Mean / True Mean Draft

Mean draft and UNCTAD 'mean of means' draft at the LCF - the reference every draft-survey starts with.

StabilityDraft survey

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This calculator requires JavaScript to compute its result. The formula, symbols, and regulatory sources are shown in the Formula section below.

Formula, assumptions, and limits

T_{MoM} = \tfrac{T_F + T_A + 6 T_M}{8}, \quad T_{LCF} = T_{mean} + \text{Trim} \cdot \left(\tfrac{LCF}{L_{pp}} - \tfrac{1}{2}\right)

Symbol	Meaning	Unit
$T_F, T_A, T_M$	Forward, aft, midships draft	m
$LCF$	Long. centre of flotation from AP	m
$L_{pp}$	Length between perpendiculars	m
$Trim$	Aft − fwd draft (stern positive)	m
$T_{LCF}$	True mean draft at LCF	m

Source: UNCTAD - *Draft survey guidelines* (1991); Derrett & Barrass

Mean draft, mean-of-means and UNCTAD true mean draft at LCF.