What is Parallel Mid-Body Length?
Parallel Mid-Body Length meaning Also known as PBL, PMBL, or Mid-Body Length-This describes the middle side area of a tanker’s or other vessel’s exterior hull which is flat and usually vertical. This is usually the area of the hull that is in contact with the pier when a vessel is docked. This area is measured from aft of the bow where the hull reaches maximum beam and then proceeds aft with little variance until the hull recesses again towards the centerline near the stern. This area is the same on both sides of a vessel and therefore runs in parallel down the middle of the ship. The length of the mid-body is important to know when voyage planning to determine if a vessel will safely be able to moor at a particular facility
source: Inshcape Shipping Services: Glossary of Shipping Terms