Max Speed Attainable with These Fgures

[champ20B]

i have got a pretty good reputation when it comes to testing and tuning race boats and motors i do a lot of my own custom stuff. I also do a lot of custom work for other people.i have the fastest flat bottom aluminum boat that i have ever seen.and i have come to the conclusion that i am no where near smart enough to hold a conversation with pdt or champ 20b much less try to talk about how to make a boat go fast. I've only been doing it 35 years and as far as i can see ya'll can do in 10 minutes with pen and paper what it has taken me a life time to figure out.

I have respect for those of you out there who have dedicated years to the quest for performance on the water. It is from guys like you of which I have learned what I know. I dont want anyone to think I am just some young smart-elic commentator. Im only in my 30s, but I have dedicated years to speed boats as well. It is a family tradition of over 50 years. I also learned about engines and racing from a man who started racing in 1927 and raced till 1958. He was a graduate of the Curtis Wright aeronautical mechanic school in the 1930s as well. I have a certificate in machining and had brought many antique motors to life that are still running years later. As for my method of speed calculations, I don't use pen and paper........

I use a graphing utility calculator hand in hand with my GPS.....and that is as precise as precise can get. Work smarter, not harder.

[MWhite]

I have respect for those of you out there who have dedicated years to the quest for performance on the water. It is from guys like you of which I have learned what I know. I dont want anyone to think I am just some young smart-elic commentator. Im only in my 30s, but I have dedicated years to speed boats as well. It is a family tradition of over 50 years. I also learned about engines and racing from a man who started racing in 1927 and raced till 1958. He was a graduate of the Curtis Wright aeronautical mechanic school in the 1930s as well. I have a certificate in machining and had brought many antique motors to life that are still running years later. As for my method of speed calculations, I don't use pen and paper........

I use a graphing utility calculator hand in hand with my GPS.....and that is as precise as precise can get. Work smarter, not harder.

Your only in your 30s and u have dedicated years to speed to boats,, hell your still wet behind the ears!!!! and u learned about engines from a man that raced for 30 years,, how can u learn from a man that probably die before u was born!!!!! so how can that be, U and phil can calculate this and that and all the figures u wont to,but the gps will tell the truth and is going to tell me what i wont to know, i dont care how much prop slippage i have or will have,and i dont need know one to explain nothin to me eitheir,, so take your pen and paper theory else where.

[zul8tr]

What do suppose we did before gps? I tested huge, kept good notes and received real good set up and driving info from a lot of top runners: Harry Pinner, Marshall Eldridge Jr, Mark Hauptner and others. Used water pickup speedo in combination with a measured distance and a stop watch (IMO beats gps cause relative to the water), then a course on a small isolated lake in West Palm Beach with a stop watch to do the lap and a fair amount of theory mixed in there (hard to prevent that since my field includes hydro and aerodynamics).

Prop design was discussed alot with Harry who made all of mine, then tested the poop out of them and found what worked on the race course.

Harry would say "it's not how fast your boat is , it's how fast it goes around a race course and finishes".

I this thread close to the end?

[champ20B]

Your only in your 30s and u have dedicated years to speed to boats,, hell your still wet behind the ears!!!! and u learned about engines from a man that raced for 30 years,, how can u learn from a man that probably die before u was born!!!!! so how can that be, U and phil can calculate this and that and all the figures u wont to,but the gps will tell the truth and is going to tell me what i wont to know, i dont care how much prop slippage i have or will have,and i dont need know one to explain nothin to me eitheir,, so take your pen and paper theory else where.

Ok. here is your calculations! Mr.Renfro ( my mentor) was 13 when his parents got him into racing. He was born in 1914 as far as I know. I helped him in his outboard parts buisness fron age 16 (part time) till I was 31. If he were still alive, he would be 99 years old now. People do live to be older than that. I am "close" to 40 myself now and thats all I'm gonna say about that. Also, I grew up in the powerboat manufacturing INDUSTRY. Although I'm not taking part in it anymore as to persue other interests, I'm no newcomer in any of this stuff. I'm just trying to help people out with thier questions from time to time here if that is o.k with everybody. I enjoy doing things like that once in a while, thats all. I wasn't trying to be mean and cut anyone down here.

