What is the difference between a 3 and 4 blade FeatherStream propeller?

The main difference between a 3 blade and a 4 bladed propeller is the motoring performance when motoring into strong head winds/choppy seas.

The extra blade area means propeller slips less and boat speed is maintained better in these conditions (increasing efficiency).

The other advantage of a 4 blade is that the extra blade area means much lower blade pressures, so less cavitation and therefore a quieter propeller (depending on hull type stern configuration). Stopping capabilities are often increased due to an increase in blade area (DAR).

When there is sufficient room for any size propeller, the case for choosing a 4 blade is really just one of a luxury rather than a necessity.

However, in cases where ideally we would be fitting a significantly larger propeller, the case for fitting a 4 blade is stronger because the same work can be done in a smaller diameter with a 4 blade. A heavy displacement hull form with increased wetted surface area will always benefit more from a 4B propeller where maximum grip on the water is required to maintain good hull speeds.

Posted on Thursday, July 28th, 2022