Lessons Wreck Penetration

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I just ran into this fine thread, and it has me thinking, especially the first few posts about zero visibility. We don't have a lot of what we consider good OW training sites near us, but I realized that this may be an advantage.

One of the popular sites is a shallow reservoir that has pretty bad visibility to begin with. To make it remotely interesting, people have placed all sorts of crap on the bottom--toilets, a shopping cart, an old rowboat, a fire hydrant, etc. They are connected by lines inches above the silt. When open water classes are held there, students are sent along those lines, and most of them rototill the bottom as they go. I try to force my students to show better buoyancy than that, but it can still be quite a silt storm.

It just dawned on me that a weekend when there are lots of OW divers there would be a perfect time for a zero visibility workshop. The divers would be following lines in little to no visibility, and in the worst case scenario, the surface is just a short haul above them. I could even make a challenge for them to map the artifacts.

Hmmmm.
 
There are a plenty of divers on this board with lots of time on wrecks all over the world. What have you learned beyond silt-outs, gas planning, and using a reel to make wreck diving safer and more interesting?

What advice would you give someone to be better prepared for a wreck class, or to become a better wreck diver?
The Truk Lagoon Wrecks planning dilemma:

Especially for the GUE Cave and UTD Wreck-trained Divers as to overhead protocol: you will either be with a dive guide who will lead your team on traverses through the shipwrecks' cargo holds, superstructures & engine rooms etc. --all without running line-- or choose to run a reel-line & egress out on reel-line without using a leading dive guide.

The advantage of running a reel-line is of course safety & standard operating overhead procedure as trained; the disadvantage is that you won't have as much bottom time to fully explore the wreck than if you did a through-and-through traverse. In other words, the dilemma will be whether to do "Trust-Me" dives with a Dive Guide or not. . .

The Trust-Me Dive goes both ways in Truk --the Guide is vetting you on the initial easy checkout dives, making sure of your general trim & kicking technique as well as your aptitude & temperament for wreck diving. He's gotta be sure that you won't panic when the rust & silt starts "percolating" all around you. . .
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There will be times where you will be in a tight engine or crew space in a near silt-out; or momentarily lose sight of the Guide around a corner corridor or up through a vertical gangway; or going thru 'Black Hole' caverns -burned out blackened ship spaces that totally suck-out the illumination from your canister light (and where the worst of all zero-viz conditions can occur -"Black Ash Silt-outs"). You have to trust that the Guide knows where you are at all times as well as all wreck egress pathways, and the Guide has to know that you won't make a potential emergency contingency worse by freaking out. . .

A compromise best solution is to have a "Pathfinder Team" --that is a team laying line with a Dive Guide in front leading a traverse through the wreck; and then having other teams come in later following that line to video/take pictures/sight see etc. --and then finally later a "Clean-Up Team" to reel-in the guideline, while traversing back in the opposite direction and winding-up reel-line. . .
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Modified Thirds,Turn-Around Pressure and Learning How to Do Lost Buddy Search Gas Availability Calculations. . .

Suppose you originally planned a wreck penetration starting with 200 bar at the entrance, with an openwater Rock Bottom of 50 bar. 200 minus 50 bar equals 150 bar usable for the penetration --Modified Thirds of this value is 50 bar (one-third of 150 equals 50), so you would turn-around for egress when you consume 50 bar of gas with an actual SPG reading of 150 bar. If you needed to do a gas-sharing emergency egress with your buddy at this point, you would both need a total shared 100 bar to get out of the wreck, plus another shared 50 bar Rock Bottom remaining to get both of you to the surface (or your Oxygen deco bottle stop of 6m).

Lets say you used up 30 bar already getting to the entrance of the wreck for a total of 170 bar pressure available --can you quickly recalculate Modified-Thirds?

No problem with bar pressure metrics: 170 bar minus 50 bar Rock Bottom yields 120 bar usable for the penentration; One-Third of 120 bar is 40 bar which is your new Modified Thirds turn pressure value. Therefore you would turn the dive when you consume 40 bar for an actual turn pressure SPG reading of 130 bar (170 bar minus 40 bar equals the actual turn pressure SPG reading of 130 bar).

