grady 232 gulfstream single 250 yamaha

Sounds about right to me. I have a Voyager 248 with a single yamaha 250. 28 miles and hour at 4500-4800 depending on load.............
 
I've got the identical set up. The boat really struggles with a full load of fishing gear and 140 gallons of fuel. I have thought about an upgrade to the 300. Will there be a sacrifice in range and fuel burn? At this point I can't justify the cost vs. benefit. Better off upgrading to a larger boat with more range at some point in the future.
 
3 blade to 4 blade prop

Original 3 blade 17 pitch prop that came with the boat and motor resulted in the following according to my load, gps, and floscan gauge
Moved to the Powertech ELE 4 blade 15x15 and got the following
3 Blade 17 pitch
RPM KNTs MPH GPH MPG
1000 4.3 4.9 1.2 4.12
1500 5.7 6.6 1.8 3.64
2000 6.7 7.7 3.1 2.49
2500 7.3 8.4 4 2.10
3000 8.3 9.6 5.5 1.74
3500 10.6 12.2 6.7 1.82
4000 20.1 23.1 8.8 2.63
4500 24.1 27.7 11.4 2.43
5000 26.9 31.0 13.3 2.33
5500 29.2 33.6 17.8 1.89
WOT 30.5 35.1 18.9 1.86

4 blade 15x15
RPM KNTs MPH GPH MPG
1000 4 4.6
1500 5.7 6.6 1.8 3.64
2000 6.6 7.6 2.7 2.81
2500 7.5 8.6 3.8 2.27
3000 8.4 9.7 5.2 1.86
3500 9.7 11.2 6.7 1.67
4000 12.1 13.9 8.4 1.66
4500 19.5 22.4 9.1 2.47
5000 24.6 28.3 11.5 2.46
5500 29.7 34.2 15.3 2.23
WOT 31.5 36.2 19.7 1.84
 
moved from the 3 blade 17 pitch prop to a 4 blade powertech ele
next step is to move the motor up two holes


3 Blade 17 pitch 4 blade 15x15
RPM KNTs MPH GPH MPG RPM KNTs MPH GPH MPG
1000 4 4.6 1000 4.3 4.9 1.2 4.12
1500 5.7 6.6 1.8 3.64 1500 5.7 6.6 1.8 3.64
2000 6.6 7.6 2.7 2.81 2000 6.7 7.7 3.1 2.49
2500 7.5 8.6 3.8 2.27 2500 7.3 8.4 4 2.10
3000 8.4 9.7 5.2 1.86 3000 8.3 9.6 5.5 1.74
3500 9.7 11.2 6.7 1.67 3500 10.6 12.2 6.7 1.82
4000 12.1 13.9 8.4 1.66 4000 20.1 23.1 8.8 2.63
4500 19.5 22.4 9.1 2.47 4500 24.1 27.7 11.4 2.43
5000 24.6 28.3 11.5 2.46 5000 26.9 31.0 13.3 2.33
5500 29.7 34.2 15.3 2.23 5500 29.2 33.6 17.8 1.89
WOT 31.5 36.2 19.7 1.84 WOT 30.5 35.1 18.9 1.86
 
I can't help much but I saw a review on a new 232 with a Yamaha 350hp V8. I believe they said it roped at 51+ mph.
https://youtu.be/oZTGqwykiGo

I have a 1990 230 gulfsream with twin 2000's 150 Johnson carbed 2 strokes. My props are actually different from each other at the moment and I top out at just under 47 mph.
 
It looks like the 4 blade is slowing you way down in the cruise range. We'd definitely be curious how you end up for motor height on the bracket. Mine seems low.
 
I cruise at 4500 so the speed has actually increased and the true benefit was right at 4000 rpms. That is probably a more realistic cruise on the open Atlantic anyway. Very few flat calm days. Will let you know the new numbers when I raise the motor
 
You are doing a little better than me. I took about a 70 kt mile trip Saturday. at 4500 rpm I'm running at almost 20.0 kts exactly. The boat feels great at 47-4900 but that seems to aggressive for fuel burn and long term motor life. Another 50 HP, or the 4.2 L 250HP would likely be ideal.
 
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