14 x 19 vs 15 x 19 ?

[zzrich]

The boat :Catalina Tahiti 21 1/2 (1983 model)
Motor : AQ260
Drive: Penta 280

I curently run a 15 x 19 rh aluminum prop. (hard to find) I know a guy selling a 14 x 19 prop. Will the smaller diamater make much of a difference ?

Also I am some what confused over which way these 280 drives are meant to spin. Folks on this board say to the right, the manual I have says to the left, a couple other people I have talked to say to the left as well. Not to sure myself.

Thanks for any insight here as it is a great help !

 

[steelespike]

Re: 14 x 19 vs 15 x 19 ?

Usually prop rotation is refered to as clockwise (C) or counterclockwise (CC)
looking from behind the boat. And may be included on the prop.Don't know Volvo rotation nor how they may label it. Certainly easy to tell by looking
at the blade configuration.
Diamater is usually not a primary consideration when selecting a prop it is simply a result of the prop design.If the the prop is listed for the motor and outdrive it should perform in approximately the same manner.
All that being said it wouldn't be a surprise if the larger diameter lowered the rpm slightly.Any time you change brands or designs you may get unexpected results.If you were testing for the best prop configuration you wouldn't try a 4 blade,then a 3, stainless then aluminum etc.You would try to establish a base line performanmce with one type & material then try different configurations to see what may improve the base line.The larger diameter may produce better low end performance.You wouldn't normally get a prop based primarily on the diameter.

 

[zzrich]

Re: 14 x 19 vs 15 x 19 ?

Good points steelespike. Right now its setup to run clockwise, but the prop has become weakened due to cavatation. Sounds like going down to 14" wouldnt hurt to much. The cool thing about these volvo penta 280 drives is that they can be switched from clockwise to cc with a simple linkage adjustment.