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scuba diving, initially limited by visibility and equipment constraints. By the mid-1980s, Jerry shifted focus to hunting

Great Lakes shipwrecks, evolving from drop-down standard de? nition cameras to high-de? nition systems with improved lighting and control. With a tight budget and no remotely

Figure 1. Scotiadoc operated vehicles (ROVs), the group innovatively controlled shipwreck as imaged with camera positioning through skillful boat handling and incor-

Theia’s MY125M ultra- wide no distortion lens.

porated a dynamic positioning system using an electronic trolling motor with built-in GPS. This system allows precise station-keeping over wrecks, enhancing imaging capabilities.

Figure 2. Example of strong particulate backscatter due to

LOCATING LOST WRECKS: HISTORICAL RESEARCH close lighting.

AND SONAR

Locating shipwrecks begins long before the boat ever hits the water. The group conducts extensive historical research, poring over old newspapers, life-saving service reports, and archival data. They supplement this with advanced sonar tech- niques, including side-scan sonar built by Jerry’s son Jarrod, and magnetic anomaly detection. By submitting Freedom of

Information Act requests to the National Geospatial-Intelli- gence Agency and applying signal averaging techniques to raw geospatial data, they extract subtle clues about probable wreck locations. This meticulous approach allowed them to pinpoint the Henry B. Smith after nearly a century lost.

The 2013 discovery of the Henry B. Smith was a landmark achievement. Found largely intact about 30 miles off Mar- quette, Michigan, at a depth of 535 feet, the freighter had been lost in the infamous 1913 storm with all hands. Jerry de- scribed the moment they saw the ? ying bridge live on camera as the culmination of years of effort, research, and teamwork.

Their precision in narrowing the search area allowed them to greater depth of the Scotiadoc required improved pressure- locate the wreck within 20 minutes of deploying sonar—an resistant housings, lighting systems, and precision cable con- extraordinary feat compared to previous years of searching. trol—foreshadowing the group's readiness for even deeper expeditions in the future.

PUSHING DEEPER: FINDING THE SCOTIADOC

Later that same year, the group achieved an even more tech- CHALLENGES OF DEEP-WATER EXPLORATION: nically demanding success by con? rming the location of the WIDE-ANGLE, NO-DISTORTION IMAGING

Scotiadoc, a 424-foot freighter that had vanished in 1953 after Whether at 535 or 870 feet, Eliason and his group operate in colliding with another ship in heavy fog near Thunder Bay, near-total darkness. Below 200 feet, natural light disappears

Ontario. The wreck rests upright and largely intact at a stag- entirely, and visibility is further compromised by suspended gering depth of 850, making it the deepest known shipwreck particulates like copepods, which cause “snowy” visual inter- ever found in the Great Lakes. ference when arti? cial lights are too close to the camera (Fig.

Unlike the Smith, which was located through government- 2). To combat this, the group carefully positions lighting 4 to sourced geospatial data, the Scotiadoc was found through 6 feet from the lens, mounted along the same cable (see main sonar searching in a de? ned area based on historic court doc- image).

uments Jerry had obtained. The group had to factor in post- Due to limited visibility and zero ambient light in these collision drift, run sonar in tight grid patterns, and wait for conditions, a distortion free, ultra wide-angle lens with short a rare convergence of good weather, permits, and equipment working distance is essential. To overcome these challenges, readiness to deploy the imaging system. Con? rmation came the group used a Sony SNC-CH240 camera with Theia Tech- when they captured footage of the ship’s name still visible nologies’ MY125M ultra wideangle lens, which offers low along its side (Fig 1). distortion without software correction and a close working “If Henry B. Smith was the entrée; Scotiadoc was the des- distance of just 0.5 meters. On that camera with its HD sen- sert,” Eliason later said, highlighting the technical progression sor and 1920 x 1080 pixel array, the 1.3mm focal length lens the group had made between the two discoveries. The much offers 133 degrees wide in air and from .5m will cover an www.marinetechnologynews.com 37

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