Trapped in Cape Kinau Cave: The Dive of Preston Penny That Shook the Diving World
| Incident Location | Diver Full Name (Deceased) |
|---|---|
| USA, Hawaii, Maui, Cape Canow Cave | Preston Penny |
In 1985, a group of divers set out to explore the mysterious depths of Cape Kinau Cave, located off the coast of Maui, Hawaii. Armed with excitement, curiosity, and their diving gear, they descended into the dark, twisting passages beneath the ocean.
As they ventured deeper, the initial beauty of the cave quickly transformed into a trap. Visibility disappeared. Air supplies began to dwindle. Panic crept in. What happened next would alter the course of their dive—and their lives—forever.
The Allure of Cape Kinau Cave
A Hidden Gem in Aihihi-Kinau Natural Area Reserve
Cape Kinau Cave lies within the captivating Aihihi-Kinau Natural Area Reserve, a protected region on the southwest coast of Maui. Established in 1973, the reserve covers:
| Region Type | Area |
|---|---|
| Land | 1,238 acres |
| Ocean | 807 acres |
This stretch of land and sea runs along three miles of Maui’s rugged coastline and is known for its stunning and diverse environment. The terrain is primarily made up of pāhoehoe lava, formed from recent volcanic activity from the Haleakalā Volcano’s southwest rift zone.
Cape Kinau Cave is carved into this dramatic volcanic landscape, its entrance resting among jagged lava rock formations that extend into the ocean.
A Natural Underwater Labyrinth
The cave, formed by ancient lava flows, adds to the mystique of the area. Its proximity to the shoreline, surrounded by volcanic rock, makes it both visually stunning and potentially dangerous. This coastal environment, rich with marine biodiversity, is a hotspot for snorkeling and diving.
Beneath the surface, Cape Kinau Cave preserves geological secrets in its solidified lava walls. These structures are living relics of past eruptions, forming intricate underwater tunnels and chambers. The reserve also protects rare coral reef ecosystems and anchialine ponds, unique water pools connected to the ocean through underground tunnels.
The area’s significance lies in its role to preserve geological, cultural, and biological diversity—making it a treasure trove for explorers and researchers alike.
The Divers and Their Mission
The Morning of the Dive
On the morning of February 23rd, 1985, at 7:45 a.m., a group of eager divers gathered aboard Ed Robinson’s dive boat off the coast of Maui. The group consisted of:
- John Baird
- Tom Kan
- Masal Nan
- Preston Penny (37 years old at the time)
All four were certified in open water diving, but none had training in cave diving, which requires more advanced techniques and safety protocols.
Leadership and Preparation
The dive was led by Ed Robinson, a seasoned diving instructor who had explored Cape Kinau Cave before. Alongside him was his assistant Sue, who would serve as the group’s safety diver, tasked with watching over the divers and ensuring no one strayed.
The group reviewed the dive plan and chose Cape Kinau Cave as their first destination. The idea of diving into a submerged lava tube excited them—it was a stark contrast to the open-water dives they were familiar with.
They imagined navigating the cave with their diving masks and diving computers, capturing the experience on video. Each diver was equipped with one underwater light—an essential but insufficient tool for cave diving, where redundancy is critical.
Excitement vs. Preparedness
Although the group brimmed with excitement, their preparation did not match the cave’s risks. Cave diving is not simply deeper diving—it involves navigating tight, pitch-black spaces, where diving tanks, buoyancy, and lighting systems must be expertly managed.
Despite Robinson’s experience and knowledge of the cave’s layout, the rest of the group lacked the skills, experience, and extra diving equipment necessary for a safe dive.
The excitement of discovery overpowered concerns. They were drawn to the idea of venturing into a rarely explored, lava-formed underwater maze, feeling like pioneers of a hidden world.
Inside Cape Kinau Cave
Structure of the Cave
Divers familiar with Cape Kinau Cave describe a relatively simple but deceptive layout. The cave includes:
- One main corridor: the Trunk Passage, with entrances on both ends
- Three chambers off the main passage:
- Small Chamber
- Turtle Chamber
- Deep Chamber
The Trunk Passage was wide enough at one end to accommodate up to six divers swimming side by side. However, as the passage progressed, it narrowed significantly—especially at the entrance to the Deep Chamber.
Key Features and Hazards
- The Deep Chamber reached depths of 90 to 100 feet, accessible only through a tight, narrow passage.
- The floor of the cave was covered in fine silt, easily stirred by movement. If disturbed, the silt could cloud the water, causing zero visibility.
- A middle exit existed midway through the cave, where sunlight could filter in—but only if the diver was directly beneath it.
| Chamber | Depth | Description |
|---|---|---|
| Small Chamber | Moderate | Narrow, limited maneuverability |
| Turtle Chamber | Moderate | Named after sightings of sea turtles |
| Deep Chamber | 90–100 ft | Only accessible through a tight entry tunnel |
Navigating these chambers without training or proper communication greatly increased the risk of getting lost or disoriented.
Visibility and Disorientation Risks
Visibility in cave dives like this one is critical. The cave’s structure, silt, and confined spaces meant that even a small error could lead to complete disorientation. Without clear sightlines to exits or each other, divers could quickly lose their way.
While the middle exit provided a potential escape, it was unreliable—only visible under the right conditions, and easily missed if the water turned murky.
Setting Off Into the Unknown
With their diving suits sealed, lights tested, and tanks full, the group was ready. Sue, the safety diver, positioned herself behind the group to keep a watchful eye.
