outboard pitch question

[Katch]

I am asking this here since it pertains to ribs.
My outboard is a 1997 Evinrude 20hp 2-stroke. The stock pitch is at 13 incles according to the manual. Because I'm running it on a rib with a v-hull, do you think I'll get better performance with a 14 inch pitch? Not that I really need it since I'm getting 27mph with the stock; but I am just wondering if the stock numbers are not really ideal for a rib versus a regular boat.

I unexpectedly ran through some shallow mud on the Potomac yesterday, and while it didn't destroy my prop - it dinged up the blades a bit. Since I was planning to buy a spare prop, I may as well upgrade it if I can. I could used the dinged up one for my spare.

Thanks everyone

 

[Sea Rider]

Re: outboard pitch question

In order to play with prop pitches you must install a induction tach on your engine, go for a wot solo spin preferably on flat calm, no wind water and check max achieved rpm at full throttle. Compared those numbers against what factory specifies for mim-max rpm parameters at wot for your engine, then will know if running in the safe side.

Generally speaking standard factory delivered props are very good performers with light sib/ribs. Ideal rpm would be slight passing middle to near max rpm readings. Install tach, program firing sequence, check max numbers at wot, test will indicate if needing to go for a -, + pitch.

A 14" pitch will lower (200) top rpm achieved with 13", good if over reving, but that you don't know yet.

Happy Boating

 

[Katch]

Re: outboard pitch question

Being that my current prop is a bit dinged up (nothing bent-just the blades are no longer smooth around the edges); I wouldn't expect an accurate reading compared to a 13" prop in good condition. I'll try it anyway and see what kind of numbers show up. Now, I got to figure out how to install the tach