Prop size?

D

DonHof

Petty Officer 1st Class
Joined
Oct 19, 2009
Messages
318
I have a Lund with a 30 hp 4 stroke, it came with a 9 3/4 x 11 prop.
RPMs are 5800 at wot, the book said, max 6250. Is this OK?
Or should I be using a different prop?
Boat 585 lbs
6.5 gals of gas, two batteries ? lbs.
Wife and I 325 lbs.
I get about 25 mph by speedometer don't hae GPS.
This is all new so bear with me.

Thanks
Don
 
S

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: Prop size?

You did pretty good.I would be interested to see the rpm and speed by your self.
Speed seems reasonable.Some cell phones have a gps app.
What brand of motor? Do you have the rpm range?Usually it is suggested to prop close the the
max rpm but that would depend on if there seems to be a lack of performance.
Also may be possible to refine your setup for a little more speed and rpm.
Not that you need more speed but usually if you get setup for the best speed overall performance tends to be better.
Are you happy with the performance? Have you adjusted trim for the best top speed?

Are batteries and gas all in the back?
 
D

DonHof

Petty Officer 1st Class
Joined
Oct 19, 2009
Messages
318
Re: Prop size?

Seems speed and RPMs are about the same with me or both.
Don't do cell phones
Motor is a merc EFI, 2010
RPM range wot 5250-6250
Batteries and gas are in the back, no way to move them up as it
has a floor, there are compartment up front.
The 25 mph is with the motor trim up a bit.
 
P

pootnic

Chief Petty Officer
Joined
Aug 11, 2007
Messages
447
Re: Prop size?

Your fine.
Like SS is getting at, you may be able to get alittle more preformance by tweaking things around.
Weight,engine height play a real big role in small aluminum boats.
Props of course as well but your the 5800 rpm seems fine.
What size Lund,semi V?
Are you using a tiny tach?
 
D

DonHof

Petty Officer 1st Class
Joined
Oct 19, 2009
Messages
318
Re: Prop size?

It a 14.75 foot, semi v, and using the tach that came with the boat.
Everything is factory. Guess I won't mess with it, just thought I could
get a little more speed out of it.

Thanks for the help
Don
 
S

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: Prop size?

A 625lb Lund 1625 classic tiller did 29 mph Its not clear how much total weight. 11" prop at 5660.
Motor was mounted in hole 2. 25 isn't slow and gps could actually be more. but it does seem you might get more.
You might raise the motor one hole.
 
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