Trying to understand props

[lakelover]

I know this sort of thing has been discussed before, but if someone could humor me with an answer, I'd sure appreciate it.<br /><br />I have a 14' aluminum Starcraft with a 20 hp Merc with the standard propeller, 10 3/8 x 13. Usually it's just me, the anchor, the gas tank, the tool kit, oars and a PFD. Top end GPS is 29.1 mph.<br /><br />Would going to a 10 1/4 x 14 1/2 prop increase or decrease my top end? I'm trying to understand the relationship between dia/pitch etc.<br /><br />Is there a good article somewhere that explains it all?<br /> <br />Thanks.

 

[roscoe]

Re: Trying to understand props

IF the motor is currently operating OVER the manufacturers recommended rpm, then going to the higher pitch prop will lower the rpm and increase your speed "slightly"(1-2mph).<br /><br />If you are now operating at or below the recommended rpm, the high pitch prop will lower the rpm even more, putting additional stress on the engine, and probably not helping your top speed.<br /><br />Your best performance and engine longevity will come when you use the prop that will let you reach the recommended rpm (approx 6000)at wide open throttle (WOT).<br /><br />Since you probably don't have a tach on your 20, its kindof a guessing game. Iwouldn't mess with it for maybe 1 mph.<br /><br />More info:<br /><br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=36;t=000015 <br /><br /> http://www.boat-props.com/prop_basics.html <br /><br /> http://www.boat-props.com/prop_rpms.html#1

 

[lakelover]

Re: Trying to understand props

Thanks, and thanks for the links.

 

[cobra 3.0]

Re: Trying to understand props

You could get yourself a tiny tach and know exactly what your rpms are:<br /><br /> http://www.tinytach.com/

 

[rodbolt]

Re: Trying to understand props

hello<br /> try to understand women. its easier and more books are out on that subject.<br /> good luck and keep posting

 

[boatin]

Re: Trying to understand props

Rodbolt.. Women are easier to understand than props?????????Maybe you could link us to some of those books!

 

[roscoe]

Re: Trying to understand props

I hear some of those books have pictures.

 

[lakelover]

Re: Trying to understand props

try to understand women. its easier and more books are out on that subject.<br />good luck and keep posting

You understand women only when you give up trying to understand them. Props easier, I think