Question for divers

[HeinSdL]

So the latest theory on how the pipeline in the Baltic Sea was blown up revolves around the charter of a Bavaria 50.

https://www.theguardian.com/world/20...pelines-report

Question for those in the know - is it realistic to dive to 80m depths installing two tons worth of explosives using this type/size of yacht as a platform? It seems far fetched to me but just trying to decide how far fetched exactly. Better not make this thread into a political thing though.

[LakeSuperior]

The short answer is definately yes! It would not even be a much of a challenge with a little planning for a couple guys that know what they're doing.

Tech divers have been routinely diving to 80m since the 1980s.

If the mission was carried out on the sailboat a series of dives using closed-circuit rebreathers on trimix would be likely. My guess is bottom time would be limited by water temperature. With heated dry suits realistically a series of one hour bottom time dives were used. The explosives could simply lowered to the site in easily manageable package sizes, moved into position, and wired up.

[fstbttms]

Originally Posted by HeinSdL

So the latest theory on how the pipeline in the Baltic Sea was blown up revolves around the charter of a Bavaria 50.

https://www.theguardian.com/world/20...pelines-report

Question for those in the know - is it realistic to dive to 80m depths installing two tons worth of explosives using this type/size of yacht as a platform? It seems far fetched to me but just trying to decide how far fetched exactly. Better not make this thread into a political thing though.

The article indicates that the Bavaria 50 was not a suitable boat- these dives required a bell and and that boat could not have carried one. If indeed the Bavaria 50 was involved at all, a second vessel would likely have been needed, as the article states.

[Anders]

80m is easily done with hypoxic trimix but getting all the explosives where it's needed is likely to be a bit more difficult.

[flightlead404]

Originally Posted by Anders

80m is easily done with hypoxic trimix but getting all the explosives where it's needed is likely to be a bit more difficult.

I’ve certainly done deeper divers into water probably as cold on open circuit (325 feet fresh water, mid 30 degree f temp deeper than 150’) but it’s a long dive, mostly from the deco time. As I recall it always something like a 5 hour dive for 20 mins on the bottom.

Depending on the profile of the dive the rebreather may decrease deco time since it can adjust the mix you are breathing dynamically to maximize your partial pressure of O2 and therefor reduce the partial pressure of inert gasses. There are limitations, a PPO2 > 1.6 will render you unconscious pretty quickly. On a square profile dive (down, stay at a single depth, ascend) it may have less of an impact if the diver open circuit diver can optimize mixes.

Of course a CCR diver still has to carry all the bail out bottles planning for a worst case CCR failure, which is just as you reach the end of your planned bottom time.

[jordanbigel]

Originally Posted by HeinSdL

So the latest theory on how the pipeline in the Baltic Sea was blown up revolves around the charter of a Bavaria 50.

https://www.theguardian.com/world/20...pelines-report

Question for those in the know - is it realistic to dive to 80m depths installing two tons worth of explosives using this type/size of yacht as a platform? It seems far fetched to me but just trying to decide how far fetched exactly. Better not make this thread into a political thing though.

I don't see where you get "two tons of explosives" - this is what I read:

...the amount of explosives used in the sabotage attacks, estimated to be several hundred kilograms...

So, generously assuming "several hundred" means 600k that gives us 1,320lbs - two tons would be 4,000lbs. I know nothing about explosives, but it sounds to me like they could get the job done with a lot less bang, I mean its just a pipe right?

I think a Bavaria 50 could easily carry that plus the 6 man crew, dive gear, etc., etc. - it would have been cramped to be sure, but the distance from Rostok to the site is short.

[MicHughV]

Just a thought....couldn't they have just lowered the explosives without diver assist. A good depth sounder can easily see what's on the bottom at 80M...250 odd feet.
Wouldn't have to be a direct placement either, as the shock waves could probably cause the damage...much like submarine depth charges of bygone days.
No expert on the matter, just mulling over possibilities....
And why that location...???

[fstbttms]

Originally Posted by jordanbigel

I don't see where you get "two tons of explosives"

You didn’t read far enough:

“Some experts say up to 2,000kg would have been needed.”

[Scubaseas]

Originally Posted by flightlead404

I’ve certainly done deeper divers into water probably as cold on open circuit (325 feet fresh water, mid 30 degree f temp deeper than 150’) but it’s a long dive, mostly from the deco time. As I recall it always something like a 5 hour dive for 20 mins on the bottom.

Depending on the profile of the dive the rebreather may decrease deco time since it can adjust the mix you are breathing dynamically to maximize your partial pressure of O2 and therefor reduce the partial pressure of inert gasses. There are limitations, a PPO2 > 1.6 will render you unconscious pretty quickly. On a square profile dive (down, stay at a single depth, ascend) it may have less of an impact if the diver open circuit diver can optimize mixes.

Of course a CCR diver still has to carry all the bail out bottles planning for a worst case CCR failure, which is just as you reach the end of your planned bottom time.

Do your hang time on 80% O2 and you could cut that deco time in half at least. A good drysuit will work in 30* water. Either rebreather or Stargon at depth. It's definitely doable with off the shelf SCUBA gear but the bear would be moving the explosives. Easier to do this operation with a ROV or submersible.

[team karst]

I dove under ice wearing a US Army dry suit. Dry gloves, latex hood over neoprene, the works. Even tried chemical hand and feet warmers. I was only good for 20 minutes, and then my hands felt like fire. I cant take cold

[jordanbigel]

Originally Posted by fstbttms

You didn’t read far enough:

“Some experts say up to 2,000kg would have been needed.”

Oops.

[skipperpete]

I don’t have any experience with explosives other than as a spectator but I was in Sydney anchored near cottage point when an under water explosives expert demolished the remaining concrete structures at Illawong bay, it took a lot of time and ordnance to reduce that concrete to rubble. Later, much later, I was at Mourilyan harbour when contractors were engaged to blast a deeper passage through the entrance .....and that was a lot of tons of explosive for practically no depth gain so the dredge crane that dug the Sydney harbour tunnel trench was put on site to mechanically do what explosives failed to accomplish despite weeks of spectacular water plumes.
Apparently correct placement is very important.

[Scubaseas]

And yet you can take out a tank with a single shoulder fired RPG. How big of a shaped charge would you really need to punch a hole in a pipe? Or how many tank mines would it take? 80m ain't that deep. You really don't need a deco bell. You can bounce dive to that depth on mixed gas and have a very short decompression time, especially if done on O2 rich gas at 30'. Or do it on a rebreather.

I want to know what kind of anchor they used.

[psk125]

The pipes involved are apparently made of steel more than an inch thick, which are then covered in concrete to weight them down. (Filled with gas they would tend to float, no?) You'd need more than a cherrybomb to knock a hole in them.

[fstbttms]

Originally Posted by psk125

The pipes involved are apparently made of steel more than an inch thick, which are then covered in concrete to weight them down. (Filled with gas they would tend to float, no?) You'd need more than a cherrybomb to knock a hole in them.

Clearly. But apparently we have a whole lot of underwater demolition experts here