Recent Blogs
Three-quarter Lug Rig: Historical Two-mast Arrangement
Explore Hiscox’s two-mast rig with two lug sails and a bowsprit-stayed jib. Adjust an illustrative mast layout; sail forces and performance are not calculated.
Cutter Sailing Rig: Sail-area and Displacement Ratios
Explore a traditional cutter rig, calculate conventional sail-area/displacement and displacement/length ratios, and compare a chosen headsail-area allocation.
Ten-wheel Freight Locomotive: Historical Tractive-force Estimate
Explore the 4-6-0 wheel arrangement and a historical starting-force estimate from cylinder size, pressure and driver diameter. Actual train capacity is not predicted.
Swinging Oar-lock: Ideal Pin-force Calculator
Explore ideal oarlock force from handle force and inboard/outboard lengths. Compare a perpendicular-force scenario without inferring hardware capacity.
Swinging Ball-bearing Pedal: Basic Bearing-life Calculator
Explore a historical ball-bearing pedal and a generic L10 calculation. Compare basic rating life from dynamic rating, equivalent bearing load and relative speed.
Submarine Lamp: Hiscox Underwater Lamp, Diagram & Pressure Calculator
Explore the Hiscox underwater lamp with separate air and exhaust hoses. Calculate water pressure and force on a circular lens without assuming a depth rating.
Streetcar Sand Box: Animation and Adhesion Comparison | FIRGELLI
Follow a rail sander’s hopper, valve and delivery pipe. Compare two ideal stopping distances from entered speed and adhesion coefficients.
Street Railway Sweeping Car: Paired-brush Motion Calculator
Explore paired diagonal rail brushes. Calculate nominal tip speed, lateral and along-track components, and rotation frequency from entered diameter, RPM and angle.
Street Cleaning Machine: Sweeper Route Coverage Calculator
Compare effective sweep width, working speed and productive shift time. Estimate hourly area, shift coverage and distance along a single swept band.
Stone Dry Dock: Animation and Pump-Rate Calculator | FIRGELLI
See a vessel settle onto bearing blocks as a fixed basin drains. Estimate rectangular water volume, target drainage rate and the effect of leakage.
Square or Reef Knot Mechanism: How It Works, Diagram, Parts, Uses and Strength Formula Explained
How the Square or Reef Knot works, why sailors use it for reefing sails, where it fails, and how to tie it correctly for binding...
Square or Lug Sail Mechanism: How It Works, Parts, Diagram and Sailing Uses Explained
How a square or lug sail works, with rigging geometry, drive force formulas, and a worked example for traditional boatbuilders and sail trainers.
Spring Wheel Mechanism: How It Works, Diagram, Parts, Uses & Calculator Explained
Spring Wheel mechanism explained — how flexible spokes absorb shock, where militaries and rovers use them, with sizing math, tradeoffs, and a worked example.
Split Lug or Square Sail: Mechanism, Sling Point Diagram, and Rig Parts Explained
Split Lug and Square Sail rigs explained — geometry, sail forces, and trim numbers for small craft, training boats, and traditional workboat restorations.
Sounding-weight Release Mechanism: How It Works, Parts, Diagram, and Deep-Sea Sounding Uses
Sounding-weight release mechanisms drop a lead from a sounding line on bottom contact so hydrographic crews recover the line clean. Specs, formula, worked example.
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.
Sloop Rig: Mainsail, Jib and Forestay Calculator
Explore a sloop mainsail and jib with a moving boom. Calculate selected forestay tension percentages and midpoint sag distance.
Slip Knot Mechanism Explained: How It Works, Parts, Uses, and Quick-Release Diagram
Learn how a Slip Knot works, why riggers and arborists trust it for quick-release loads, and how to size it correctly with a worked example.
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.
Skip Jack Mechanism Explained: How the Ratchet and Pawl Lifting Jack Works, Parts and Uses
Skip Jack mechanism explained — how the ratchet-and-pawl lifting jack works, where road crews use it, formulas, worked example, and failure modes.
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.
Single-Cylinder Locomotive: Centre-Crank Animation and Leverage Calculator
Watch a single-cylinder locomotive centre crank, piston and crosshead. Compare ideal crank leverage at two selected angles and distance from dead centre.
Silver's Marine Governor Mechanism Explained: Parts, Diagram, and How It Controls Marine Steam Engines
Silver's Marine Governor controls steam engine speed against varying propeller load at sea. Learn how this 1860s flyball governor works, with formulas and a worked...
Sheet Bend and Toggle Mechanism: How It Works, Diagram, Parts, Uses and Safe Load Formula
Sheet Bend and Toggle explained — how this quick-release rope joint works, why riggers and sailors use it, with worked load math and failure diagnostics.
Sheet Bend Knot Mechanism Explained: How It Works, Diagram, Parts, Uses & Load Formula
Sheet Bend knot explained — how it joins two ropes of unequal diameter, with strength figures, failure modes, and worked examples for marine and rescue...