Props - 3 blade to 4 blade swap

[buoy37]

We have a small 15 foot boat that (in my opinion) takes way to long to get up on plane. After it gets on plane, it starts to porpoise. The motor is a new 30 horse ETEC with a 3 blade 10x12P stainless prop. Should I exercise all of my options with a 3 blade before switching to a 4 blade. Moving fast is not priority. Getting up on plane at a low RPM is.

[svs]

A cavitation plate like a Shaw or a Shallow Blaster should help with both problems.

[Rollo]

A cavitation plate like a Shaw or a Shallow Blaster should help with both problems.

Fixen to put one on my boat,I believe it will make a good improvement in both catogorys....We could check with Bauman!

[corndog]

See if you can borrow a four blade prop to try out. I might go back to the dealer and ask them what the heck? I mean if the tilt and jack plate are all the way down the boat should not porpoise if set up right.

[buoy37]

No interest in going back to the dealer. Our last experience with the dealer was not good. I'll keep the story off the forum because I don't know all the details. I want to try and fix the situation on my own.

I feel the jack plate is too heavy. I will be taking the CMC off and replacing it with something half the weight like the Atlas Micro Jacker. Secondly, I would like to try and reprop the motor instead of adding a cavitation plate. I will be reaching out to the sponsors soon. I just wanted to hear some of your thoughts.

[Beandaddy]

The right pitch and trim angle should do it. In my opinion you would waste horse power with a 4 blade.
Beandaddy

[FishNette]

If it's trimmed all the way in, and down, it should plane rather quickly. I agree 100% with installing a cavitation plate. There is no other modification for your boat that will cure the slow planing issue quicker. I have installed one on every boat I have ever owned. The best money you'll spend. Save the money on the new jack plate. Weight is not the problem, IMO. A lack of horsepower may also be contributing to this problem. Your seating position is definitely contributing. Do the cavitation plate first. You'll be glad you did.


As far as props go, a 4 blade prop is more suitable for a good bite(less cavitation) closer to the surface of the water, and while making a turn, than a 3 blade. 5 blades even more so. If you're gonna run skinny, with the motor up, the more blades the better. Be sure to reduce the pitch as you add blades, or you'll end up with too much prop for the motor to spin at higher rpm.


Hope this helps! Good luck!

[Rollo]

Seems like a little more boat than that engine can easily deal with, The right prop can help with lift off so to speak,Porposing is a differant problem.A cavitation plate could eliminate this issue,It focuses the water around your prop and will give control!

[buoy37]

If it's trimmed all the way in, and down, it should plane rather quickly. I agree 100% with installing a cavitation plate. There is no other modification for your boat that will cure the slow planing issue quicker. I have installed one on every boat I have ever owned. The best money you'll spend. Save the money on the new jack plate. Weight is not the problem, IMO. A lack of horsepower may also be contributing to this problem. Your seating position is definitely contributing. Do the cavitation plate first. You'll be glad you did.


As far as props go, a 4 blade prop is more suitable for a good bite(less cavitation) closer to the surface of the water, and while making a turn, than a 3 blade. 5 blades even more so. If you're gonna run skinny, with the motor up, the more blades the better. Be sure to reduce the pitch as you add blades, or you'll end up with too much prop for the motor to spin at higher rpm.


Hope this helps! Good luck!

Awesome!!! Thank you for taking the time to share your knowledge.

[Beandaddy]

Put a 70 on it.

[buoy37]

Put a 70 on it.

In hindsight, I wish I would have hung a 40 back there.

[buoy37]

Loss weight .

It is my wife's boat. I'll pass on the advice.

[evansmarine]

4 blade is always going to be better out of the hole and still needs proper pitch, diameter and cupping. Lot of people know as well whith the 4 blade you will loose about 400 rpm on top end if comparable to the same pitch diameter, and cupped 3 blade propeller. Louie on here is the man with major knowledge of what you would want to run on the boat. Also a 4 blade you will loose reverse power considerably.

[evansmarine]

In hindsight, I wish I would have hung a 40 back there.

irf its carbed just cange to 40 jets and hotter plugs, you will get more power. But looking at the rig, the 30 if set up right should move that boat around 27-30MPH.

[evansmarine]

I guess your about to find out Paul, we jus made your Yami 70 a 90