232 GULFSTREAM/ SINGLE OX66 250HP PROP SELECTION.

[gju42486]

Im in the process of finalizing a deal on a 1998 grady white 232 gulfstream coming from Va and will be converted to a Lake Erie walleye trolling machine. I just had the boat surveyed with no major issues noted, just a few small cosmetic blemishes and some misc equipment needing replaced or fixed. I got a pretty good on the rig so i cant complain.

I know many have said that the single 250 is "underpowered" but i have no need to run 45-50mph at WOT as most of my runs are less than 15 miles one way.

On the survey, they conducted a fullpower trial and had the boat at 28knots/5300rpm's (according to the in dash gauge going off an old school paddlewheel). I have read some reports where people were able to get 35-37mph out of them at WOT. The owner is not sure of the prop specs currently, just that it is a 3 blade ss. To me, it seems like this boat should be pushing more than 28 with the light gear load that it has on board currently.

A buddy of mine stated that when his dad had this same boat/engine config that originally the engine was mounted to low on the brackett, when they brought it up a few inches the perfomance was alot better.

Just wondering what everyone else has noticed and if you believe this is average for this rig. Also, any prop advice to maybe pick it up to 35mph (if possible) would be a huge help.'

Im just wondering if the in dash mount isnt fully accurate, if the paddlewheel has growth on it not allowing it to spin freely ect.

 

[seasick]

Too many variables and not enough data. Regardless, you state the speed at 28 KNOTS. That is a tad over 32 MPH. The paddle wheel may not be accurate, you need a gps to be sure what the speed is. Knowing that the prop is a SS 3 blades tells us nothing. Knowing the diam and pitch would help.
You application is mostly trolling so what the fixation on top end? Top end is affected by many things, hull condition and slickness, fuel and gear load, passenger load, propping, rigging, trim etc.
Once you see how the fuel consumption jumps at WOT, you probably won't be running at it that often

 

[grady23]

Your speed should be a lot higher than 28. You could be having a problem with prop slippage at the hub. As stated -- To many vairiables like engine trim angle, trim tabs settings,age of fuel and so on....
My Gulstream w/twin 150's will make 48 MPH with 4 250lb+ guys, full load of gear and 150lbs of ice. I've seen others with your setup that can EASILY hit 42+.

 

[cobrapowersys]

I cruise at 28 knots top out at about 33 on my 268 islander w/ same OX66 250 motor boat full of gear and 4-5 guys. She is underpowered but that is more than enough for my fishing needs.

 

[Off doody]

My 1993 Gulfstream was repowered in 2005 with a Yamaha 250 4 stroke. The boat cruises at 25-26 mph and tops out at about 34 mph. I have to trim my engine up a bit to get more speed. If the engine is fully lowered it it pushes through the water more. Try trimming it up a little bit and see if you get a few more Mphs. Also the speed sensing tube can fill with debris and clog and not work properly. They can be cleaned out. A gps will be your most accurate speed sensor.

 

[gw204]

I was able to raise the motors (Yamaha 225s) two notches from the factory (lowest) setting on my old bracketed '93 Sailfish. At the same time, I went from the original 14-3/4 x 19 Yamaha props to 15-1/4 x 19 Merc Mirage Plus wheels and that combo made her run like an entirely different boat.

Hold a straight edge up against your hull bottom and see how it lines up with the anti-ventilation plate on your motor. Raising 2 notches on mine put the plates about 1.5" above the hull bottom and that seemed to be just about right. I may have even been able to go one step higher.

Get your motor height correct first, then start playing with the prop.