Recent Blogs
Spanish Windlass Mechanism: How It Works, Diagram, Formula, and Rigging Uses Explained
How a Spanish Windlass works — the rope-and-stick tensioning mechanism used by riggers, arborists, and sailors to generate huge force from almost nothing.
Rope Twist Lever (Spanish Windlass) Mechanism: How It Works, Diagram, Formula, and Uses
Rope twist lever explained — how Spanish windlass tensioning works, the force formula, and real worked examples for rigging, arborist, and shelter applications.
Rope End Mechanism Explained: How Whipping, Splices and Heat-Seal Terminations Work
Rope End explained — how to terminate, splice, and seize hemp and synthetic rope ends for rigging, sailing, and arborist work without losing rated load.
Chinese Windlass Mechanism Explained: How It Works, Diagram, Formula, Parts and Uses
Compare two drum diameters on one shaft. Calculate ideal hand force, shaft torque and rise per turn, and see why closer diameters give slower lift...
Block and Tackle Mechanism: How It Works, Parts, Formula, and Mechanical Advantage Explained
How a Block and Tackle multiplies lifting force using rope and pulleys. Mechanical advantage formulas, rigging examples, and real sailing and crane applications.
White's Pulleys Mechanism Explained: How a Single-Rope Stepped-Sheave Tackle Works
Explore pulley effort and rope travel using an entered mechanical advantage and efficiency. The simplified support-force sum is not an anchorage rating.
Two Fixed and One Movable Pulley: Three-part Tackle Calculator
Explore the shown 3:1 tackle and compare haul force using an assumed per-sheave tension ratio. Results do not rate a lifting system.
Spanish Barton (form 2) Mechanism Explained: 5:1 Compound Pulley Parts, Formula & Rigging Uses
Spanish Barton form 2 rigging explained — how stagehands and riggers achieve 5:1 mechanical advantage with two single blocks to lift heavy loads safely.
Simple Lifting Pulley Mechanism: How It Works, Diagram, Parts, Formula and Uses Explained
Explore a fixed pulley with a continuous rope animation. Calculate effort from load and selected efficiency, plus the sheave-to-rope diameter ratio.
Movable-Pulley Cord System (d): Fixed-Redirect 2:1 Ledger
How a cord-and-movable-pulley system halves lifting force. Real worked example, mechanical advantage formula, and rigging examples for shop and field use.
Movable-Pulley Cord System (c): Standing-End and Haul-Line Ledger
How a cord-and-movable-pulley system halves lifting force in rigging, theatre, and workshop hoists. Mechanical advantage formulas, worked example, and diagrams.
Movable-Pulley Cord System (b): 2:1 Lift with Right-Angle Haul
Movable pulley systems with cord cut lifting force in half or better. See how riggers, theatres, and shipyards use them to hoist heavy loads with...
Movable-Pulley Cord System (a): Fixed 2:1 Reeving Ledger
Movable pulley systems with cord cut lifting force in half or more. Learn the mechanical advantage formula, real rigging examples, and design tradeoffs.
Swinging Derrick Crane: Load-moment Comparison
Compare load times horizontal radius with an entered moment reference. Explore ideal moment arithmetic and illustrated boom geometry without inferring crane capacity.
Swing Derrick: Radius and Ideal Swing Calculator
Explore boom projection and ideal swing motion. Compare working radius, an entered moment/radius quotient, angular speed and hook plan speed.
Lever Grip-Tongs: Hiscox Item 1461 Motion Viewer
See how shackle pull closes lever grip-tongs through their connecting links and upper arms. Compare three schematic positions without a lifting-capacity claim.
Cable Hoist and Conveyer Mechanism Explained: How It Works, Parts, Reeving Diagram and Uses
Explore a travelling cableway trolley and ideal hoisting tackle. Compare per-fall rope tension and hook-to-rope speed ratio from total suspended mass and fall count.
Stevedore Knot Mechanism Explained: How It Works, Parts, Uses, and Sheave Jam Calculator
Learn how the Stevedore Knot works as a stopper knot for sailing rigs and load handling, with sizing rules, worked examples, and comparison to figure-8...
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.
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.
Figure-Eight Knot: Forms and Assumed Strength Comparison | FIRGELLI
Compare assumed rope-strength retention and load arithmetic. Learn the distinction between figure-eight forms and why the outputs do not certify a rope system.
Bowline Knot Mechanism Explained: Parts, Diagram, Strength Formula, and Real-World Uses
Trace a bowline’s continuous rope route, nipping loop and collar. Compare assumed retained breaking strength and a chosen tail allowance, separately from load ratings.
Hydraulic Pulling Jack: Full-Bore and Annular Force Calculator | FIRGELLI
Compare ideal full-bore and rod-side annular force from bore, rod diameter and applied pressure. Opposing pressure, attachments and safe pulling capacity are not calculated.
Block and Tackle: Supporting-Parts and Ideal Work Ledger
How a Pulley works, with the formula, real industrial examples from cranes to elevators, and engineering tradeoffs vs gears, levers and hydraulics.