Modern WisdomStephen McGinty - The World's Deepest Submarine Rescue | Modern Wisdom Podcast 351
CHAPTERS
- 0:01 – 0:28
A phone-box at 1,650 feet: what the rescue felt like
Stephen opens with a vivid analogy for being trapped in Pisces III: cramped, dark, oxygen-limited, and knowing rescue is days away. It establishes the stakes—survival depends on conserving air and staying calm while help mobilizes far above.
- •Phone-box-sized living space under immense pressure
- •Total darkness and “bleeding” oxygen once systems are compromised
- •Rescue is at least two days away due to distance and logistics
- •Core survival task: preserve oxygen and manage CO2
- 0:28 – 2:29
Why Pisces III was down there: protecting the new transatlantic cable
The incident happens during maintenance of the 1973 “CanSat” transatlantic telecom cable, laid ~150 miles off Cork. Pisces III’s job was to locate the cable and trench it so it would settle and be protected from fishing nets and trawlers.
- •Context: early-1970s high-tech transatlantic communications
- •Cable needed burying to prevent snagging/being hauled up by fishing gear
- •Work site: Atlantic seabed, far offshore from Ireland
- •Mission: dig trench so cable settles and can be covered by silt/sand
- 2:29 – 5:06
Who built and ran these mini-subs: Vickers Oceanics and Canadian pioneers
Stephen explains how Vickers Oceanics operated Pisces craft amid the North Sea oil boom, and how Canadian innovators like Alf Trice helped create practical commercial submersibles. He frames Pisces as both rugged and unusually “lucky,” even in early tests.
- •Vickers’ shift from major shipbuilding into miniature commercial subs
- •North Sea oil industry demand for underwater work platforms
- •Alf Trice’s salvage-diving background and push for practical subs
- •Pisces development and striking early test stories
- 5:06 – 6:02
Inside the Pisces III: tiny sphere, two men, and limited life support
Chris asks what Pisces III is like physically, and Stephen details the cramped interior and the scale of the pressure environment. The “phone box” analogy returns to emphasize how little space and margin for error the crew had.
- •Very compact internal diameter (roughly 5–6 feet)
- •Two-person occupancy with minimal room to move
- •Pressure context conveyed via Empire State Building/ocean analogy
- •Limited onboard resources and critical dependence on systems
- 6:02 – 10:24
The accident: a tow-rope mistake, flooded aft sphere, and uncontrolled plunge
After an overnight seabed shift digging the cable trench, Pisces III surfaces and is being towed back when a rope knots around an exposed bolt. The aft sphere floods, the locator buoy is already detached, and the sub sinks—first snagging at ~160 feet, then dropping all the way to the bottom when the rope snaps.
- •Launch/operations from the support vessel Vickers Voyager
- •Tow-rope knots around an uncovered bolt and pops the aft sphere open
- •Aft sphere floods, creating severe overweighting and a “butt-first” sink
- •Critical failure: locator buoy had been disconnected before the sinking
- •Crew braces for impact, stuffing rags in mouths to avoid biting tongues
- 10:24 – 13:14
Immediate survival problems on the seabed: CO2, batteries, and fire risk
On the bottom in pitch darkness, the crew’s first priority is assessing hull integrity and life support. Stephen explains that CO2 buildup is often the real killer, and that power/battery damage could also trigger a catastrophic onboard fire.
- •Check for cracks after the crash landing
- •CO2 management is as important as oxygen supply
- •Scrubber and oxygen “bleed” depend on batteries
- •Electrical damage could ignite—fire inside means no survival
- 13:14 – 17:18
Why rescue takes days: only a few craft can reach 1,650+ feet
Stephen outlines why immediate rescue is impossible: divers can’t reach that depth, so another deep-capable submersible must attach a lifting line. The viable assets are scattered—Pisces II (North Sea), Pisces V (Canada), and the U.S. Navy’s CURV—forcing an international scramble and transit back to Cork and out again.
- •Depth rules out diver-based rescue
- •Only certain submersibles can attach a lift line at depth
- •Key assets: Pisces II, Pisces V, and U.S. Navy CURV
- •Vickers Voyager must return to Cork to load gear/teams, leaving a marker ship behind
- •“Haystack vs needle” problem after losing the buoy
- 17:18 – 23:42
Life inside Pisces III: rationing air, underwater phone, and zero water
Back with the trapped crew, the focus becomes physiological and psychological endurance. They minimize movement and speech to stretch oxygen time, operate the scrubber on a timer (then push intervals), communicate via a static-filled underwater telephone, and cope with hunger, cold, and dehydration—licking condensation for moisture.
