest there is and has the highest risk from over-pressurization injuries.

The pressure gradient is constant wrt to depth in water from the surface to the bottom. The volume expansion in your lungs will differ in the two scenarios, and that may have been what was meant. The result may, or may not be different depending on how full your lungs are when the ascent begins. In either case, ascending 15' without exhaling may be a fatal idea.

 

[OldDan1943]

if you have been breathing compressed air, I dont care it is 5,10,15 ft or more, if you run out, force the air out (breath out as hard and fast as you can). of your lungs as you are ascending.
Did this in the US Navy a number of times from 33ft. You had to do this correctly if you expected to begin submarine school.

 

[ghost]

Just a quick FYI. The water temps in Puget Sound are about 44 - 68 degrees F, depending on time of year. If you haven't experienced trying to operate in cold water, you're in for a real treat. If you have then, you already know what to wear. I have watched newbies to the area, who think they know what cold water is (my BIL was one), jump into a river of glacier melt in nothing but shorts. They always need help getting out after only 30 seconds or so.

Typo? 52 is about the highest you will see and only if you have some stagnant water.

We used to swim in the Lewis river in SW Wash, during an 80 day, the river would still be cold enough to give hypothermia. But 30 seconds? Nah, we would be in for ten or fifteen minutes at a time. Would not want to do it now that I’m old, but I’ve swam in Puget Sound as an old guy for 15-20 minutes at a time, easily 30 minutes while working hard underwater. The worst is having to borrow a pair of shorts from your much bigger dock mate and tie them on with a 5/8 inch dock line when your new outboard becomes a submarine.

Anyway, cold temps are a huge factor, but best to be realistic. Get a wetsuit.

As for shallow water gas expansion, that is definitely a thing. It’s about how much the gas in your lungs is going to expand for the same 5-10 feet of ascent and the shallower you are, the relative expansion increases. Gas bubbles expand in relation to the pressure of the atmosphere at the surface(1 atmosphere). The pressure doubles at 33 feet, then triples at 66 feet etc. So in fact there is a greater expansion in shallow water than deeper water and yes it is true that breathing compressed air at 15 feet is dangerous, first because there is more gas expansion, second because that gas expansion at shallow depth makes it much more likely that a person may lose control of their buoyancy and find themselves on the surface before reacting. Newbs, by definition, do a poor job with gear selection and buoyancy control. It’s the hardest thing to learn.

 

[Wayne]

'Lo All,
Two Things:



1. Most of this was alluded to, but may not have been explained. DO NOT use an oil-lubricated compressor or a hose that has EVER been used on one for a hookah unit, as oil from the compressor can get into the lungs and cause a person to experience suffocation. I'm told that it doesn't take much oil. Always use a ceramic-type compressor (oil-free) with a filter and a hose that has never been used on an oil-lubricated compressor. The filter is used to prevent ceramic particles from the compressor getting into one's lungs.



2. I wrote about this experience years ago, but the short version is this: I had stopped to refuel at Indiantown Marina on the Okeechobee Waterway. A new boat was also there which was being delivered and had minimal crew. The boat had picked up a crab pot and the line was wrapped around one prop shaft. The second mate was an older guy who (I think) wanted to prove his worth so as to be hired again. He said he would dive under the boat and cut the line off. I told them that I had scuba gear on my boat and that I would remove the line. I rushed back to my boat and hurriedly got out the scuba gear and changed into my swimsuit. When I got back to the other boat, the second mate had gone under the boat, but had not come back up. As I felt around the bottom in zero visibility, I kept thinking of the huge 10-12' alligator (well, it looked that big) I had seen on the opposite bank. After a minute or so, I found the guy. He had apparently pushed off from the prop and hit his head on the rudder, knocking himself out. Unfortunately we were unable to resuscitate him.


Bottom line: Things can go sideways underwater in a heartbeat; know what you are doing and be properly trained and equipped.

 

[denverd0n]

1. Most of this was alluded to, but may not have been explained. DO NOT use an oil-lubricated compressor or a hose that has EVER been used on one for a hookah unit...

Yes, absolutely. The air compressor MUST be the oil-free type. Personally, I would go further on the air hose and insist on one that was rated for breathing air.

