dreded 3 vs 4 blade...

[1976CV16]

I recently got some great tips on a previous thread however im looking for some specific or close to specific help to point me in the right direction. I have a 16 foot boat with an 85hp old v4 omc bolted high to a 6 inch jackplate. Loaded with no people is about 1500 pounds. Boat handles well loaded 4 people with a solas 13x19 aluminum 3blade but doesnt seem to have the torque to pull my kids on a tube comfortably. A no name brand 14x17 seems a bit better but still not good enough. I was advised to try a 12.75x17 4 blade for some good pulling power but dont want to spend more money and add more props to my collection. I was leaning more towards a 15 pitch 4 blade but still unsure. Can yall help save me some money? Fyi all aluminum i boat in shallow waters with trees and rocks so no ss.

 

[1976CV16]

I should add that speed and performance are of no concern, i just want to get up on plane and have the torque to pull the kids. Ill use the bigger 3 blade for cruising with the wife. Also i am have an induction tach hooked up but wont get to the harbor until friday to get the whole rpm at wot. I can red line it with more throttle to go just dont push it obvi

 

[Chris1956]

Gee, I cannot believe your issue is with the number of blades on the prop. I had my Merc V6 up on a jackplate and although it was good for cruising, it was bad for pulling a skier. Maybe the motor is too high or maybe the pitch of the prop is too high, or maybe the motor is not making the expected power.

 

[Georgesalmon]

Its really important that you keep your RPM's no higher than what is recommended by the manufacturer of your motor. When you get your tach you will be able to find out where your at with your current props. Until then everything is a WAG. However. for pulling kids that 15P 4 blade might just be the ticket. I'm real happy with the cost and performance of my Mercury spitfire 4 blade though I'm sure many other brands will also be good. By the way I also use two different props for changing uses of my boat. I use a 19P for just cruising around with two people and the 15P for water sports and Lake Michigan fishing with all the gear and two adults and four grandkids. Takes only a minute to change props in the garage. When I have the 15P four blade on its like I just shifted into four wheel drive.

 

[1976CV16]

I know im a bit lost without knowing the rpms. It sounds hilbilly but for 4 years of owning this motor i have gauged it by sound. I know i gotta stay within the rated redline which is 5500 for me however whats to say going too small will hurt anything? Why cant i put say a 13 pitch prop to get more hole shot than i could need and only have a top speed of say 20mph since.the redline will be more at half throttle? I know too high of a pitch will put stress on the motor but what does a small pitch do? So long as you dont over rev obviously. Low top speed and lots of pulling power. Thats my goal for this little motor

 

[Starcraft5834]

I use a 14.75x15p. Solas 4 blade on my 20ft cuddy w an "under powered" 3.0 140. Gives me lots of punch out of the hole.. 4500rpms. 31 mph

 

[1976CV16]

WAG... i had to google that one lol! I just ordered up a 13x15 4 blade solas aluminum. I dont mind if wot is over 5500, i just wont go wot. The only thing this prop will be doing is pushing the boat when fully loaded and pulling tje kids on the tube. A higher hp motor will probably do better with an all around prop but the smaller hp i think needs to take advantage of different props. For anybody else that keeps their boat in the water i highly reccomend a floating prop nut wrench and spare cotter pins and nuts. Im good for loosing atleast one screwdriver and wrench a year...