4 BLADE PROP VS 3 BLADE PROP

[CROOZY]

HI ALL, I HAVE A 2003 YAMAHA 200 4STROKE WITH A 17" PROP ( A LITTLE UNDERSTATED I THINK, OVER REVING BY 100 RPM) I AM LOOKING TO PUT A 3 BLADE 19" OR AS HAS BEEN SUGGESTED A 4 BLADE 17" ( SLOWS THE REVS A BIT), HAS ANYONE HAD ANY EXPERIENCE IN THIS AREA, IN PARTICULAR 4 BLADE PROPS, IS THERE A NOTICEABLE DIFFERENCE ?? # #CHEERS CROOZY

[Spaniard_King]

Croozy,

I have both a 3 blade 17 and a 4 blade 17 to use on my Honda 130 and yes the 4 blade will drop some revs out of it. What happens is the 4 blade takes more HP to drive it at the top end of the rev range so it will take some revs out of it about 150 for mine.

the 4 blade changes the boat somewhat in that it is a lot #more efficient in the water and makes the boat push through waves and chop where as with the 3 blade you get some slippage. It's not a bad thing just something to get used to

the other thing is you dont have to drive her flat out so just because it can rev that high dosnt mean you have to ;)



cheers

Garry

[the_bomber]

Which one do you tend to use more Garry?

[Spaniard_King]

Which one do you tend to use more Garry?


The 4 blader is by far a better prop in all conditions and is exceptional for bar crossing where you could end up in white water so it gets preference.

cheers

Garry

[Kendall249]

Using 14.1/8 x 23 4 blade (heavily cupped) , over 14.5 x 19 3 blade, less vibration and it doesn't want fall off the plane at low revs, though lost some top end as expected ( 400 rpm and 3 knots) but pulling 28 knts @ 4000 rpm and 32knts @ 5100rpm. #Have a 7.5m longboat and only used the new prop today for the first time. #Has made the boat handle alot better producing more thrust at low revs also keeping the bow higher and the boat dryer. #but will take it to prop rite to get it fined tuned. #That was in about 12 - 15 knot wind (sloppy in townsville waters). Can't wait (sort of) to try it in 20 -25 knts. # #

[Stu]

I use a 4 blade prop on an Allison 175 (same hull as the 189) with a 125 Mariner 2stroke.
Its the same pitch as the old three blade (17inch). It dropped a few miles an hour off top speed. Its still revs out to the rev limiter.
The main advantage is the extra "grip"in the water and low down drive. The boat can pane at lower speeds with less effort from the donk.
They are excellent for sea work.
I carry a spare 3 blade prop but have no desire to use it because the 4 blade prop is so much better.
I hang out on the north side of Moreton Bay which can be fairly rough at times (except during the week when I work ) so its a real advantage.
Cheers
Stu

[Stu]

thats plane not pane. :o Must get a spell checker.
cheers stu
;)

[Eagle]

Hi fellas
I notice that everyone who asks about using a four blade prop has an engine that is greater than twice the size of mine. My boat is a Bluefin Weekender and powered by a Mariner 60 hp 4 stroke EFI. I am thinking of fitting a 4 blade prop to the motor but have no idea about what size. Would fitting a 4 blade prop be an advantage with this size motor? The standard 3 blade prop is definitely lacking in performance. The motor needs to be reved out to around 4000 rpm to get the boat quickly up on the plane and at less revs it seems to lack thrust. Now that the motor has been run in (very carefully) it over revs at WOT on standard ULP. The revs available have increased since I swapped to standard unleaded fuel and ceased using the premium grade. I still run a tank of premium grade every 3rd or 4th tank to help keep the injectors clean but I'm not sure if I have to even do this. Any comments on props and fuel are most appreciated.
:-/
Eagle

[Chimo]

Hi Eagle

Have a go on the prop selector on this web site.

http://sites.mercurymarine.com/portal/page?_pageid=126,53050,126_53052&_dad=portal&_schema=PORTAL

I just tried it to check mine (115s Evinrude) and its pretty good

Also do a search on Dogpile.com (search) for
"4 blade vs 3 blade propellers?"

Theres heaps of good data there too

Cheers

Chimo