OCTOBER 29, 2015 — Classification society ABS has granted Approval in Principle (AIP) to Troy, MI, based Altair ProductDesign for the Cubic Donut Tank System (CDTS) LNG containment concept.
The CDTS concept is adapted from a patent first filed nearly 40 years ago. The principle behind the initial design concept is the construction of a near prismatic shape using 12 interconnected cylinders to create the structural efficiency of a spherical tank and the volumetric efficiency of a membrane tank.
According to Altair ProductDesign, the CDTS retains the advantages of the original concept, including greater relative cargo capacity than either a spherical or membrane containment system, enabling shipbuilders to construct an LNG carrier with a shorter length but comparable draft for a given deadweight.
Altair designers say the CDTS is suitable for operations in heavy sea states at any fill level, and its lower profile compared to spherical tanks for the same cargo volume reduces hydrostatic loading.
"ABS continues to review innovative LNG designs, drawing on 50 years of experience in the safe handling, storage and transport of gas," says ABS Chairman, President and CEO Christopher J. Wiernicki. "As designers apply new solutions to gas carrier challenges, ABS will support this process with approvals that enable LNG shipping to move forward in safety."
ABS says it has completed more than a dozen assessments on new concepts in gas containment in recent years as demand for LNG evolves into small-scale trades, alongside intermediate and large gas carrier concepts.