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In-water cleaning, also known as in-water surface cleaning, is a collection of methods for removing unwanted material in-situ from the underwater surface of a structure.. This often refers to removing marine fouling growth from ship hulls, but also has applications on civil engineering structures, pipeline intakes and similar components which are impossible or inconvenient to remove from the ...
An Old Whaler Hove Down For Repairs, Near New Bedford, a wood engraving drawn by F. S. Cozzens and published in Harper's Weekly, December 1882. Careening (also known as "heaving down") is a method of gaining access to the hull of a sailing vessel without the use of a dry dock.
In brief, corrosion is a chemical reaction occurring by an electrochemical mechanism (a redox reaction). [1] During corrosion of iron or steel there are two reactions, oxidation (equation 1), where electrons leave the metal (and the metal dissolves, i.e. actual loss of metal results) and reduction, where the electrons are used to convert oxygen and water to hydroxide ions (equation 2): [2]
The negative cable from the power supply is simply attached to the hull to complete the circuit. Ship ICCP anodes are flush-mounted, minimizing the effects of drag on the ship, and located a minimum 5 ft below the light load line [26] in an area to avoid mechanical damage. The current density required for protection is a function of velocity ...
For some modern types of dinghies in sailing sports hand bailers can be obsolete when they are equipped with self bailers, sometimes also called automatic bailers. Self-bailing boats are shaped so that they will drain completely if filled with water; powered by the venturi effect and the motion of the boat, they are distinct from the powered bilge pumps used on non-self-bailing boats.
A hull maintenance technician using a cutting torch aboard the USS Nimitz. Hull maintenance technician (abbreviated as HT) is a United States Navy occupational rating.. Hull maintenance technicians plan, supervise, and perform tasks necessary for fabrication, installation and repair of all types of shipboard structures, plumbing, sheet metal fabrication, carpentry and piping systems; organize ...
Water that does not drain off the side of the deck or through a hole in the hull, which it would typically do via a scupper, instead drains down into the ship into the bilge. This water may be from rough seas, rain, leaks in the hull or stuffing box, or other interior spillage. The collected water must be pumped out to prevent the bilge from ...
The strong acidification of the medium caused by pyrite oxidation releases bicarbonate ions (HCO − 3) or carbon dioxide (CO 2) along with calcium (Ca 2+) and sulfate ions (SO 2− 4). Full pyrite oxidation can be schematized as: 2 FeS 2 + 7.5 O 2 + 4 H 2 O → Fe 2 O 3 + 4 H 2 SO 4. The sulfuric acid released by pyrite oxidation then reacts ...