The first-ever human descents to the deepest points of both the Yap and Palau Trenches are the latest achievements of undersea adventurer Victor Vescovo, in his unique two-person any-depth submersible Limiting Factor.
The founder of Caladan Oceanic recorded a maximum depth of 8,929m in the Yap Trench, accompanied on the dive by Grand Master Navigator Sesario Sewralur of Micronesia, and 8,027m in the Palau Trench (plus or minus 9m in each case) in the company of former Palau president Thomas Rememngesau.
In the Pacific the title “Navigator” is accorded to seafarers able to cross the ocean using only natural guides such as ocean currents, winds and stars. Sewralur has been recognised for his exceptional navigational skills – though these were not needed on his record-breaking vertical descent.
Before the dives both trenches were extensively mapped from mother ship Pressure Drop using the expedition’s multibeam sonar system to identify the deepest points and areas of interest to be explored and mapped in detail. Samples were collected at various depths on the dives to be shared, along with collected data, with local scientific and other communities.
The deep-sea habitats were observed to be similar to those of the Mariana Trench, the deepest in the world, but with slightly more wildlife as might be expected at shallower depths. High vertical walls were encountered in both trenches, where the Caroline tectonic plate is slowly being pushed beneath the Philippine plate. In the Yap Trench, Vescovo and Sewralur ascended one vertical wall that towered more than 1km high.
“I believe both of these areas have been overshadowed by the larger and even deeper Mariana Trench to the north-east, but these isolated trenches have their own geological history and characteristics that are worthy of their own deep ocean exploration,” pointed out Vescovo.
Unfortunately some unidentified human contamination was also recorded in a fleeting moment at the bottom of the Palau Trench, thought to have been plastic sheeting.
While Vescovo dives, Pressure Drop and its team continue to map the seabed in support of the GEBCO 2030 initiative to record the entire seafloor by the year 2030.
An area covering more than 100,000sq km has already been mapped throughout the Philippine Sea and other areas of the Western Pacific during the 2022 Ring of Fire Pt 2 programme. The latest expedition was again led by Rob McCallum of EYOS Expeditions, and technical partner Triton Submarines, which built Limiting Factor.
Alvin boosts depth rating
Perhaps in danger of being overlooked as Vescovo's Limiting Factor breaks one record after another, the world’s oldest deep-sea submersible Alvin has had a major upgrade to enable it to access “roughly 99%” of the world’s seabed – and has just carried out the deepest dive in its 58-year history in the Puerto Rico Trench.
The USA's Woods Hole Oceanographic Institution, which operates the three-person Alvin, was aiming to achieve US Navy certification to resume operations after an 18-month overhaul and upgrade that has extended its maximum dive rating from what was by modern standards a modest 4,500m to the 6,453m it achieved off Puerto Rico.
Originally constructed in 1964, Alvin has now completed 5,086 successful dives, more than all other submersible programmes worldwide combined, carrying some 3,000 pilots and observers into the ocean depths.