net tonnage
Webster's Dictionary (GCIDE)
Net \Net\, a. [F. See Neat clean.]
1.Without spot; pure; shining. [Obs.] [1913 Webster]
Her breast all naked as net ivory.— Spenser.[1913 Webster]
2.Free from extraneous substances; pure; unadulterated; neat; as, net wine, etc. [R.] [1913 Webster]
3.Not including superfluous, incidental, or foreign matter, as boxes, coverings, wraps, etc.; free from charges, deductions, etc; as, net profit; net income; net weight, etc. [Less properly written nett.] [1913 Webster]
Net tonnage (Naut.), the tonnage of a vessel after a deduction from the gross tonnage has been made, to allow space for crew, machinery, etc. [1913 Webster]