Need top speed
08-05-2004, 02:06 PM
#1
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Need top speed
I have been reading threads from offshoreonly for a while, and have decided this is the best place to look for help.
I have been boating in Nebraska for years. Mostly with a 19' Sea Ray. NOT a high performance boat by any means, but fun and very reliable.
After a profitable last year, I decided to go out and find a good boat for speed and power. Living on a 300 acre lake with a 23' restriction on length, my options were slim. I would love to get a second mortgage and a 38' boat with multiple engines, but I would not be able to use it on the lake I live on.
After shopping for a while, I found what I thought was the perfect boat.
I found a 1999 23' Wellcraft Excalibur with a 502 Mag (Bravo 1 1:50).
With straight pipe 4” exhaust straight out the back, I could hardly wait to get this boat out and see what it would do.
To make this long story short, I have been very unimpressed with the performance.
The first time I took it out I had the stock 23 pitch mirage on and ran 61 mph at 4900 rpm. I was not satisfied.
I then borrowed a friends 25 pitch 3 blade prop (14 ¾”). I later realized that it was a Yamaha outboard prop, which some people said I could use, but should be careful. I was by myself, still had a good whole shot and quickly reached 69 mph. I was excited and already thinking about another prop, when the overheating alarm started to go off. After some trial and error I figured out that the impellor in the water pump was shot. I replaced this with a knowledgeable friend.
Again excited about the top speed, went out and could not get the boat over 58 mph. It is only running 4100 rpms, and I can not figure out what has happened. I verified the top speed on a GPS and it is correct. I also put the old 23 pitch back on, and got the exact same results. It is like I am only getting 75% of the power I should be.
The boat is 3800 lbs dry weight and 22’ 9” long. With 425 hp I’m not happy.
Again, I am new to all of this, and would appreciate any advice.
Does anyone have any suggestions for my need for speed?
I have been boating in Nebraska for years. Mostly with a 19' Sea Ray. NOT a high performance boat by any means, but fun and very reliable.
After a profitable last year, I decided to go out and find a good boat for speed and power. Living on a 300 acre lake with a 23' restriction on length, my options were slim. I would love to get a second mortgage and a 38' boat with multiple engines, but I would not be able to use it on the lake I live on.
After shopping for a while, I found what I thought was the perfect boat.
I found a 1999 23' Wellcraft Excalibur with a 502 Mag (Bravo 1 1:50).
With straight pipe 4” exhaust straight out the back, I could hardly wait to get this boat out and see what it would do.
To make this long story short, I have been very unimpressed with the performance.
The first time I took it out I had the stock 23 pitch mirage on and ran 61 mph at 4900 rpm. I was not satisfied.
I then borrowed a friends 25 pitch 3 blade prop (14 ¾”). I later realized that it was a Yamaha outboard prop, which some people said I could use, but should be careful. I was by myself, still had a good whole shot and quickly reached 69 mph. I was excited and already thinking about another prop, when the overheating alarm started to go off. After some trial and error I figured out that the impellor in the water pump was shot. I replaced this with a knowledgeable friend.
Again excited about the top speed, went out and could not get the boat over 58 mph. It is only running 4100 rpms, and I can not figure out what has happened. I verified the top speed on a GPS and it is correct. I also put the old 23 pitch back on, and got the exact same results. It is like I am only getting 75% of the power I should be.
The boat is 3800 lbs dry weight and 22’ 9” long. With 425 hp I’m not happy.
Again, I am new to all of this, and would appreciate any advice.
Does anyone have any suggestions for my need for speed?
08-05-2004, 02:21 PM
#2
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Location: Cincinnati, Ohio
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Re: Need top speed
25 pitch prop is too big, the motor can't turn it enough rpms.
The 69 can not be right, that is where the problem comes in. My GPS screws up every once in a while if I hang a U-turn at fast speeds.
23 pitch prop at 61 mph at 4900rpm is 14% slip probably normal for the boat.
25 pitch prop at 58 mph at 4100rpm is the about the right speed.
I would expect it to be a little faster but not much 63-64, most wellcrafts like three blade props so you will probably want to stick with it. Have the three blade prop labbed and you will get an extra 1-2 mph. other then that motor upgrades or procharger is the only way.
The 69 can not be right, that is where the problem comes in. My GPS screws up every once in a while if I hang a U-turn at fast speeds.
23 pitch prop at 61 mph at 4900rpm is 14% slip probably normal for the boat.
25 pitch prop at 58 mph at 4100rpm is the about the right speed.
I would expect it to be a little faster but not much 63-64, most wellcrafts like three blade props so you will probably want to stick with it. Have the three blade prop labbed and you will get an extra 1-2 mph. other then that motor upgrades or procharger is the only way.
08-05-2004, 02:39 PM
#4
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Re: Need top speed
Smaller are easier to turn but don't push as much water. I would talk to Darin at Houston Prop, he is on here all the time. He can tell you what to do on a prop.
