Mastabstand

Mastabstand is a nautical term referring to the horizontal distance between the bases of two masts on a sailing vessel, most commonly the foremast and mainmast on two- or multi-masted ships. It is a design parameter that influences rig geometry, sail handling, deck layout and overall stability.

The mast spacing is typically measured on the deck plan as the distance between the centerlines of the mast bases, accounting for any rake of the masts. The required spacing depends on factors such as hull beam and length, total sail area, and the type of rig (fore-and-aft, square, or hybrid). A wider spacing can provide greater clearance between masts for sails and rigging, but may increase the lever arm of sail forces and affect stability. A tighter spacing simplifies rigging and deck organization but can limit certain sail configurations and complicate handling.

Designers balance mast spacing with hull form, ballast distribution, and the center of effort of the sails. In two-masted vessels, spacing is chosen to achieve appropriate sail balance and accessibility for crew; in three-masted ships, spacing is distributed along the length to support the intended sail plan. Changes in mast rake or position can alter the effective spacing on deck and the load paths through the vessel structure.

The term is predominantly used in nautical and historical contexts. In modern yacht design, precise mast spacing remains a standard element of rig plans, reflecting performance goals as well as practical handling considerations.