So if they are test props I would "assume" that the powdercoating does not change the performance of the prop relative to the polished finish. There are a couple of the designated "test" props here:

http://www.mrboats.com/specials.asp?cat=ACCESSORY

I think that they look cool. Do they come from merc in any other colors?

You will need 29 Herings to compare top speed against 28 Mercs. The six blades will give you added acceleration but will also give you more bow/stern lift depending on which direction you are turning them.

Thanks David,

So I would actually need a bigger size in the 6's over the 4 blade Merc?

No, it has nothing to do with the number of blades. Mercury's advertised pitch has always been one lower than the standard used by Hering, Rolla, etc.

Speaking of powdercoating.....

Ahh I see, thanks again David. Do you prefer Rolla over Hering?

Powerguy: Sorry, wasn't trying to hijack your thread.

dude if u can only turn a merc 28 4...there is NO way in hell your going to spin a 29 6 blade hering.

I definately prefer the Herings for most of the conditions we run in but also carry Mercury & Rollas for special situations.

Not necessarily true. Actually depends on diameter, blade thickness and boat setup.

How aggressively can you pitch a prop before it becomes inefficient compared to gearing up?

Roby

I have ask the same question robyw1 to every prop guy i have found and they all answer differently,