Saturday, January 16, 2016

FTV Deck Maintenance

Cadets needle gunning,getting rid of all of the rust spots, and repainting the Helo deck
Of the three main tasks cadets perform on board the ship maintenance, is at the top of the list. Maintenance is on a ship is similar to maintenance of a car, it is just a larger scale and there is more exterior work along with the engine work. We finally had some  nice weather and the sea was calm so we were able to do some outside deck maintenance and outside engineering maintenance. 

With deck maintenance we use many different tools for the many jobs. The main job that cadets do on the ship is needle gunning, which is chipping the old paint and rust off of the ship. After they needle gun the cadets prime and paint what they chip off. This is important because it keeps the exterior of the ship in good condition so it does not rust. Also it makes the ship look a little nicer. Other deck maintenance jobs are maintaining the cranes, securing any goods and material that is adrift and general up keep of the ship.

During maintenance depending on what jobs a cadet is doing they all need the proper PPE (personal protection equipment). For example, with  the job of needle gunning cadets need proper hearing protection, which could be ear muffs or ear plugs. In addition they need safety glasses or goggles and proper hand protection like gloves. Some needle gunning jobs require a breathing mask or respirator, to prevent  inhalation of  a piece of metal or a piece of paint chippings which can travel to the lungs and cause great damage.

Corrosion takes place whenever unprotected steel is exposed to the air. In the salty atmosphere of a ship at sea this corrosion takes place with considerable speed. What exactly is rust? Rust is the red-brown oxide of iron formed by the action of moisture and oxygen on the metal.

Rust-treatment products Polymer-based ‘paints’ are available that contain ingredients that react chemically with rust to form a tough polymer layer that bonds well to the metal surface. These have the following features: only the loose flakes of rust need be removed prior to treatment, they are generally more fluid than paint and so are more easily applied, some kinds can be applied under water (for small areas) and very long lifetimes are claimed for these paints.

Small blocks of zinc are attached to ships to prevent corrosion of the hull
Small blocks of zinc are attached to the steel hull of this ship. 

Corrosion can also be controlled by connecting the object to be protected to another object made of a metal that is corroded even more easily. When an iron nail is wrapped with a strip of zinc and exposed to water, the zinc (being a more active metal than iron) is oxidized while the iron remains intact. This technique, called cathodic protection, is commonly used to prevent the hulls of steel ships from rusting. Blocks of zinc are attached to the underside of the hull  The zinc blocks corrode more slowly keeping the hull intact. The zinc blocks must be periodically replaced to maintain the protection of the iron.

Learn more about the chemistry of rust
Can You Copperplate?
Can you swab the deck? Try it out!
Rusty Reactions
Can you prevent rusting?

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