Recent Blogs
Schooner Rig Explained: How a Two-Masted Fore-and-Aft Sail Plan Works, Parts and Drive Force
Schooner rig explained — how the fore-and-aft two-mast layout drives offshore sail-training vessels, with sail-area math, worked example, and trade-offs.
Topsail Schooner: Historical Rig and Sail-area Comparison
Explore a square-topsail schooner rig and compare entered sail area with displacement. Also convert weight and compare area and angle inputs; no sailing performance is...
Sloop Yawl Rig and Selected Balance Calculator
See a sloop-yawl rig with jib, gaff main and stern lug sail. Compare selected centers of effort, lateral resistance and waterline length.
Sliding Gunter Rig Mechanism: How It Works, Parts, Formula, and Uses Explained
See a sliding-gunter upper spar rise alongside its mast. Compare mast length, yard length and overlap to calculate the fully raised stack height.
Skiff Yawl Rig Explained: How It Works, Parts, Sail Balance Formula and Diagram
Explore a skiff-yawl rig with headsails, gaff main and small mizzen, and compare main-and-mizzen geometric centers using selected areas and locations.
Jib Topsail Sloop: Idealized Sail-Force Component Calculator | FIRGELLI
Calculate lift, drag and a forward-axis component from entered wind, sail area and assumed coefficients. The diagram does not predict vessel speed, heel or rigging...
Hermaphrodite Brig: Sail-Area Coordinate Calculator | FIRGELLI
Compare an entered sail-area centroid with a lateral-resistance coordinate. This geometric comparison does not predict helm angle, sailing behavior or a suitable rig.
Club Topsail Rig Mechanism Explained: Parts, Diagram, Sail Area Formula and Worked Example
Explore a triangular club topsail above a gaff. Calculate flat cloth area, leech length and separate spar extensions; these dimensions do not establish rig strength...
Barkentine Sail Plan Mechanism: How a Three-Mast Square-and-Fore-Aft Rig Works
Barkentine sailing rig explained — how the square-rigged foremast and fore-and-aft main and mizzen work together for shorthanded ocean trade and sail training.