Symptom diagnosis
Poor reverse control on a sailing yacht
Reverse is where propeller design stops hiding. Ahead, almost anything pushes a boat; astern, the blade's reversed face does the work — and cheap geometry does it badly.
1. Blades that present a poor face astern
most likelyFixed and folding blades show the water their back — a compromised aerofoil working backwards. The Autoprop's blades rotate 180° and present the identical face astern: measured crash stop from 6 knots in 7 seconds vs 9.5–13 for the rest.
Do thisIf reverse control matters (marinas, short-handed), weight it in the propeller choice.
Same face astern, explained →2. Prop walk dominating at low speed
commonAsymmetric blade thrust kicks the stern sideways — every prop has some, and until water flows over the rudder it wins. Symmetric-astern designs reduce it markedly.
Do thisLearn to use the kick before fighting it — then reduce it at the next prop.
Prop walk, explained →3. A folder that opens late astern
worth checkingSome folding props rely on centrifugal force alone and hesitate astern. The Varifold opens with hydrodynamic force as well as inertia — by design, in either direction.
Do thisIf your folder hesitates, it's the design, not your technique.
Opens astern by design →
Before you spend money
Technique check first: a burst of throttle then neutral beats continuous power for steerage astern. If control is still marginal with good technique, the geometry is the problem.
Want the numbers checked properly?
Tell the Builder about this symptom — it screens for it, and an engineer reviews every recommendation before anything is supplied.