[HankFrazier]

Ok. here is your calculations! Mr.Renfro ( my mentor) was 13 when his parents got him into racing. He was born in 1914 as far as I know. I helped him in his outboard parts buisness fron age 16 (part time) till I was 31. If he were still alive, he would be 99 years old now. People do live to be older than that. I am "close" to 40 myself now and thats all I'm gonna say about that. Also, I grew up in the powerboat manufacturing INDUSTRY. Although I'm not taking part in it anymore as to persue other interests, I'm no newcomer in any of this stuff. I'm just trying to help people out with thier questions from time to time here if that is o.k with everybody. I enjoy doing things like that once in a while, thats all. I wasn't trying to be mean and cut anyone down here.

tO BE HONEST WITH YOU I NEVER CARED WHAT MY TOP SPEED WAS AS LONG AS I WAS FIRST ON RACE DAY. I CANT SEE WHERE THE WAY YOU CAL. SPEED WOULD BE VERY HELPFUL TO SOMEONE THATS TRYING TO GO FASTER THEIR ARE TOO MANY OTHER FACTORS THAT COME IN TO PLAY.

[champ20B]

tO BE HONEST WITH YOU I NEVER CARED WHAT MY TOP SPEED WAS AS LONG AS I WAS FIRST ON RACE DAY. I CANT SEE WHERE THE WAY YOU CAL. SPEED WOULD BE VERY HELPFUL TO SOMEONE THATS TRYING TO GO FASTER THEIR ARE TOO MANY OTHER FACTORS THAT COME IN TO PLAY.

Well, it's America. Anyone is free to do what they want. Im just putting my two cents out for seekers who look at these forums, that are new to set ups on boats looking for advise. As for me, if I'm going to bust my chops building up a good racer, putting what little hard earned money I have into it, I'm going to know my rig in every context including performance in efficiency. There could be an extra few % that I might get that wont just run in the race, but actually set a record. When I get going eventually, I'll aim high while setting up my new "B" superstock runabout. These formulas help me see "OVERALL PERFORMANCE" not just one or two things here and there. If I think I can get a few extra % out of the whole package, it could be hull, engine, setup, or prop. But bieng that the prop is the link to motion, that is the key of where the FIGURING STARTS. Checking hull, trying set ups: ect, comes with it all. I'll say no more. I'm outta here!

[MWhite]

Mike you do agree with me, but of course you just cannot bare to admit I am right.

come on mike lets put it to the test, see who's so wrong shall we.
what is the very maximum revs, gear ratio and prop size you get with your engine at the highest speed you get ? don't tell me the speed, just the ratio, prop, and rpm's.

don't forget I can only tell you its maximum possible, not actual as you will be a bit slower , though probably not by much.!!!!!!!!

you and your friends will probably already know these figures to the very finest detail.

ok,, around 7300 7400,, 1.83gear with a 16pitch fishing prop for starts, this isn't my racing prop that I use, so we'll get to that later, u don't know the heights I run my motor,, wether my props is 2blade 3blade are 4blade the weight of the boat,and so on,your the guru,, u tell me,, give it your best shot, keep in mind I already know the answer and I got people that can backup what im saying.

[pdt]

max possible attainable with these figures would be 61.27 mph at 7400 rpm. with a 1.83 to 1 gear ratio.

if the speed obtained is over 61.27 then the figures given are wrong, as this is maximum possible efficiency.
to get higher speed at those rpm's with this gear ratio would need larger pitch than 16 inch.

.

[MWhite]

max possible attainable with these figures would be 68.91 mph at 7400 rpm.

if the speed obtained is over 68.91 then the figures given are wrong, as this is maximum possible efficiency.
to get higher speed at those rpm's with this gear ratio would need larger pitch than 16 inch.

.

Ok now do the same thing with a 20pitch mercury racing cleaver just like the one in my picture at 7200 rpms.

[pdt]

20 pitch at 7400 rpm and 1.83 gear ratio would be max possible of 77mph

by the way I did have to correct the first speed.