Free · on your phone · nothing to install
Harbour manoeuvring simulator
Berth alongside, at the fuel dock, or bow-to and stern-to between boats, with or without wind, in a sailing yacht or a twin-engine motor boat. With a wheel and a throttle, just like on board.
Approximate simulation: the real boat behaves much the same, but the sea always surprises.
In short: a free harbour manoeuvring simulator built by Ricard Prehn, yacht captain and sailing instructor for more than 27 years, for the students of Escuela Náutica Altair (Port Garraf) and for anyone who wants to understand why a boat has no brakes, which way the propeller pulls going astern and how the wind moves you when berthing.
The five manoeuvres
Berthing alongside needs no sign-up. The rest are free with your email, so we can tell you when a new manoeuvre comes out.
Berthing alongside
Port side to the quay, in a gap between two boats. With wind pushing you off, on, or from ahead.
Fuel dock
Starboard side to with a breakwater ahead: here the burst astern swings your stern out instead of in.
Bow-to mooring
Bow-first between boats moored end-on, in a realistic marina fairway.
Bow-to, two free berths
Two free berths side by side and the wind pushing you into the empty one: stay in the windward berth.
Stern-to mooring
Mediterranean mooring, only with no wind: go past, angle the bow against prop walk and reverse in with very little helm.
Stern-to mooring, step by step
When to do it and when not to (in a wind, bow-first), and the manoeuvre as we teach it: go 30 m past, angle the boat and reverse in with little helm.
Read the guide →What you will feel
Carrying way
A 7-tonne yacht has no brakes: in neutral at 2 knots she carries on for about 15 m. That is why you manoeuvre in neutral and in short bursts.
Prop walk
Going astern, the stern walks to port (right-handed propeller). It helps or hinders depending on which side you put to the quay.
The rudder needs water flow
Stopped, she will not steer, except with prop wash going ahead. Astern she steers the other way, and only once she has sternway.
The wind
Stopped, the boat lies beam-on and the bow falls off downwind. The motor boat, with no keel, drifts far more than the yacht.
Prop wash on the rudder
Stopped, with the helm hard over, give a burst ahead: the water from the propeller hits the rudder blade, the stern kicks one way and the bow swings hard the other way before the boat starts moving. It is how you turn a boat in a tight space.
Twin engines
One engine ahead and the other astern spins the boat on the spot. Leave the helm amidships: motor-boat rudders are small and at harbour speeds they do almost nothing; you steer with the engines.
Then do it for real
Manoeuvring lessons on BELA
What you do here with your finger, in Port Garraf you do with the real boat and Ricard beside you: berthing, springing off, stern-to and bow-to in whatever wind there is. €250 for a 2-hour session.
FAQ
Is the simulator free?
Yes. It runs in your phone or computer browser, with nothing to install. Berthing alongside works without signing up; the other manoeuvres unlock for free with your email. It is also inside the free Skipper app.
Which manoeuvres can I practise?
Five: berthing alongside in a gap, coming alongside the fuel dock starboard side to, bow-to mooring, bow-to with two free berths and a crosswind, and stern-to (Mediterranean) mooring. Each with wind from different directions, from 0 to 25 knots.
Is it realistic?
The yacht is modelled on a 10 m, 7-tonne cruiser with a right-handed propeller, like BELA, the school boat: she has inertia, prop walk, a rudder that only works with water flow, and gusty wind. It helps you understand the manoeuvre; the real boat behaves much the same, but the sea always surprises.
Does it help with the Spanish PER licence?
It helps you arrive at your practical sessions knowing what will happen, but it does not replace them: the PER requires compulsory practical training on a school boat, and harbour manoeuvres are learnt by doing them. At Altair we do them on BELA, in Port Garraf.
How do I control it on a phone?
You turn the wheel by dragging it round with your finger (double tap to centre it) and push the throttle up for ahead and down for astern. On a computer the arrow keys work too.
Want to understand prop walk before trying it? We explain it in propeller effect in manoeuvres.