- •Oxygen duration: ~30–35 hours active vs ~65–70 hours if motionless/calm
- •Timer-based scrubber routine; they extend intervals to conserve resources
- •Underwater telephone communication; dolphins/porpoises interfere with messages
- •Minimal food and no drinking water; condensation used for hydration
- •Internal reconfiguration to reduce movement and energy expenditure
- 23:42 – 27:00
First rescue attempts fail: broken claw, buoyant rope, and searching blind by sonar
Once rescue craft arrive on scene, early dives are undermined by mechanical failures and the difficulty of locating Pisces III without its buoy. A buoyant rope increases tension with depth, ripping free and damaging the claw; subsequent searches rely on sonar pings that still leave them effectively “a mile away” in darkness.
- •Initial tow-out problems (engines failing) delay deployment
- •Buoyancy choice for rope backfires—tension increases with depth
- •Hook pulls free and mangles the claw; craft returns with leaks/tension issues
- •Search is primarily sonar-based; visual confirmation requires close approach
- •A sonar “ping” at long range doesn’t translate into easy rendezvous
- 27:00 – 32:17
Found—but not lifted: threading the needle, then losing the line and improvising
The Canadians finally locate Pisces III and attempt to secure the lift point—an operation Stephen compares to threading a needle in armor. The hook briefly holds, then slips out; they chase the drifting line and manage only a temporary attachment on a propeller grill, good for tracking but not for lifting. Meanwhile, life inside deteriorates (including the grim realities of toileting).
- •First illumination of light outside the porthole signals they’ve been found
- •Precision maneuvering to place hook into the lifting eye
- •One-in-a-thousand misfortune: hook slips out after seemingly locking
- •Rope recovered but only attached to a non-load-bearing propeller grill for guidance
- •Crew sanitation: plastic bag and sealed tin; compounding discomfort and stench
- 32:17 – 35:18
The ‘dirty dozen’ reinforcement and the toggle breakthrough amid storms
With oxygen running out and morale sagging, a fresh team is flown in and winched down onto a storm-tossed Voyager. Ted Carter and others help implement a new “toggle” lifting device—an umbrella-like T-bar that opens once inserted—created with rapid, analog-era engineering and fabrication under intense time pressure.
- •Leadership decision to inject fresh expertise as exhaustion sets in
- •Dangerous Sea King helicopter transfer onto a heaving ship in storm conditions
- •Toggle concept: insert then open to lock securely for lifting
- •Rapid design/manufacture culture—paper drawings, T-squares, same-day fabrication
- •Ted Carter’s key role in getting the first true lift line attached
- 35:18 – 37:55
CURV arrives and finally runs “like silk”: second line attached, lift begins
The U.S. Navy’s CURV system initially fails due to saltwater-contaminated circuits, costing precious hours. After rewiring, CURV performs smoothly, delivering another toggle and enabling a safer multi-line lift attempt—just as the crew is believed to have only hours (or less) of oxygen remaining.
- •CURV’s power-up failure from sea spray contamination; full rewiring required
- •Decision: one lift line is too risky—need redundancy
- •CURV piloted down with CCTV/remote control, executes clean placement of toggle
- •By morning, they estimate only a few hours of oxygen remain
- •Transition from repeated failures to a coordinated, multi-system lift attempt
- 37:55 – 42:32
The ascent is the worst part: violent lift, tangled systems, and diver attachment at 120 feet
As Pisces III is raised, storm-driven heave makes the sub surge up and down like a fish on a line, slamming the men around inside. Communication failures create confusion; CURV becomes entangled, and the team pauses near 120 feet to send divers to attach an additional line—an underwater ‘bucking bronco’ task requiring precise manual fastening.
- •Lift dynamics: ship heave causes repeated vertical jerks and pivoting
- •Crew fear: lines/toggles could fail and drop them again
- •Confused comms: crew yells to stop; surface misinterprets
- •CURV wraps around Pisces at one point, complicating the lift
- •Diver Bob Hanley secures an additional line with a carabiner-like mechanism
- 42:32 – 57:20
Surface doesn’t mean safe: hatch struggle, first argument, and ‘brotherhood of the sea’ aftermath
Even at the surface, they’re still sealed in the same air until the hatch opens; Mallinson struggles to get it free. After extraction, Stephen highlights the emotional impact on hardened crewmen and the broader international cooperation that made the rescue possible, then closes with what the survivors did next and where to find Stephen’s book.
- •Surface arrival still requires opening the hatch for fresh air
- •Lemonade ‘celebration’ only once they’re found; sandwich details revisited
- •First real argument: who exits first—complicated by Mallinson not being able to swim
- •Rescue’s emotional toll on the crews; many break down in tears
- •Post-rescue: both return to subs; Chapman builds a submarine rescue business; Stephen promotes ‘The Dive’
