New Double Hull Retrofit Design From Stuart Marine
Stuart Marine International, Inc., a Houston-based consulting firm, has developed what it calls a "revolutionary method" to retrofit a double hull to an existing single hull tanker to meet the double hull requirements in the Oil Pollution Act of 1990. The company, which engages in design, engineering, project management, construction supervision, marine services and inspection of oceangoing vessels, calls the new retrofitted double hull DHX, for double hull, external. Stuart Marine International, Inc., says the method complies with USCG NVIC 2-90, which is the Coast Guard's interpretation of the OPA 90.
According to the company, the concept is accepted and can be classed by the regulatory bodies. Several barge and tanker operators are currently interested in this method.
DHX covers the application of an external structure to existing cargo vessels in a simple and economic manner, to provide a double hull/ double bottom configuration as recommended by Marpol 73/78, OPA 90.
Some of the advantages of the externally applied DHX enumerated by the company, include: It will provide the required segregated ballast tank draft; the physical depth and width of the vessel will be increased; cost effective installation; no loss of cargo volume; installation in drydock; it has an energy absorbing "honeycomb" structure which is designed to collapse under impact to prevent the penetration of the inner hull; inspectable by class; no piping or pumping systems required; no void spaces below the waterline, which prevents explosive build up of gases between hulls; and the inert gas system is only required for the upper hull.
The DHX design is currently under a patent application and is protected under patent pending. Stuart Marine International, Inc., hopes to license the concept to shipyards and market it to shipowners and operators. For a free brochure detailing the new DHX concept from Stuart Marine International,