AUGUST 29, 2014 — The Coast Guard's National Vessel Documentation Center has written a determination letter in relation to the construction by Aker Philadelphia Shipyard of up to eight new MT-50 product tankers with certain foreign-built components and foreign sourced
materials. The vessels are being built for Crowley Maritime Corporation and other
As in prior determinations, the letter says that the vessels' coastwise eligibility will not be compromised by the use of shipbuilding angles, also known as "inverted angles,'' "unequal angles," or "Asian angles,'' purchased from foreign steel manufacturers in standard lengths, widths and shapes and not custom designed for use in the vessels.
The letter notes that the shipbuilder proposes to utilize a ballast water treatment system (BWTS) unit mounted on the main deck above the cargo tanks of each vessel.
"The units are to be prefabricated in a weather-tight enclosure that is attached to the main deck of each Vessel with mounting brackets. However, as described, they will not share a structural boundary with the main deck or other part of the Vessel and, as such, would not contribute to either the structural integrity or flotation envelope of the Vessels.
"Although this type of BWTS has not been considered in prior determinations, upon review by the NAD, we concur with the analogy to the mounting and outfitting of LNG tanks, which have been the subject of prior determinations. As with the LNG tanks, the BWTS units will be structurally separate and independent from the hull and primary hull stresses will not be transmitted to the units. Consequently, we also concur that these units need not be considered in the calculation of the weight of foreign-fabricated components."
Read the determination letter HERE