Recent Blogs
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...
Serpollet's Steam Tricycle Mechanism: How the 1887 Flash Boiler Steam Vehicle Works
Serpollet's Steam Tricycle used a flash boiler to power a 3-wheeled road vehicle in 1887. Learn the mechanism, formulas, and worked example for heritage builds.
Self-registering Tide Gauge: How It Works, Stilling Well Diagram, Parts, Uses & Orifice Calculator
How a self-registering tide gauge works — float, stilling well, drum recorder, and clockwork. Used in harbour engineering and coastal survey work.
Screw Propeller Mechanism: How It Works, Parts, Diagram, Formula and Marine Uses Explained
How a Screw Propeller works — blade geometry, pitch, slip, thrust calculation, and worked examples from marine, aviation, and submersible propulsion.
Sampler Sounding Weight Mechanism Explained: Parts, Diagram, Formula and Hydrographic Survey Uses
How a Sampler Sounding Weight measures water depth and grabs a seabed sample in one drop. Used by hydrographic survey crews, dredging contractors, and marine...
Round Turn and Half Hitch: Mechanism, Capstan Formula, Parts, and Mooring Uses Explained
Round turn and two half hitches knot explained — how the wraps absorb load, breaking-strength figures, and real mooring and rigging applications.
Rope Knots and Hitches Explained: How They Work, Key Parts, Knot Efficiency and Working Load Limits
Rope knots and hitches explained — how friction, bend radius, and load path determine holding strength in rigging, sailing, arboriculture, and rescue work.
Road Roller Mechanism Explained: How Vibratory Compaction Works, Parts, Formula and Uses
How a Road Roller compacts asphalt and soil — drum geometry, vibration physics, lift thickness math, and pass-count rules used by paving crews worldwide.