What if you lose your buddy at this instance, at the farthest distance inside the overhead your Modified Thirds value allows? How do you calculate the amount of gas to do a Lost Buddy Search?

Easy! At your turn around pressure reading of 130 bar on the SPG, simply add your Rock Bottom value to your Modified Thirds value (50 bar Rock Bottom plus 40 bar Modified Thirds equals 90 bar); Put a line-arrow pointing the way out on your mainline that you've laid, and take reference note of where you are inside the overhead at that exact point as well. Now go and search for your buddy with the understanding that you must be back at this line-arrow marker by the time your SPG reads this actual value (90 bar). So you would have from 130 bar down to 90 bar reading on your SPG, or 40 bar delta of gas to search for your buddy --if you were to do a straight line search down a long corridor inside the wreck for example, tactically you should use 20 bar out and 20 bar back to your line-arrow marker for a delta of 40 bar, and an actual end of search SPG reading of 90 bar-- you must start your egress whether you found your buddy or not when you use up this 40 bar delta of gas, at the line arrow marker, with the actual 90 bar final reading on your SPG.

At any point before your Modified Thirds turn pressure, for a lost buddy search, the final egress pressure is figured just by adding your Rock Bottom value to the amount of gas you've consumed on the penetration up to that point --for example you start with 170 bar on your SPG and you lose your buddy with 140 bar SPG reading for a delta consumption of 30 bar. 50 bar Rock Bottom plus delta consumption of 30 bar equals 80 bar. Drop a line arrow, and now you've got from 140 bar down to 80 bar (a tactical delta search pressure of 60 bar) to look for your buddy, and be back to your line arrow to egress smartly when your SPG reads 80 bar.

At any point after your Modified Thirds turn pressure, all you need to do to figure out a final egress pressure for a lost buddy search is to subtract your Modified Thirds value from your actual pressure reading, and place a line-arrow pointing out at this point on your mainline. For example, if you're egressing and you lose your buddy with 120 bar actual reading on your SPG: Subtract the Modified Thirds value of 40 bar from 120 bar -which equals 80 bar- and it is this actual reading that you must have on your SPG when you get back to your line arrow to successfully exit the wreck with all your Rock Bottom still available to reach the surface. Another way of looking at this, at your nominal turn-around point & afterward on egress, the amount of gas tactically available for a lost buddy search is always just your Modified Thirds value --in this case 40 bar.

Remember that on a lost buddy search, you will deliberately encroach and use up the Modified Thirds Reserve Value needed for an emergency gas-sharing egress contingency (and possibly use up some amount of Rock Bottom as well) --in other words, if you do find your lost buddy and worst of all worst scenarios he happens to be out-of-gas in a silt-out . . .well dea ex machina. I hope you're in a 3-person Team, somehow make it out and run into other divers on the outside who can donate gas & assist. . .

[Note: the above gas plan is taken from wreck penetration dives on the HMCS Yukon (San Diego); USS New York (Subic Bay Philippines); HMAS Perth/USS Houston (Sunda Strait Indonesia); and various wrecks in Truk Lagoon. Depth 30m using twin 11L/bar tanks (double AL80's) and Oxygen deco.]
 
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The Truk Lagoon Wrecks planning dilemma:...

I was in Truk a week after the 70th anniversary of Operation Hailstone, which reminded me of the story that started the thread. I think the issue in Truk is less about gas planning and trust-me dives than recognizing the structural problems.

At least aboard the Odyssey, the crew knows their way around the wrecks really well. However, several times after some rudimentary structural observations I found myself thinking "I would never send my brother in there and I ain't go'in in there". Most of these ships were over-due for the scrapper before they were sunk. Understandable during wartime, but not so great for divers after 70 years in shallow tropical water.

Don't get me wrong, there were plenty of spaces I explored, but there were some I found other things to look at. I was also declared "solo" so could meander at will without making guides concerned I was missing.
 
