reasons for prop slip
 

What are factors that cause excessive prop slip? I have a single step deep v with a notched transom with a prop shaft height of 4" below keel. My 26 bravo1 slips 24% at 3500rpm & 17% at 5100 rpm. I have a box stock 26 to test as I do not know history of current prop. But if I still have high slip #'s I need some ideas to look for setup flaws. Thank you

Re: reasons for prop slip
 

Here are a few reasons:

High X Dimension
Shorties
Improper propeller
Propeller that has been modified
Irregularities in the hull
Items hanging off of or below the hull


Julie

Re: reasons for prop slip
 

Thanks Julie, I will be testing the prop you sent me this weekend. I hope I will get better #'s with it & still have room to improve with labbing. Is 4' below keel considered a high x dimension? I will check the bottom again but I don't believe there is any hook in it. What percentage of slip is considered normal for a bravo 1?

Re: reasons for prop slip
 

On some deep V's 4" below can be considered high. On some stepped bottoms 4" can be considered low.

Normal slip is a tough question to answer. There really isn't a "normal" slip. We like to see deep V applications under 15% slip. Slip is also relative to the applications goals. If top speed is the target and slip climbs with with propeller work but so dose the speed. Slip is OK. One other consideration in high slip numbers is CG.

Re: reasons for prop slip
 

My single v 27 ft runs the fastest with 19-24% prop slip at max trim,always has. Every prop place I ever talked to told me it was too high BUT I have tried less pitch with less trim,just rpm's higher,goes slower and still won't eek out the last 5 mph until trimmed to the max throwing a rooster tail with a ton of slip. 4 " below hull is pretty high as far as conventional vee's,mine is close to 8" below hull. How good does it pop onto plane? You could try a drive spacer if looking for better take off and cruise but it probably won't help top end at all,Smitty