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Vessel Displacement Calculator

Calculate vessel displacement from hull dimensions, draft, and block coefficient.

Inputs

ft
ft
ft

Results

Displacement (Long Tons)

33 LT

Displacement (Metric Tons)33.53 MT
Displacement (lbs)73,920 lbs
Underwater Volume1,155 ft³
Underwater Volume32.71 m³
Displacement-Length Ratio770
How to Use This Calculator
  1. Enter the waterline length, beam, and draft of the vessel in feet.
  2. Input the block coefficient (Cb) — typical values: 0.5-0.6 for cargo ships, 0.3-0.4 for fast hulls.
  3. Select water type (saltwater = 64 lb/ft³, freshwater = 62.4 lb/ft³).
  4. Review displacement in long tons and metric tons for loading and stability calculations.
  5. Compare the underwater volume in ft³ and m³ for buoyancy verification.

How the result changes with Waterline Length

Waterline LengthDisplacement (Long Tons)
155146.14 LT
528497.83 LT
977921.17 LT
1,3511,273.8 LT

What each input means

Waterline Length
Length at the waterline, not overall length.
Beam (Width)
Maximum width of the hull at the waterline.
Draft
Depth of hull below the waterline.
Block Coefficient (Cb)
Ratio of underwater volume to enclosing box. Sailboats ~0.35-0.55, cargo ships ~0.8-0.9.
Water Type
Saltwater is denser, resulting in slightly more buoyancy.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Waterline Length = 35, Beam (Width) = 12, Draft = 5, Block Coefficient (Cb) = 0.55 = 5 input(s) provided
  2. Calculate Displacement
    Displacement
    33 = 33
  3. Calculate Displacement
    Displacement
    33.53 = 33.53
  4. Calculate Displacement
    Displacement
    73920 = 73920

Engine last updated . Checked against 3 independently-derived tests — how we verify calculators.

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