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Also structural issues due to fire, battle damage by bomb & torpedo detonations during the raid, as well as the stress of some wrecks laying in situ on their sides for the past 70 years. Superstructures are just shearing falling & collapsing away (Rio de Janeiro Maru, Yamagiri Maru, Heian Maru, Fumitzuki Destroyer, Kiyosumi Maru). According to the veteran dive guides at the Blue Lagoon Dive-ops, the wrecks will all be piles of unrecognizable rubble in ten years.
 
I just ran into this fine thread, and it has me thinking, especially the first few posts about zero visibility. We don't have a lot of what we consider good OW training sites near us, but I realized that this may be an advantage. ...//... It just dawned on me that a weekend when there are lots of OW divers there would be a perfect time for a zero visibility workshop. The divers would be following lines in little to no visibility, and in the worst case scenario, the surface is just a short haul above them. I could even make a challenge for them to map the artifacts.

Hmmmm.

-and running shortcuts with compass and reel. You just described my most favorite quarry, Willow Springs. "Night diving all day long" -you can buy that T-shirt. :wink:
 
… According to the veteran dive guides at the Blue Lagoon Dive-ops, the wrecks will all be piles of unrecognizable rubble in ten years.

That fits with my estimates. You have to wonder what will happen to the Chuuk economy when that happens. I didn't see any indication that there was anything else driving their economy.

---------- Post added June 27th, 2014 at 08:29 PM ----------

... It just dawned on me that a weekend when there are lots of OW divers there would be a perfect time for a zero visibility workshop...

Great idea, but take baby steps in very shallow water.

Another Sea Story:
There was a submarine qualified diver trainee in the class ahead of me in Second Class Diving School. After Scuba school, which was by far the most physically demanding, they began training in the Mark V helmet and dress. The first day they strap you into a hat with the small windows blacked-out and have you dive in an 8-10' deep tank. He couldn't take it before he even got to the ladder. I would never have believed that a diesel submarine sailor with his Dolphins would be claustrophobic. I guess that is why they blacked out the windows.

Ask any commercial or military diver, being completely comfortable in zero visibility makes you a better diver even in crystal clear water. You really do think differently after that.
 
I didn't see any indication that there was anything else driving their economy.
When I was there we did a tour of what was the main island in the Japanese days. What poverty! The island had had no electricity for three years at that point because a landslide had taken out its only generator, and they were waiting for the funds to come through from FEMA to fix it. The schools were in old Japanese military buildings, and the only changes to the buildings from those days were newer roofs. I reached through a gaping hole in a rusted screened window to take a picture of a 12th grade classroom--a circle of rusted desks and one book shelf with one book. Those are our (USA) tax dollars at work.

At one point one of the older people said that when the Japanese were in charge, it was terrible because they beat and killed so many of us, but at least we had decent roads and buildings.
 
That fits with my estimates. You have to wonder what will happen to the Chuuk economy when that happens. I didn’t see any indication that there was anything else driving their economy.

Chuuk FSM (as well as The Marshall Islands & Palau) has a Compact of Free Association with the US (with the use of Truk Lagoon as a potential future quick staging and back-up base for our inevitable war with China/N. Korea). The U.S. treats these nations uniquely by giving them access to many U.S. domestic programs. The wikipedia page states, ". . .in 2008 the Federated States of Micronesia had a higher per-capita [military] enlistment rate than any U.S. state, and had more than five times the national per-capita average of casualties in Iraq and Afghanistan.[7]"

Great idea, but take baby steps in very shallow water.

Another Sea Story:
There was a submarine qualified diver trainee in the class ahead of me in Second Class Diving School. After Scuba school, which was by far the most physically demanding, they began training in the Mark V helmet and dress. The first day they strap you into a hat with the small windows blacked-out and have you dive in an 8-10' deep tank. He couldn’t take it before he even got to the ladder. I would never have believed that a diesel submarine sailor with his Dolphins would be claustrophobic. I guess that is why they blacked out the windows.

