Hydrostatically balanced loading (HBL) was approved in July 1993 by the
International Maritime Organization, under amendment 13G to Marpol, as
a method of reducing the risk of oil spills from single-hull tankers.
The US Coast Guard is now considering how to apply the amendment to OPA
'90.
Under the amendment, pre-Marpol tankers - vessels built before 1980, and
accounting for about 255 VLCC/ULCCs - can trade up to 30 years of age
if they adopt HBL.
