Feature: Rebuilding Single Hull Tankers to Double Hull Tankers
Since then Maritrans has successfully rebuilt three similar size barges and is currently working on a fifth that includes a 60-ft. lengthening. Maritrans patented barge process was described in detail in our earlier article. As is shown in Figure 2, an inner bottom and double side is built upon the existing single hull structure. (Red is new and blue is existing.) New lower bulkheads are also constructed. The existing deck and upper bulkheads are returned in such a fashion as to create a raised trunk to retain the original cargo volume. Maritrans learned a great deal from its barge rebuild program in terms of pre-measurement, modularization, assembly process, and efficient detailing. Now the company is ready to apply these lessons to an even greater challenge: rebuilding tankers.
Maritrans Secures Patent for Converting Single-Hull Tank Ships
Maritrans Inc. has obtained a patent on its proprietary process for rebuilding single-hull tank ships and converting them into double-hull vessels. With the most recent patent, Maritrans has now patented the double-hull conversion process for both barges and tank ships. The U.S. Oil Pollution Act of 1990, as well as the International Convention for the Prevention of Pollution from Ships (MARPOL), each require the retirement of single-hull tank vessels. In January of 2001, Maritrans announced that it had received the first of three patents for internal double-hull conversions of single-hull barges. These Maritrans patents involved pre-fabrication of large tank structures that are inserted into the existing hull, with a trunk deck extending above the pre-existing deck.
