5 blade vs. 4 blade prop
 

How do you know when your application would benefit from a 5 blade prop? Is there some general rule or should you always just test both to be sure?

Re: 5 blade vs. 4 blade prop
 

If you're having trouble getting on plane with a 4 blade a 5 blade can help, also if you have high prop slip at mid-range speeds again a 5 blade can benefit by reducing the slip resulting in more speed. Typically a 5 blade will not be as fast on top end, but will make up for it in all other areas. I went to 5 blades and I'm very happy with their performance.

Re: 5 blade vs. 4 blade prop
 

I heard that 5 blades arent qiute as fast but they slice water a lot smoother.

Re: 5 blade vs. 4 blade prop
 

We tried them on our 35 Fountain, we saw the same as what Harper discribed. Got on plane easier, cruised 3-5 mph faster in the mid range, 3300-3800 rpm, but was 4 mph slower on the top end than the 4 blade. That was running Hydromotives P5 and 4 blade. Hydromotive said they can get the 5 blade as fast as a 4 blade but it would require labbing, deffusier ring adjustments ect. Have heard both that they are harder on drives and easier. Easier because they have less vibration because more blades in the water at once, and harder because they dont slip as much. Currently have 5 blade Maximus on our 38 Fountain with shorties, will start experimenting with props when the weather warms up a little. The biggest gains are in high slip applications, like cats with very high X's and when the blades are sufacing. If your props are not surfacing, its hard to beat a 4 Blade.

Re: 5 blade vs. 4 blade prop
 

Thanks for the information. The reason I am asking about 5 blades is because I am considering 2"shorties. Even with the x-dimension higher do you think that 4 blades will have the better top speed. Do the 5 blades make up for the slippage?

Re: 5 blade vs. 4 blade prop
 

Good info...thanks

Re: 5 blade vs. 4 blade prop
 

I just added 2" IMCO shorties to my 28 Daytona and will have to wait till it gets nice enough to try the p5x's to see what the shorties will do. Hopefully I'll pick up my rpm's on top enough to step up a pitch. On the down side, I hope I haven't gone up too high or I'll have to add a 1" spacer. I guess it's just a matter of experimenting to see what works best.

Re: 5 blade vs. 4 blade prop
 

The 5 blades are slower at top end but better at mid range and getting on plane as stated earlier,they raise the drives with the 5 blades to acheive similar top end as the 4 and still get on plane and have a better mid range.The 4 blade would probably be better at top end with a higher drive but you would't be able to get on plane

Re: 5 blade vs. 4 blade prop
 

Sounds as though I'll stick with the 4 blade for top end. I, too hope that I will pick up speed by going higher because I know I will have more slip. Guess there is no way to find out except by experimenting. Just trying to save some $ on the shorties if there is not speed to be gained.

Re: 5 blade vs. 4 blade prop
 

You guys keep this up and you won't need us on the board anymore. All very good information.

Testing is the only to ultimately know what will work the best for your set up. Maintaining the best efficiency with low drag is the key!

Re: 5 blade vs. 4 blade prop
 

Great job guys!

One of the pieces of information that is used to determine whether you are a good candidate for shorties is the measurement of the prop shaft in relation to the bottom of the hull and your current propeller slip. If you are on the high side with your slip and if your prop shaft is reasonable meaning not extrememly deep, then you may not benefit from shorties. It goes without saying that if your prop shafts are a 7inches below the hull then shorties indeed may improve your speeds.

Julie

Re: 5 blade vs. 4 blade prop
 

I have both... and they both work very well (for different reasons).

Consider this------ running in big water..... the more blades, the more stress on the drives. Run the 4's in big water and the 5's any other time.

that's my .02 cents!

Re: 5 blade vs. 4 blade prop
 

Sounds as though I will be running 4 blades unless the slip is too servere. I'll try the hydromotives and bravos back to back. If I go to the 1 1/4" vertical shaft in my shorties will I still have a good selection of props. What are the advantages of going to the larger shaft, other than durability? Any opinions on what others have done?

Re: 5 blade vs. 4 blade prop
 

Rebel
Have run both, the big prop shaft is a heavy piece, the advantage is if you do launch the boat you are less likely to twist the shaft when you re-enter. The 1.25 shaft also uses a billet carrier. Props are no problem, you just have to use the hub to fit the prop shaft. Most dealers carry them or you can get them from BBlades or Throttle-up. They are pricey though, but what on a boat isn't?????

Re: 5 blade vs. 4 blade prop
 

So the props that accomodate the larger shaft are more expensive? That along with the short vertical shaft ($630) might make it an expensive option x 2.

Re: 5 blade vs. 4 blade prop
 

The props alone aren't more expensive for a large shaft. What are you trying to do? Put on shorties? I just did this and it cost me approx. $4850 for both drives, that included the shorties, labor and new gear lube. The vertical shaft is part of the IMCO shortie kit, which will run you about $1900 for the kit.

Re: 5 blade vs. 4 blade prop
 

Yes, I am deciding on which way to go with shorties and more importantly will I see any speed gains with the shorter drives. The Bravo Shop lower units complete with a 1 year warranty sell for $3,380/each. Or, I can purchase the case for $1.680 and the vertical shaft for $630. Using my stock uppers. Best value?

I was leaning toward the Bravo Shop lowers because of the water pressure issues with the Imco's. How are yours working?