Kroehl listed himself as a "submarine engineer" on Broad Street in
Lower Manhattan during the 1850s. At this time, the term "submarine" referred to anything underwater, and not exclusively to diving vessels. During this time, he was involved in several engineering and technical projects.
Photography An 1851 article in
Scientific American magazine describes the Fair of the American Institute. One exhibit was of colored photographs by Messrs. Kroehl & Vetter, of No. 499 Broad Street. This does not necessarily mean this was Julius Kroehl. However, when Kroehl was ordered to support Union forces during the Vicksburg Campaign of 1863, he was directed to bring with him photographic equipment after spending one month being trained on their use by members of the U.S. Coast Survey in Washington, DC. His personal effects enumerated at the time of his death included photographic supplies. His proficiency in photographic uses in 1851 was possible. No works are known to have survived.
New York Crystal Palace From 1852 to 1853, Kroehl was employed as an assistant engineer during the construction of the
New York Crystal Palace. Several assistant engineers were employed to oversee the construction of certain parts of this exhibition hall. He was responsible for the construction of the dome, the building's central feature. For three years after, he was noted as the "engineer of the Crystal Palace."
Flange forming machine Kroehl applied for a patent around March 1854 for a
flange forming machine. It is described in
Scientific American as an improvement in machinery for bending flanges on wrought iron beams. There is a pair of horizontal, and a pair of vertical rollers; the former pair has one roller with a face of the full depth of the beam, and the other has its face the depth of the beam minus the thickness of the flanges. The vertical rollers are both alike, and are of a width a little greater than the extreme width of the flanges. They are arranged opposite the space between the horizontal ones, and work in close contact with the sides of the roller. In order to give the flanges and their beams, a taper or an elliptic, or other curved form, the vertical rollers have flanges, whose faces bear on the edges of the flanges of the beam, and cause the said rollers to receive such a movement in the direction of their axes, and apply such a force I that direction as bends the flanges of the beam to the desired form. Kroehl secured the patent as #12,133 on January 2, 1855.
Mount Morris Fire Watchtower The City of New York, in order to improve safety during its growth, laid out a series of fire watch towers.
James Bogardus, an innovator of cast iron houses, introduced the first of these towers. One was needed in the
Harlem district, which would be situated on an outcropping of rock. On January 14, 1856, the Commissioner of Repairs and Supplies received two bids. Bogardus submitted his usual design at a bid of $5,750, but Kroehl and his partner Peter V. Husted (H&K) won the contract with a lower bid of $2,300; H&K pointed out that the tower need not be as tall, thus saving material and labor. This tower still stands in what is now
Marcus Garvey Memorial Park. Comparing the structure and techniques of this tower with those designed and constructed by Bogardus show many similarities, especially in the method of bolting joints together. In April 1857, Bogardus sued the Mayor, Aldermen and Commonalty of the City of New York, claiming a patent infringement (#7,337). He cited that he was entitled to a royalty payment of $289, plus actual damages of $20,000. The jury agreed that he was entitled to the royalty payment, but not to the damages. Bogardus appealed the ruling to the
U.S. Supreme Court, but Supreme Court Chief Justice
Roger B. Taney upheld the ruling on appeal.
Vanderbilt Rock On 21 May 1853,
Cornelius Vanderbilt's yacht, the
North Star, ran aground on
Corlear's Hook and had to go back to dry dock for repairs, though no material damage was sustained. The area was then called "Vanderbilt Rock" with the expectation that City and State officials would arrange its removal as a hazard to navigation. For over a year, no action was taken. Later, H&K received a contract and they promptly removed the obstruction.
Diamond Reef The maritime hazard of Diamond Reef lies at the entrance to the
East River between
Governor's Island and Lower Manhattan.
Benjamin Maillefert was favored to win the contract based on his experience with underwater demolition and salvage. He attempted in 1851 to reduce this underwater obstacle by blasting. This effort was accomplished by lowering a canister of powder onto the rock at flood tide, then backing away a safe distance, detonating it with a galvanic battery. However, this was not yet deemed sufficient, and another bid was undertaken a few years later. Kroehl & Husted was one among five bidders. The Common Council awarded the contract to H&K, but Mayor
Fernando Wood vetoed the contract on August 7, 1855, citing that the Council did not have the authority to award contracts, since such authority resides with the Street Commissioner. After appeals and new bidding, H&K was awarded the contract without further dispute, and proceeded to remove the underwater hazard. Blasting operations continued every year, except during the winter months, until 1860.
Merlin Rock Peter Cooper, as president of the
New York and Newfoundland Telegraph Company, hired H&K to blast Merlin Rock, which lies at the western end of the narrows in St. John's Harbor, in June 1855. They were successful in accomplishing the work by August of that year, to the contracted clearance of 27 feet.
Outfitting the Paraguay Expedition of 1858 During the demolition of Diamond Reef, H&K provided underwater explosives to the U.S. Navy for clearing obstructions in the
Platte,
Parana and
Paraguay Rivers, should the ships encounter any. The items were provided to the steamer
USS Memphis.
Norfolk Navy Yard On 1 July 1859, F.W. Parmenter, a machinist from
Troy, New York, contracted with the Navy Department to construct, erect and complete an iron roof for the victualling house at
Norfolk Naval Shipyard in the amount of $18,000. Julius H. Kroehl and Sidney D. Roberts served as sureties for the contract. However, monies appropriated for the project were spent elsewhere, so worked dragged through 1861, with work being performed with the assurance that the U.S. Congress will appropriate supplemental funds. But the seizure of Norfolk by Confederate forces in April 1861 forestalled final completion of the project, with an amount owed to Parmenter. In 1874 and 1876, House Committee reports for private relief recommended that the outstanding amounts be paid. ==American Civil War==