HomeCalculatorsTonnes per Centimetre Immersion (TPC)

Tonnes per Centimetre Immersion (TPC)

TPC = waterplane area × water density ÷ 100. The quick hydrostatic derivative every mate uses to convert a planned cargo mass into a draft change.

StabilityHydrostatics

Inputs

Waterplane area A_wm²From hydrostatic table at current draft.Water

TPC

24.60t / cm

Each centimetre of parallel sinkage adds 24.6 t of displacement.

Formula, assumptions, and limits

ρ in t/m³, A_w in m². Dividing by 100 converts the per-metre rate to per-centimetre. The formula assumes parallel sinkage - valid for small draft changes on a constant waterplane.