Conventional marine propellers remain the standard propulsion instrument for ocean vessels, small to large boats, and underwater vehicles.
Considerations are made to match the engine’s power, shaft speed, the size of the vessel, and the ship’s operating speed with an appropriately designed propeller. This systematic design-process takes time and is one reason that propellers can be very expensive. What happens when one of these propellers dislodges from the vessel and falls to the murky bottom below? Most of the time, the operator does not have the necessary tools to find the missing equipment and must hire an outside diving company to aid in the search. These companies utilize a varying degree of equipment from sonar systems to underwater metal detectors like JW Fishers’ Pulse 8X, which is why so many operators make JWF part of their team!
One company utilizing the Pulse 8X in daily operations is Marine Diving Service, which provides marine diving services to customers on the east coast of the United States. Marine Diving Service has a proven record of successful salvages, from small objects to big vessels, and even a historic tug boat engine. In a recent search, Captain and diver Zdenek Ulman used the Pulse 8X to locate and retrieve an expensive propeller lost at the bottom of the Hudson River. An unnamed vessel lost their 30” diameter propeller, and it was completely buried in the mud with no visible features. Captain Ulman states “I had the general location described to me, but I did not know the exact spot where the propeller was lost.” Ulman utilized his Pulse 8X in an effort to find the missing equipment. He was very pleased with the result, the time savings, and the reduced exposure afforded by JW Fisher’s equipment. “The detector did its job and saved me lot of time in frigid cold waters.” The missing propeller was detected in shoulder-deep mud, “It was easy to use and the strong audio is loud enough to hear through my thick winter hood. Thank you again.”
Pulse 8X Locating Rebar to miss Drilling Anchors
Another company using the Pulse 8X underwater metal detector is Underwater Resources Inc., located in San Leandro, CA. Recently, the company took on a project to locate embedded rebar in a shallow lagoon-basin at a water park. Tom Belcher, President of Underwater Resources, described the complex project. “We conducted a preliminary underwater inspection to locate and mark the embedded rebar throughout the submerged concrete bottom and side-walls. Most of our work was performed at night and during off-hours when the amusement park was closed.” Despite the challenges, the P8X wound up being the right tool for the job. “I can say that the Pulse 8X, with which you had specified using the smaller 5” coil, worked very well for the application. We needed to accurately identify the individual embedded longitudinal and transverse rebar mat alignments. By identifying the rebar locations, we avoided “hitting” any rebar and were able to use pneumatic roto-percussion drills to quickly install and secure our anchors. Thanks for your help with the specification and selection of the 8X.”