prop question, 3 to 4 blade.

[Alwhite00]

1986 Sea Ray Seville 210 MC (Mid cabin) Right now I have a 260 Mercruiser / Alpha 1 - 14.25 X 21 three blade aluminum prop. RPM tops out around 4,500, Cruise at 25mph @ 3,300 - 3,500 - Tops out at 40 mph.



I need to get this pig out of the hole quicker - Works OK when just 4 people on board but any more than that and it really struggles.



I talked to a guy tonight that has a near new Rubex Solas 14.25 X 19 four blade stainless prop for sale at a good price, I need to buy a hub kit for it (he said $52.00) I am thinking this is what I want but I can not find this prop listed on their website, I will try & get a P/N tomorrow.



I believe I am to go down 2 pitch numbers going to a 4 blade, Is this correct?



I believe this is what I want but would like some input if anyone has any.





Thanks



LK

 

[Bondo]

Re: prop question, 3 to 4 blade.

Ayuh,... It sounds like yer headed in the Right direction,...

Ya need to get the rpms up, 'n a 2" drop oughta do it...

 

[not enuf toys]

Re: prop question, 3 to 4 blade.

sounds like you need to be at 19 pitch for a 3 blade (2 in drop will raise the rpms 200 - 400)

going to a four blade should be 1 in drop from normal - your normal should be 19 - look at 18 in four blades

4 bbl or 2 bbl?

if 4, you are missing your top end power

 

[skippy2235]

Re: prop question, 3 to 4 blade.

So I also have the same issue. I talked to the local prop guy and he said, yes. The four blade only gives one pitch, but with the extra blade you will loose 10 MPH, and with the extra blade you will get a lot more hole shot, and more drag.
Is this correct?

 

[Alwhite00]

Re: prop question, 3 to 4 blade.

260 hp 4 BBl - Alpha 1

LK

 

[not enuf toys]

Re: prop question, 3 to 4 blade.

i also have a 260 4bbl with 1.47 drive
when i run my 21 3blade i run round 57 58 at 4300ish rpms

when i dropped to a 19 3 blade i was able to get the rpms up to 4800 where they should be and the motor sounds much better...doesnt seem to be bogging. i lost 3 mph on the 3 blade but was worth it for the whole shot.

i ultimatley ended up with a 19 5 blade. hole shot is amazing!!! lost a total of 4 to 5 mph when loaded with people but holeshot is still maintained!!!