Marine Diving Service, Croton

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Croton resident Zdenek Ulman, commonly known as “Z,” is the owner of Marine Diving Service, which he opened four years ago.
Photo credit: Maria Bele

The Marine Diving Service, which is located in Croton, is not your typical business.

Zdenek Ulman, commonly known as “Z,” recalled last week that following his first scuba diving experience he decided to become a scuba diving instructor. “On my way to pursuing my dream to become a scuba diving instructor I stumbled across some of the companies doing some work around the boats and on the docks,” he said.

Ulman said he was hired to do underwater work with commercial scuba divers and his reputation in the business grew. “We did a lot of salvages and repairs and underwater cutting and search and recovery,” he said. “Later on, I decided to open up my own Marine Diving Service company for salvage and recovery because I saw a need for an organized business doing just that.”

Ulman said part of his business is to search for sunken items, barges and other types of vessels. He said his company earlier this year salvaged a sunken large barge in New York City. Many times there are accidents and other emergencies that require boats to be repaired underwater, he said. He noted when there are holes in a boat his company is able “to take care of it before there is a problem.”

If there is a large sunken vessel that needs to be brought to the surface “it becomes a joint effort between other companies with the barges and cranes,” Ulman said. For his part, he will offer his underwater work, such as surveillance and rigging, in an effort to make the repairs and assure the sunken vessel water-tight. Water in the hull of a sunken vessel must be replaced with air, he said.

“The longest salvage we had was 34 hours straight,” Ulman said. “The operation doesn’t stop until the vessel is up because I can’t really stop midway.” The average salvage is 20 hours straight, he said.

Ulman has opened up another division of his company to clean local lakes. “A lot of these beaches are closed this summer because of the invasive aquatic vegetation and also because of the algae,” he said. Ulman’s company recently purchased a machine that removes the invasive plants by their roots, instead of the traditional method of cutting them. One of the company’s recent projects was to improve water quality on the Esopus Creek in the Town of Saugerties in the Kingston area of Ulster County.

“People are very happy,” he said. “They can swim again.” The roughly two-week effort also allowed boats to move through the creek again without being tangled with the invasive plants, he said.

Ulman said algae pose serious health risks and invasive plants can be hazard for swimmers.

Marine Diving Service is located at 3, Ripley Pl #3 in Croton. For more information, call 914-313-6394, send an e-mail to or visit


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