The desire for exploration is an instinct embedded at the core of human DNA. As we unearth ideas, artifacts, and the unknown, we are humbled to discover what connects us all. There are those that choose to explore terrestrial parts of our planet, those that choose to explore outside our planet entirely and into space, and those who want to journey to the deepest depths of the earth to find what lies beneath the surface of what we know.

Victor Vescovo, an American private equity investor, retired naval officer, sub-orbital spaceflight participant, and undersea explorer, looked to execute the first expedition to reach the five deepest points on the earth: the Puerto Rico Trench in the Atlantic, South Sandwich Trench in the Southern Ocean, Java Trench in the Indian Ocean, Challenger Deep in the Pacific, and Molloy Deep in the Arctic.

Victor Vescovo besides his deep-sea submersible Limiting Factor. (Image credit: Caladan Oceanic)

In the spring of 2018, Triton Submarines reached out to the team at Sea-Bird Scientific, a leading manufacturer and developer of oceanographic instruments located in Bellevue, Washington, to express interest in using their SBE 49 FastCAT CTD (conductivity, temperature, and density) sensor, renowned for its stability and accuracy, for an upcoming project involving a manned submersible. Sea-Bird Scientific has a long history of providing CTDs and water sampling platforms for exploration of the deep ocean floor starting as early as 1992, and therefore was front of mind in being selected as the CTD provider. Sea-Bird Scientific specializes in highly accurate measurements, beyond a thousandth of a degree, which is essential for programs that require extremely accurate measurements.

The SBE 49 FastCAT CTD not only provides vertical positioning through its pressure sensor, it also provides temperature and salinity data from the surface to the operational depth, and back again. This profile data can be used to calculate the speed of sound in water which is important for the proper operation of sonar on the tender ship, DSSV Pressure Drop.

Through this initiative, Vescovo, alongside the Triton Submarines and Sea-Bird Scientific teams, brought together leaders in oceanographic instrumentation from around the globe. These fundamental partnerships led to the creation of Vescovo’s literal and figurative vessel as he attempted to break numerous world records in deep sea exploration through the build of his DSV (Deep-Submergence Vehicle), Limiting Factor, in what became known as the Five Deeps Expedition.

DSSV Pressure Drop at the Mariana Trench. (Image credit: Caladan Oceanic)

The most critical piece of this expedition was the safety of the team involved. The deepest point of the planet’s seabed lies in the Mariana Trench in the Pacific Ocean. The Challenger Deep, the deepest point in the trench clocks in at a depth of approximately 10,928 meters. Anything traversing at this depth is met with an estimated 15,950 pounds per square inch. Therefore, not only did the submarine need to withstand the immense pressure at this depth, but the auxiliary sensors installed on the exterior of the DSV did as well. Not to mention while also garnering quality oceanographic readings to account for accurate reporting of the mission. That’s where the criticality of Sea-Bird Scientific sensor durability and reliability came into play.

Over many months, the Sea-Bird Scientific team worked hand-in-hand with Triton Submarines to ensure the SBE 49 FastCAT CTD was up to the standards necessary to break world records. Uniquely designed for integration on towed vehicles, remotely operated vehicles (ROVs), autonomous underwater vehicles (AUVs), or other autonomous platforms, the SBE 49 incorporates the field-proven Sea-Bird Scientific pump-controlled TC-ducted flow, minimizing salinity spiking where when coupled with its 16 Hz sampling provides very high spatial resolution of oceanographic structures and gradients. Dave Walter, Principal Mechanical Engineer, was the engineering lead on this development for Sea-Bird Scientific and says,

“As a young boy, I remember reading about the Woods Hole Oceanographic Institution (WHOI) team and their Alvin HOV submarine in National Geographic magazine, so having the opportunity to support the Triton Submarines team, and their efforts to fulfill Victor’s dream, allowed me to realize one my childhood dreams: to play a part in underwater exploration.”

A marine technician lowers the DSV equipped with the SBE 49 into the Pacific Ocean to prepare for departure. The SBE 49 can be seen front and center on the submersible. (Image credit: Reeve Jolliffe, Caladan Oceanic)

Through rigorous iterations of testing the SBE 49 at varying depth levels, Dave and the team were able to successfully come away from this project and deliver an easy-to-use, light, and compact instrument with integrated conductivity, temperature, and pressure sensors well-suited for breaking world records.

After all safety checks were accounted for, the Five Deeps Expedition team set out in December of 2018 to attempt the first dive to the Puerto Rico Trench in the Atlantic Ocean, clocking in a depth of 8,376 meters. Throughout 2019, the rest of the remaining four dives were successfully executed, enabling Victor to break numerous world records as intended.

The DSV Limiting Factor and DSSV Pressure Drop during the Indian Ocean dive. (Image credit: Caladan Oceanic)

In a congratulatory letter presented to Sea-Bird Scientific and the project development team led by Principle Mechanical Engineer Dave Walter, Patrick Lahey, President of Triton Submarines, shared, “The Triton 36000/2 represents a quantum leap in the capabilities of a human occupied submersible and everyone at Triton Submarines is immensely proud to have had the privilege and opportunity to create such a remarkable craft, which was only possible by the critical support and creative input of strategic partners and friends like Sea-Bird Scientific.”

As we strive to dive deeper, stay longer, and measure more critical variables necessary for answering climate-related questions, technology must be rigorously tested and redesigned to account for obstacles related to performance and safety. Through strategic partnerships like that of Triton Submarines and Sea-Bird Scientific, the oceanography and broader science community can continue to innovate, expand our understanding, and discover what lies beneath.

Sea-Bird Scientific expresses its thanks to all of those at Triton Submarines for the opportunity to be part of this initiative.

To learn more about Sea-Bird Scientific’s ocean technologies for deep-sea research, visit: www.seabird.com

This feature appeared in Environment, Coastal & Offshore (ECO) Magazine's 2023 Deep Dive III special edition Deep-Sea Exploration, to read more access the magazine here.