 

[Lamuncha]

Take the course

I would recommend a snorkel and wet suit with some weight. Even then you are at risk. SCUBA - not without training.
Quick example. I am certified, even so I violated a major rule and almost ain’t here to tell about it. Working on the bottom at maybe 30 feet my air started to pull harder, it was time to get out. But I didn’t. I knew the job was just about complete. So I pulled my reserve and continued - HUGE violation. At any rate the reserve suddenly pulled hard, I was almost out of air.
I shot toward the surface and about half way it ran out. I don’t recall the final 15 feet or the fear I had but just to ice the cake when I broke the surface I was in a three foot chop with white caps, gulped a few mouthfuls of sea water and pulled my inflatable vest. I think that is what ultimately saved me.
A lot of what you will learn in training about emergencies, panic, and carrying the correct and best equipment you can buy could save your life.
You are in a foreign environment where anything can happen.
It was a really dump-@ss move on my part violating a major rule but there you go.

 

[rgano]

Some years ago, I had a part-time commercial diver working on the boat to clean it up. His day job was as a Navy diver, and he told me he could set me up with a rig to do this stuff myself despite me no diving experience beyond what the Navy taught me as a salvage ship captain just so I knew how to manage the divers at arm's length. He bought a small (120 PSI or so max) electric, oil-less compressor at Lowes, attached 50-feet of food-grade hose to it with a second stage regulator, and threw in a weight belt all for around 150 bucks. He took the compressor to the US Navy Experimental Diving Command here in town and had it tested - it produced cleaner air than the compressors they had, but he told me if I ever experienced a headache to stop using it and blow all the way to the surface if air stopped.

I went out to the barrier island and anchored in about 8 feet of clear water over a white sand bottom and played with the weight belt until I had it right with and without wet suit. I planted my feet on the sand bottom and scrubbed the bottom of the boat with my long-handled brush. Did this for years, numerous times a year. NEVER had my head below about 6-8 feet. NEVER used in rough water. NEVER used in water colder than 65 F. NEVER used it in water deeper than about 12 feet. NEVER used it on a drifting boat when removing melted nylon line from others' prop shafts (only a couple of times). NEVER used it without the wife watching the compressor.

With a smaller vessel no longer kept in a wet slip, I no longer carry the rig aboard, but it's still in the tool shed. I could probably handle problems on this one with a snorkel and mask, but I now carry BoatUS towing insurance where I did not in the bigger, twin-engine boat.

 

[diver dave]

Gosh; I wonder where this thread would go if we started talking about actually dangerous diving...

 

[psneeld]

Gosh; I wonder where this thread would go if we started talking about actually dangerous diving...

Is there a topic on TF that won't get numerous posts on how dangerous that topic can be?

 

[Mako]

Good one Mako!

Tako I think you’re the only one who got it, gumba

 

[diver dave]

This is ABSOLUTELY WRONG, DANGEROUS, AND WILL KILL YOU !!!!!





If you do not know why, DO NOT USE COMPRESSED AIR !!!

Actually, DDW is correct about the pressure change. Its about 0.45psi per foot, about independent of depth. However, thats not the correct metric if barotrauma is the concern. Its percent change that the lungs will have an issue with. 33 ft to surface is a 100% change in pressure. 99 to 66 feet is much less %.

 

[SteveK]

if you have been breathing compressed air, I dont care it is 5,10,15 ft or more, if you run out, force the air out (breath out as hard and fast as you can). of your lungs as you are ascending.
Did this in the US Navy a number of times from 33ft. You had to do this correctly if you expected to begin submarine school.

I will add ascend at the same or less speed as the bubbles you made.

 

[MVDarlin]

Try a SNUBA set up. Tank stays on surface with a float and 40ft hose to regulator. Get a shorty suit.

 

[tiltrider1]

Try a SNUBA set up. Tank stays on surface with a float and 40ft hose to regulator. Get a shorty suit.

Really? You are going to recommend 40' of hose and a shorty to a guy with no training who will need to dive in 49 degree water. How long before his regulator freezes up? How long before he is so cold he can't pull himself out of the water?

I think there is a lot of bad advice on this thread.