Every performance figure on this site has a file behind it. This page is the public index — kept deliberately boring, per ACCC guidance that advertised claims must be accurate and provable.
Basis: Company engineering guidance across documented fitments; independent bench test measuring 6 kn at ~2,100 rpm (Autoprop) vs ~2,500 rpm (standard fixed propeller).
Wording policy: Published as 'typically 300–400 rpm lower at cruise vs a fixed prop'.
Basis: Company rule-of-thumb supported by the Voiles et Voiliers consumption trial (best in test at 6 kn), documented owner results in the 15–30% band, and one long-term magazine test owner reporting >30% on a 75 hp Yanmar.
Wording policy: Published as 'up to 20% — some owners report more', always with the band and the calculator's assumptions panel.
Basis: Published independent drag testing: feathered drag ≈ 5–10% of a fixed propeller's; folded lower again; manufacturer-published ≥85% reduction for feathered blades vs fixed 3-blade.
Wording policy: Published as 'worth up to a knot' with the comparator named.
Basis: Blade geometry: blades rotate through 180°, presenting the identical cambered section in reverse.
Wording policy: Mechanism stated; demonstrated at sea trial.
Independent controlled tests rank highest, then controlled sea trials, then dealer before/after trials, then owner-logged data, then testimonials, then engineering estimates — each labelled as what it is wherever it appears. See the evidence library for the sources themselves.