Model Ship Rigging Calculator

Rigging a scale model ship means shrinking real ropes and mast heights down to a size where thread and wire can stand in convincingly, and this calculator handles both conversions. Mainmast height in the model is simply the real mast height (converted from feet to inches) divided by your scale denominator. Thread diameter assumes real ship's rope ran about 1.5 inches in diameter — a reasonable average for many rigging lines — scales that down by the same denominator, and converts the result to millimeters, since thread and wire are typically sold in metric diameters. Total rigging length is estimated by treating shrouds (the lines bracing the mast side-to-side) as roughly 1.2 times the model mast height each, since they run at a diagonal from deck to masthead rather than straight up, and stays (the fore-and-aft bracing lines) as roughly 1.5 times mast height, since they typically run at an even shallower angle over a longer span.

Ratline count — the horizontal rope rungs sailors climbed — is derived by scaling down your real-world ratline spacing and dividing that into 70% of the model mast height, reflecting that ratlines typically only run up the lower shrouds rather than the full mast to the truck. A rig-complexity score from 1–10 combines shroud and stay counts with ratline count as a rough gauge of how much rigging work lies ahead. These are practical modeler's approximations, not scaled tension or rope-physics calculations, so expect to adjust thread diameter and lengths against reference photos of your specific vessel.