What size prop should I be looking for?

Zippydacat

Last year got a Sundeck Sport 188OB. Love the boat, but looking for better acceleration and performance. I really would like get a Stainless Steel Prop. I currently have a Mercury 115Hp outboard with the serial number77344A45 17P. What size should I be looking for? I am getting conflicting research results online as to go with a 13x18 or 14x17.

FlyingV5

Zippydacat, the answer is you'll have to experiment. A prop mfr. can make suggestions based on boat weight, horsepower, hull shape, etc. But the final determination will be: which prop allows the engine to run at about 95-100% of its rated max speed at full throttle without over revving. A 3 blade will typically give higher top speed, but a 4 blade may improve low and mid range performance enough to justify a trade-off of a few mph in top speed. Most prop vendors will allow you to test a prop and return it undamaged for the shipping cost if you decide you need a different one. Try to test them with conditions of smooth water and a light boat to see which one you like. My FD196OB lost 3 or 4 mph top speed but is a much better all around boat with a 4 blade prop. It planes out at lower speed and accelerates better now, and I really don't miss the extra speed since these boats tend to beat you up in choppy water anyway. And the SS prop won't bend a blade when I hit a floating stick.

camphermitage

I have a 188ob w/a 115 evinrude.  What prop did u purchase?  I have a14.5x19 top speed 43 at 5500 rpm.  When I add weight or tube no get up and difficult to plane. Looking for the right prop

dward0

camphermitage said:

I have a 188ob w/a 115 evinrude.  What prop did u purchase?  I have a14.5x19 top speed 43 at 5500 rpm.  When I add weight or tube no get up and difficult to plane. Looking for the right prop

Sounds like you need to pitch down an inch or two.