Wednesday, 11 May 2016

RECTIFYING THE LIST.

Frank Edward Thomas. 

Shipping clerk to agents 

Passenger, Adelaide to Sydney. 

I saw nothing while I was on board to correspond with the reported statement of Mr. Sawyer at Durban. The only thing I noticed was that on leaving Melbourne for Sydney she had a slight list to starboard, and on the next day on looking over the side I noticed she was discharging rusty-looking water. The chief engineer came along, and I asked him the cause. and he said they were pumping out a tank to rectify the list. The list, however, continued.



It makes sense that ballast needed adjustment after discharging cargo at Melbourne. One does however wonder about rusty water from ballast tanks one year in service. Perhaps it was the norm? 

This wikipedia extract puts the issue into perspective:

One of the most common problems among vessel construction and maintenance is the corrosion that takes place in the double hull space ballast tanks have in merchant vessels.[6] Bio-degradation takes place in ballast tank coatings in marine environments. To avoid biodegradation, paint has been a new idea to stop the corrosion of ballast tank. Ballast tanks can carry more than ballast water, most of the time ballast tanks are filled with other bacteria or organisms. Some of these bacteria can that can be picked up from other parts of the world can cause the ballast tank to get damaged. Bacteria from different regions plus the natural bacteria can cause ballast tanks to break down. The natural bacteria community has an interaction of the natural bio-films with the coating, an aspect which is not covered in standard procedures. Researchers have shown that biological activity indeed significantly affects the coating properties. Micro-cracks and small holes have been found in ballast tanks. Acidic bacteria created holes with 0.2–0.9 μm in length and 4–9 μm in width. The natural community caused cracks of 2–8 μm in depth and 1 μm in length. The EIS technique was used to examine the degradation. The bacterial affected coatings decreased in corrosion resistance. The natural community, has a clear loss in coating resistance over time. Also, coating corrosion resistance declines after 40 days of exposure to the natural community, resulting in blisters in the ballast tank. Bacteria might be linked to certain bio-film patterns affecting various types of coating attacks.



inescapable rust.

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