How to read propeller marketing

Propeller marketing has a dialect. Once you can read it, every brochure in the industry becomes clearer — including ours. Here's the phrasebook.

"Up to X%" — the direction is true, the number is a ceiling

'Up to 20% fuel saving' means at least one documented case reached 20% — it is not your guaranteed number. We use 'up to' framing too, because honest claims need it; the difference is we publish the underlying cases and mark the conservative figure first. Your number depends on your boat, and the calculator makes the assumptions editable.

Drag percentages without a baseline

'85% less drag' — than what, measured how, at what speed? Drag claims need a named baseline (ours: a fixed three-blade at sailing speed, per published independent testing) or they're decoration. Watch for comparisons against the worst possible strawman.

Efficiency at one magic RPM

Any propeller can be optimised for a single operating point — that's what fixed pitch is. The honest question is the whole curve: what happens at cruise, at motor-sail loads, punching weather? It's why our charts plot ranges, not one flattering dot.

Testimonial cherry-picking

Every brand has happy customers. The tell is whether the numbers come with boats, conditions, and the caveats — our owner stories each carry a 'what this doesn't prove' line, because one boat's result is evidence of possibility, not a promise.

The standard we hold ourselves to

Every chart on this site carries a MEASURED or MODELLED badge. Measured means a published test or logged trial, source named. Modelled means calculator output or an indicative curve, declared on its face. Where we hold only anchor points, we plot the points instead of drawing a pretty curve. Hold us to it — and hold everyone else to it too.