Marine & Boating
Fuel range, anchor scope, tide prediction, hull speed, stability, and passage planning for recreational and commercial mariners.
10 calculators
Hull Speed Calculator
Calculate the theoretical hull speed for a displacement vessel from waterline length.
Marine Fuel Range Calculator
Estimate range, fuel consumption and reserve for a powerboat or sailing vessel under power.
Anchor Scope Calculator
Calculate required anchor rode scope for safe holding at depth.
Sail Area/Displacement Ratio
Calculate SA/D and D/L ratios — key performance indicators for sailing yachts.
Nautical Distance / Speed / Time
Solve any two of distance (nm), speed (knots) and time for passage planning.
Metacentric Height (GM) Estimator
Estimate GM stability from beam and displacement for initial stability assessment.
Tidal Height — Rule of Twelfths
Estimate tidal height at any time between HW and LW using the rule of twelfths.
Fuel Planning — Two-Thirds Rule
Apply the boating safety fuel rule: 1/3 out, 1/3 back, 1/3 reserve.
Marine Rope Breaking Load & Safety Factor
Calculate safe working load from rope breaking strength with marine safety factors.
Dead Reckoning Position
Estimate DR position from a known fix, course, speed and time elapsed.