Propellers

[Ex Sailor]

There is a spare set of props that came with our boat. Both are stamped 24 - 21 but are slightly of a different shape.
Eg. One of the props has a straighter leading edge with a bit of a larger prop area ...... While the other, the leading edge is more curved.

Q. How important is the shape IF the numbers match ?

 

[mbevins]

They're not the same prop. They will perform totally different.

 

[Nomad Willy]

Most moern props are very similar so probably is not that important.

The blade area, #of blades and pitch are important considerations. Usually a 4 blade prop is better IF there's not enough blade area w a 3 blade that has a good pitch for your variables. Ideally the pitch should be close to .75 of the diameter numerically. Like 24X18. Most trawlers have big enough props so 3 blade props are best. But if you must get more blade area the 4 blade is the answer .. but only then IMO.