They descended into Cape Kinau Cave, eager to explore the mysterious underwater passages that had captured their imaginations. What they were about to experience was a combination of natural beauty, raw danger, and a true test of human endurance in one of nature’s most unforgiving environments.
The adventure had begun—but they had no idea how quickly things would spiral out of control.
A Dive Turns Dangerous
The dive began with careful preparation. Each diver carried an 80-cubic-foot cylinder, filled to 3,000 PSI—a standard air supply for open-water diving. However, in the context of cave diving, this was risky. The confined spaces and psychological stress demand additional air reserves.
Ed Robinson, an experienced diver, led the team while filming the dive. His assistant, Sue, took the role of safety diver, monitoring the group from the rear to ensure no one fell behind.
The Dive Plan
The dive plan was straightforward:
- Enter the cave
- Explore the chambers
- Stop at the middle exit for an air check
- Abort the dive if any diver’s air dropped below 1,500 PSI
At the middle exit, all divers still had more than 1,500 PSI, so the group agreed to proceed deeper into the cave.
A Descent into Chaos
As the divers reached the deep chamber—the lowest point in Cape Kinau Cave at nearly 100 feet—the dynamics changed. The deeper depth increased air consumption dramatically.
Tom Kan was the first to notice a problem. His diving computer showed only 600 PSI remaining. Alarmed, he signaled to Robinson to exit. Simultaneously, John Baird checked his gauge and discovered he too had dropped to 600 PSI.
Meanwhile, visibility deteriorated rapidly. The divers had stirred up fine silt from the cave floor, clouding the water and making navigation nearly impossible.
Robinson realized the gravity of the situation. With two divers running critically low on air and visibility collapsing, escape became the top priority.
A Frantic Escape
Robinson led Kan and Baird toward the third exit, the closest route out. But the exit path was narrow and clouded with silt, reducing visibility to near zero.
As they swam through the tight passage, Kan’s sonic alarm went off—a piercing warning that he was nearly out of air. In a panic, he signaled that he could no longer breathe.
Without hesitation, Robinson shared his air supply using his secondary regulator, helping Kan stay conscious. They pushed toward the surface together.
By the time they reached open water:
- Baird had only 100 PSI remaining
- Robinson and Kan had drained their tanks through emergency air-sharing
Disaster in the Deep Chamber
Inside the deep chamber, the situation grew worse. Visibility had plummeted to zero. The divers could no longer see each other—only faint glows from scattered diving lights remained.
Sue, maintaining her role as the safety diver, recognized the danger and signaled everyone to exit the chamber immediately.
- Masal Nan struggled at the narrow restriction between chambers but managed to escape
- Preston Penny, already in distress, required physical assistance from Sue, who pushed him through the tight passage
Both exited the deep chamber, and Sue and Nan successfully reached the middle exit. But Preston Penny never surfaced.
A Desperate Search
Back on the boat, Robinson quickly realized a diver was missing. Without hesitation, he grabbed an extra air cylinder and reentered the cave to search for Penny.
The cave was now a maze of darkness and confusion:
- Visibility was nearly nonexistent
- Tight restrictions made movement slow and difficult
Robinson felt his way through the silty water. After several tense minutes, he found Penny—but it was too late. He was unresponsive.
Robinson brought him to the surface, where rescue efforts failed. Penny had drowned, likely overwhelmed by the stress, physical limitations, and complete air depletion.
Postmortem: What Went Wrong
When Preston Penny was found, he still clutched:
- A camera in one hand
- A diving light in the other
His air tank was empty, his gear intact, and yet he had succumbed to the unforgiving environment of the cave. Even though visibility in that part of the cave was relatively good, it wasn’t enough to save him.
This tragic event highlighted numerous critical mistakes:
Air Management Failure
The team violated the fundamental rule of cave diving:
“Use one-third of your air to go in, one-third to come out, and keep one-third in reserve.”
By the time they reached the middle exit, some divers had already burned through too much air, making further exploration dangerously reckless.
No Guide Line
Without a rope or guideline, the divers had no guaranteed path back to safety. In silted water, even experienced divers can become lost in seconds.
Poor Team Coordination
- Lack of communication under stress
- No clear team roles in an emergency
- Individual skill differences
- Unfamiliarity among divers
All of these worsened the situation as panic and confusion took hold.
Expert Analysis: An Avoidable Tragedy
After the incident, cave diving expert Proer remarked:
“This was an accident waiting to happen. It’s a miracle more people didn’t die.”
The dive was plagued with risks from the start:
- Inadequate training
- Inappropriate diving gear for cave conditions
- No emergency protocols
- Divers with mismatched experience levels
This tragedy reminds us of the extreme caution required when entering hazardous environments, especially in teams where trust and coordination are not well-established.
In some cases, as Proer suggested, it may even be safer to dive solo, where one is solely responsible for decisions and safety protocols.
A Lasting Lesson
The Cape Kinau Cave incident serves as a powerful reminder of the dangers of cave diving:
“Proper training, preparation, and adherence to safety protocols are non-negotiable.”
Key Takeaways:
- Cave diving requires specialized training
- Always plan for redundancy in air supply
- Use guide lines in overhead environments
- Practice team communication and emergency scenarios
- Understand that beautiful environments can become deadly
The loss of Preston Penny was not just a tragic end to an adventure—it was a preventable death caused by a cascade of small, avoidable errors.
As this harrowing story concludes, it stands as a cautionary tale for all divers and adventurers. Beneath the surface lies a world of wonder—but also grave danger. Preparation, experience, and respect for the environment are the only keys to survival.
