what prop should i be using?

[shvy]

Hay guy's
I have a 1989 23' bayliner 2302 with a 250hp mercury EFI saltwater outboard
It has a 140 gal. fuel tank (840 lbs.full), 50 gal. live bail tank (400 lbs.) and of corse me and other 3 @225 lbs. each (675 lbs.). right now i have a rapture stanless steel 14.25x17 prop. dont know the weight of the boat. it comes on plan ok, the wot is 5500 @39 miles per hr. and yes it use a lot of fuel. i used the boat for salt water fishing i souther california.

 

[boat1010]

Re: what prop should i be using?

I guess the question is why do you think you need another prop? I would think you could go up a little if you were looking for a little more top speed. I'm not sure what the manufacture WOT is for your boat but that seems a little high. So a little higher pitch would take care of that.

 

[hwsiii]

Re: what prop should i be using?

Shvy the boat shows weighing about 2,500 pounds and with the motor and everything else you said that means the weight comes in around 5,000 pounds. I also show the motor with a gear ratio of 1.75, but that doesn't seem right because at that speed I am showing a 23% prop slip and that is very high for that boat. What does the plate on it say for maximum weight and also what does the engine show for gear ratio. Would you take a straight board and push it up against the lowest portion of the bottom of the boat and extend it out to the anti ventilation plate and tell me how high the anti ventilation plate is above it. And it would be good if you could take a picture of the stick and anti ventilation plate at the same level as the stick. The 39 MPH seems kind of reasonable but the rest of it doesn't seem to work right. Is the speed you are giving us from a GPS or a speedometer.


H

 

[shvy]

Re: what prop should i be using?

i look for a hp & weight plate and could not find it. i will get back on the gear ratio and as for the anti ventilation plate and the bottom of the boat thay are even. i made sure when i repower my boat that i set it even with the bottom and have room to adjustment up or down. the speed was from the GPS. the tag on the motor is for 5500 WOT. im not looking for more speed just a better fuel per hr. as for pic im not sure how to make the pic smaller to fit.

 

[Dhadley]

Re: what prop should i be using?

If the prop really is 13 1/4" diameter that will account for a lot of the slip %. The 13 1/4" props were meant to be used on the smaller gearcases (4 1/4" case). Your 4 3/4" case should be using at least a 14" diameter prop.

 

[shvy]

Re: what prop should i be using?

my mistake it's a 14.25x17, the motor tage said max rpms are 5800, is that my wot? i just had my lowre unit reseal and replace the prop shaft it was bent, just put it togeather sunday have not been out yet.
thanks for the replay

 

[steelespike]

Re: what prop should i be using?

5,800 is your rated max.
It would seem your pretty close to the right setup.If you have no ventilation (cavitation)issues you may be able to raise the motor a hole or more.
Rule of thumb a motor uses 10% of its horsepower rating at WOT(wide open throttle)Your motor will use about 25 GPH(gallons per hour)atWOT.
Best cruising speed is generally between just on plane and about 2,000 rpm higher.

 

[shvy]

Re: what prop should i be using?

thank you Admiral and all for your feedbacks