Ask any commercial or military diver, being completely comfortable in zero visibility makes you a better diver even in crystal clear water. You really do think differently after that.
The best silt-out training apparatus for wreck penetration diving IMO/IME, is in Subic Bay Philippines: an old wide-body fuselage cargo jet (a crashed landing & junked DC-10? -when FedEx used to fly from there) sunk in barely 6m of murky water -tons of ash run-off silt from the 1991 eruption of Mt Pinatubo- in front of Vasco's Resort/Hotel/Restaurant. In my 2006 technical wreck class with Techasia, we spent nearly 90min on Eanx32 inside that fuselage practicing laying line & doing 3-man team drills while the Instructor intentionally kicked-up the silt for a real zero-viz training environment. (Instructor said he still could "see" the glow of primary lights & monitor our progress as he floated along above us. . .)
 
... The best silt-out training apparatus for wreck penetration diving IMO/IME, is in Subic Bay Philippines: an old wide-body fuselage cargo jet...

I have been thinking about this. Black water is black water, but it is probably better to train in areas you normally dive. If that is tropical then great, but not so good for New England, Great Lakes, or North Sea wreck divers. You want all the normal stressors plus pitch-black water and feeling alone. By the same token, adding cold and sloppy sea states serves little purpose if that isn't similar to where you are diving wrecks.
 
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There are a lot of threads that discuss wreck diving courses, but not many that help you figure out when to take them.

In My Opinion:
Even if you have been fascinated by wrecks since learning to walk, I suggest making some wreck dives before taking any course. Just don't penetrate farther than you can back out and learn all you can from the outside.

Ideally start on purpose-sunk wrecks. They have been cleared of most hazards, have great access, excellent dive briefings, have guides that really know the wreck, and are usually in very nice diving conditions. You can also learn a great deal from others onboard. All this will make you far better equipped to determine how much training you want and how to find a good instructor. It will also significantly increase how much you absorb and retain during the course.

If you are still interested, then map-out your plan for more training. I emphasize "if" because you may discover that staying outside on easy wrecks is all you care about or that wreck diving isn't what you imagined.

Courses and Training
Obviously I am a big proponent of mastering black water, but mastering soft overheads is also wise before getting serious about penetration dives (hard overhead). I would encourage that you consider these courses before any serious wreck classes:
  • Nitrox and probably Advanced Nitrox
  • Solo -- solo partly because you can find yourself alone, but also for training in redundant gas and recognizing hazards
  • Decompression -- soft overheads
  • Boating Safety
Virtually all wreck diving is off a boat. I have only seen a few authors that even mention the importance of seamanship. You not only want to gain this knowledge for your own safety at sea, but it is invaluable for researching and understanding wrecks. I also encourage you to take the wreck class(es) where you intend to dive. Florida is really nice, but not if you plan to normally dive a drysuit in poor visibility. There are endless subtle things you will pick up even if they aren't specifically mentioned in class.

Choosing an Instructor
Finding an instructor with a good résumé is only step one. Take the time to meet them (interview really). We all have years of finely-honed skills for this — unless maybe if you were entirely home-schooled.
  • Do you respect them?
  • Does the instructor seem like s/he respected you?
  • Can you relate to them?
  • Did s/he explain your questions beyond saying that it will be covered in class?
  • Were they willing to say things like "I don't know" or "I never came across that" rather than obfuscate or brush you off?
You are a customer after all. Here are some threads on Scubaboard that may also provide some insight.

http://www.scubaboard.com/forums/ad...7-what-did-you-learn-wreck-diving-course.html

http://www.scubaboard.com/forums/ad...ons/352385-padi-wreck-diver-course-worth.html

http://www.scubaboard.com/forums/ad...ons/441716-wreck-diving-course-questions.html

http://www.scubaboard.com/forums/wr...-advanced-wreck-diver-course-reflections.html

http://www.scubaboard.com/forums/wr...et-into-wreck-diving-what-pre-requisites.html
 
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