Think I've decided..opinions please

Matt S

Seaman
Joined
Dec 26, 2006
Messages
71
07 Glastron 185, 3.0L volvo. Stock prop is aluminum 14 1/4 x 21. Just want to bounce my knowledge off the experts!

So after all the reading here I am guessing that it's 14 1/4 diameter, 21 pitch.
If I go to a 20 pitch, rpm's go up by about 250rpm.

If I go 4 blade, I have to drop 1" diameter, so about 13" x 21 and I'll lose a couple mph at the top end (?).

Desired result: Have a prop to put on when the boat had 4 people and a tuber or skiier. Achieve 30mph without going above 4k rpms, i.e. not close to wot.

With 2 small people, a dog and full tank I'm currently hitting about 30mph around 3,200 rpm. From a stop, WOT gets me 3500rpm until on plane, and then it's 4500 @ about 45mph. 30mph is comfortable and plenty fast enough for me in usual choppy conditions (average saturday afternoon lake with light wind). With 4 people and a full tank, I'm at about 41mph at 4500rpm.


Question: Will I be happy with a 3 blade 14 1/4 x 20 for hole shots or should I go 4 blade 13x21...or 4 blade 13x20? Or go to a 19pitch 3 blade? Thoughts are appreciated!
 

WillyBWright

Fleet Admiral
Joined
Dec 29, 2003
Messages
8,200
Re: Think I've decided..opinions please

The 13" diameter range sounds inappropriate for a sterndrive. Are you sure that isn't an outboard prop for less than V-6s?
 

Matt S

Seaman
Joined
Dec 26, 2006
Messages
71
Re: Think I've decided..opinions please

From what I (thought) I read, I need to go down an inch in diameter with a 4 blade prop. Is that not true?
 

Tail_Gunner

Admiral
Joined
Jan 13, 2006
Messages
6,237
Re: Think I've decided..opinions please

In a boat that size with a 3.0 id say more in the 18 pitch range, do you know the type of 4 blade your thinking of buying? Currently im running a 20 pitch 4blade on a 186 with a 215 hp v6 I/O wieghing in @ 3000lbs and it run's @ 4900 @ wot, our boats are quite similar id say a 20 on 3.0 would be a bit much....

Ive also ran a 20 4blade on a 17.5 with a 3.0, it could barely pull 4600 rpm with only 1 person,
 

Matt S

Seaman
Joined
Dec 26, 2006
Messages
71
Re: Think I've decided..opinions please

I haven't narrowed down a type yet. I'm not sure what the manufacturer differences are but looking on the inexpensive side but I really don't know. But that's good comparison info thanks.
 
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