View Full Version : 4 Blade on Single OB Offshore vs. 3 Blade

05-10-2017, 09:59 AM
Advantages of 4 blade over 3 blade on a single OB offshore? I'd particularly like to have a little slower planning speed and transom lift.

Key West 203FS - no Ttop or trim tabs (typical high sided center console)
175 Zuke - 15 x 21" Yamaha SSII 3 blade

Holeshot is fantastic. Does not break loose even in rough water. Slowest planning speed is 18mph (even when loaded) and comfortably cruises at 25mph a few ticks over 3k.

BUT --- Bangs the limiter even when loaded and trimmed.

For propping of 2 strokes, the rule of thumb I've always went with was prop for max RPM lightly loaded as they will come down with load. This is odd though as its my first 4stroke. It seems the dealer just threw one on, and could probably use either a 22 or 23". How would the 4S like the extra lugging in the lower rpm range?

Overall pleased with the performance and the wife loves it. I'm just always thinking about little things and was wondering if a 4 blade would help especially when the water gets a little snotty by lifting the stern. At this point, I'm not going to install tabs.... just yet. A quality 4 blade is a big investment and not sure if the performance would be worth the cost.

Please advise.

05-10-2017, 01:39 PM
Better yet, anyone around the Pensacola - Gulf Shores area have one I can borrow? 15x21 or 19 / 4 blade.

Naturally, I own it if any damage were to occur and will sign an agreement as to the cost beforehand.

Magcat 62
05-10-2017, 07:36 PM
I HAVE a 23 ccbay runner w/ 175 4stroke zuki 15x21 suzuki ss prop double-cupped. proved to be best prop gear ratio is 2.5-1. brute power all around. revs about 5600 WOT JUST add some cup bet youll like it made a big improvement for less than 100 bucks. im not a 4 blade guy just more drag and weight ,imo ART

05-21-2017, 05:26 AM
What is max speed and at what rpm.
No point just saying it is hitting limiter as it might not be.
And at what speed do you want it's slowest plane to be.
DO NOT FIT TRIM TABS. They are just a way to ruin a transom.
Is this motor on a jack plate ?

W2F a V-King
05-21-2017, 06:15 AM
I have run both 3 and 4 blade props over the years. To say one is better than the other, it is different for each situation.

My experience is with a heavy 23' cc offshore open fish, I had a pair of Merc 2.4 200's counter rotating LU's.

Tried a bunch of combinations, 3 blade chopper gave the bow lift, and the boat was already heavy at the stern. Standard props, did OK but I was searching for slower planing speeds and stern lift like you. Ended up with a pair of counter rotating 4 blade cleaver's over the hub exhaust props 14.5" X 22". I managed 66 mph GPS with it unloaded and two people, turning a about 6300K.

Hole shot was great, lifted the stern and went. The boat was kind of stern heavy anyway, full transom and twin brackets, dive platform, etc...

I had a set of bennett trim tabs on it and other boats as well.
Imho they prove to be a big help to control boat attitude in rough water for the best ride with any given load or water conditions, to putting one side up a bite to minimize spray on a cross windy day. Load a few people on board and they don't set just right to even out the load...touch the joy stick and the boat rides how you want it to.

Wish I lived closer, I still have those props, and the RH one would be worth a try.


06-07-2017, 11:33 AM
I like big diameter 3 blade - I have 4 blade and 5 blade- big 3 blade on the torque heavy Merc F150 works well on my Mako 235 (23' @ 2400 lbs dry weight)