Better prop possible for Glastron GT205

diungerich

Seaman Apprentice
Joined
Sep 26, 2015
Messages
33
Thought I'd solicit some opinions. Boat runs well. Just wondering if I can get more. First, here's what I'm working with...

2007 Glastron GT205 (Spec says 20'8") Dry weight for the boat is supposed to be 2780lbs. 35gal tank.
5.0 Mercruiser (carbed) 220hp / Alpha 1 outdrive with 1.62 ratio

Current Prop:
Mercury Vengeance
48-16316-19P
Stainless 14" @ 19 pitch, I believe is it's spec.

So as it stands, performance is pretty good. It jumps out of the hole as it should, I think. About 3.5+ seconds to plane from dead stop. I can easily snap up adult skiers with 4 people in the boat. And I've pulled three teenagers on a tube with 2 adults and another teenager in the boat. No issues. WOT gets me around 4600-4700 RPM and about 46-47mph. Last test that I figured top end on was with 2 adults and one kid in the boat on pretty smooth but not glass water.

What I'm looking for...Don't want to give up anything on hole shot, better if possible. And on the top end, I would have thought I should be able to see 50+ without too much effort. Just wondering if I'm about where I should be or if there are props that I could squeeze some more out of this setup.

Note, the engine is running well. No issues or noises. Prop is in good shape, spins smooth, true, and quiet out of the water. Only thing in this area is it has what I'd consider a good amount of shift clunk when you put it in gear. That's an area I wish it were smoother. Wondering if I need to install something like Mercury's Flo-Torq SSR HD for shift clunk. Would appreciate thoughts on that too.

Thanks in advance.
 

SkiDad

Lieutenant Commander
Joined
Jul 18, 2010
Messages
1,518
47 is about all I would expect to see out of that boat. I don't think 50 is possible. You are setup about perfect in my opinion. Maybe a 19 pitch tuning point stainless. Check out Solas hub hits for clunk. If you must squeeze out a little more performance check Ken at prop gods out.
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Is your speed by GPS?
Your setup calculates very good. Looking for 3 mph when already close to 50 is a tough assignment.
If you have a folded Bimini top in the air ?? remove any unnecessary weight and passengers 1/4 tank of gas
etc Try covering the bow cockpit or perhaps uncover the bow.
Some one discovered that a pickup truck with the gate closed was more efficient than with the gate open.
These things are free and you may be able to say I made 50 but thats a stretch.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,296
I was running a 15 x 19P SS Solas prop on the SeaRay and hit 49.5mph on the GPS with just me in it. beyond that, you may need a bit more umph
 

diungerich

Seaman Apprentice
Joined
Sep 26, 2015
Messages
33
Thanks guys. It's not really about saying I can hit 50 or anything like that. Boat runs good and I'm not too worried about it. Really it was more of a case of "here's my setup. Think it good as it gets, or could I get more out of it." If I could drop a different prop on it and get both a better hole shot and some more on the top end (yeah, fantasy, I know), then awesome.

BTW, those numbers are with my bimini opened up. We have it up most of the time as long as it's hot out. And yes, I was checking with GPS (Waze on my phone).

Thanks for the feedback, guys.
 
Last edited:

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,296
Can't have both with a simple prop change. Usually you improve one at the expense of the other unless you add more power
 

Tail_Gunner

Admiral
Joined
Jan 13, 2006
Messages
6,237
Biggest improvement you could make would be a edelbrock intake and a 600 cfm carb that would change a few things up.
 

bluewater19

Chief Petty Officer
Joined
Apr 25, 2003
Messages
505
Try switching out the vengeance for a mirage plus, Same pitch, small vent holes..
I have a 2006 glastron 195sx with a wake board tower Volvo sx drive 1.60 / 5.0 GL 220hp and it hits over 50 on the GPS with 4 people and the tower/ bimini.
My boat came propped with a 21 pitch aluminum and I switched to a mirage. I had a whole rack of props from 19 to 23 that I have from old boats so I a had a few to chose from .Great hole shot but better top end.
 
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