Length at the waterline and length overall

Waterline length, length at the waterline or length, waterline (abbreviated to LWL) is measurement of ships and boats. A ship /ʃɪp/ is a large vessel that floats on water Ships are generally distinguished from Boats based on size A boat is a Watercraft of modest size designed to float or plane on water and provide transport over it The term denotes the length of the vessel at the point where it sits in the water. It excludes the total length of the boat, such as features that are out of the water. Most boats rise outwards at the bow and stern, so a boat maybe quite a bit longer than its waterline length. The bow (pronounced &mdashrhymes with how) is a nautical term that refers to the forward part of the hull of a Ship or Boat, The stern is the rear or aft part of a Ship or Boat, technically defined as the area built up over the Sternpost, extending upwards from the Counter

This measure is essential in determining a lot of properties of a vessel, such as how much water it displaces, where the bow and stern waves are, how much bottom-paint you need, etc.

References

• Hayler, William B. ; Keever, John M. (2003). American Merchant Seaman's Manual. Cornell Maritime Pr. ISBN 0-87033-549-9.  
• Turpin, Edward A. ; McEwen, William A. (1980). Merchant Marine Officers' Handbook, 4th, Centreville, MD: Cornell Maritime Press. ISBN 0-87038-056-X.