MY SIMULATOR

English Canal
Boat Simulator

Navigate the waterways of England.

Section Lock chamberSpeed 0 mphCritical 0 mphDrawdown 0 cmBlockage 0Gates closedFPS 0

0.0 mph

Water level (canal depth)

Narrowboat in the Cut

A 21 m narrowboat pushes water aside; in a narrow canal the water can only squeeze past, so it speeds up, the surface drops and the boat squats. Drag to orbit, wheel or pinch to zoom. Press Explore the canal to cast off, or set the throttle yourself.

Power source

Boat and water

Where on the canal

Channel cross-section (2D)

Live readouts

Resistance and propulsion

Drawdown in each section

Experiments

Each button recomputes the physics for the current boat load.

Independent numerical checks

The science

Blockage and return flow. The boat blocks area A_s = B T C_m of a channel of cross-section A_c = W h. Seen from the boat, water arrives at speed v and must pass the hull through the free area A = W(h − z) − A_s, where z is the drawdown of the surface. Mass conservation gives V_g = v W h / A; Bernoulli gives z = (V_g² − v²)/(2g). Solving these two equations (the 1-D Schijf model) gives the drawdown and the squat.

Critical speed. As v grows the two equations stop having a solution: the flow beside the hull becomes critical, V_g² = g A/W. That is the speed limit of the channel; beyond it a displacement boat cannot go without huge power. Narrow places (bridge holes, tunnels, locks) lower it a lot, which is why boaters slow down there. Many UK canals post a 4 mph limit because wash also erodes banks.

Resistance. Friction acts at the faster speed V_g past the hull: R = ½ ρ C_f (1+k) S V_g² with ITTC-1957 C_f = 0.075/(log₁₀Re − 2)². Effective power is R v. The engine thrust is the smaller of the bollard limit (2 ρ A_d (ηP)²)^1/3 and ηP/v_a; a horse pulls with F = F₀(1 − v/v_max) cosα, which peaks at F₀v_max/4 (about 650 W, a bit under one horsepower). The boat then accelerates with (m(1+0.35)) dv/dt = T − R (35 % added mass).

Honest simplifications. The channel is a rectangle of the section width; the real canal is trapezoidal with sloping banks. The solution is steady and one-dimensional (no waves, no trim, no bank suction, no rudder forces). Form factor, added mass, propeller and horse constants are typical, not measured. The drawdown in the 3-D view is shown 3 times larger than real so that you can see it. This is an educational model, not a navigation guide: real locks, tunnels and tow ropes are dangerous.

Made with Blender · Three.js. Educational only.

English CanalBoat Simulator

English Canal
Boat Simulator