Trying to find the displacement for a cruise ship on the Internet is extremely difficult. Generally it’s not given or if it is then it’s confused with gross tonnage which is something entirely different. For example the new MV Viking Mars, on some sites, is erroneously given a displacement equal to its gross tonnage. A simple calculation using its length, beam and drought immediately shows how wrong that is. Why is this metric not given?

  • $\begingroup$ don't you mean draft? $\endgroup$
    – jsotola
    Aug 29, 2023 at 19:06
  • $\begingroup$ @jsotola Its the same word in all contexts, just spelled differently. $\endgroup$
    – Phil Sweet
    Aug 29, 2023 at 23:44
  • $\begingroup$ @PhilSweet ... facepalm $\endgroup$
    – jsotola
    Aug 30, 2023 at 0:45
  • $\begingroup$ Why would anyone 'declare' maximum displacement? It's just a number that comes out of the design for DWT and Gross. $\endgroup$
    – david
    Aug 30, 2023 at 4:38
  • 1
    $\begingroup$ Actually, it's normally spelled draught, I just noticed that the OP spelled it drought. Now that is a different word. $\endgroup$
    – Phil Sweet
    Aug 30, 2023 at 9:24

2 Answers 2


Try equasis.org. Free account.

Enter vessel name (sometimes multiple vessels) or IMO number (best - unique).

Under Classification - Surveys, the info submitted to the appropriate classification society (Llyod's, DNVGL, ABS, etc.) is accessible.

Depending upon regulatory agency, you can get little info or a lot. In this case, bare minimum with Llyod's.

Viking Mars IMO n° 9833187

  • Length overall 228.277m
  • Length between perpendiculars 195.5m
  • Breadth moulded 28.8m
  • Breadth extreme 28.89m
  • Draught max 6.65m
  • Depth moulded 14.73m
  • Gross tonnage 47842t
  • Net tonnage 18858t
  • Deadweight 4526t

The empirical answer is they just don’t. Of course given the dimensions of the vessel it’s trivial to construct the minimum imaginary weightless rectangular box that can contain the vessel and with the draught calculate the maximum possible displacement!

To find the actual displacement under any given condition we would need to know the underwater hull volume at the given draught (with an index of displacements the Plimsoll line would give us the answer) - evidently the commercial marine world considers this data of little interest to overly curious bystanders!


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