Musical Notes Equal RPMs -- Really!

[CATransplant]

No tach? Do you need to know what RPMs you're turning at WOT or idle? There's a way, but you have to be a little musical. You'll need any electronic keyboard, or an electronic tuner, if you have one. Here's a chart that shows RPMs by the basic musical sound your outboard makes while running. This chart works with any engine, since the number of cylinders only changes the pitch in multiples, so you can still hear the underlying note. Each note applies to several RPMs, which are octave multiples.

This takes a little getting used to, but try it out. It really does work!

Note -- RPMs (in four Octaves)

C# --520/1039/2078/4157
D -- 550/1100/2200/4400
Eb -- 583/1167/2334/4668
E -- 618/1236/2472/4944
F -- 654/1309/2619/5238
F# -- 693/1387/2775/5550
G -- 735/1470/2940/5880
G# -- 779/1557/3116/6232
A -- 825/1650/3300/6600
Bb -- 875/1750/3500/7000
B -- 925/1851/3702/7404
C -- 975/1950/3900/7800

 

[tashasdaddy]

Re: Musical Notes Equal RPMs -- Really!

play it again, Sam.

 

[jay_merrill]

Re: Musical Notes Equal RPMs -- Really!

So, um, if you have three boats running next to each other at the same speed but at different rpm, does that constitute a chord?

 

[Vlad D Impeller]

Re: Musical Notes Equal RPMs -- Really!

Can it make the fish dance?
Perhaps a certain note will make the fish jump into yer boat.

 

[CATransplant]

Re: Musical Notes Equal RPMs -- Really!

Very funny, you guys. Still, it works. I'm just sayin...

 

[jay_merrill]

Re: Musical Notes Equal RPMs -- Really!

Vlad, that would be the aquatic musical, Fish Dance, starring Jennifer Seals and Michael Nourifin!

 

[F_R]

Re: Musical Notes Equal RPMs -- Really!

All joking aside, it makes sense. In the old days we used a tachometer that vibrated reeds according to the frequency of the vibrations. And all the harmonics too. Took some getting used to. As for musical notes. I am a world class dummy, have no idea what all those notes are.

 

[CATransplant]

Re: Musical Notes Equal RPMs -- Really!

All joking aside, it makes sense. In the old days we used a tachometer that vibrated reeds according to the frequency of the vibrations. And all the harmonics too. Took some getting used to. As for musical notes. I am a world class dummy, have no idea what all those notes are.

That's why I said you have to be a bit musical to use this. I have an electronic tuner, since I play a few instruments. It's kind of fun to determine the WOT RPMs using it. I don't want to hook up a tiny tach to my 6hp Johnson, but I know that it's running between E and F, so it's doing just fine.

You're right about those vibratory tachometers. I actually think you can still buy them, but they take a little getting used to. I used to use one on my racing motorcycles. Cool beans!

 

[drewmitch44]

Re: Musical Notes Equal RPMs -- Really!

i play drums so i got a tach!

 

[tashasdaddy]

Re: Musical Notes Equal RPMs -- Really!

i got kicked out of music class. teacher told Mom she was wasting her money. Yes, i agree it will work.

 

[NSBCraig]

Re: Musical Notes Equal RPMs -- Really!

i play drums so i got a tach!

 

[Bigprairie1]

Re: Musical Notes Equal RPMs -- Really!

I fully agree with this musical note thing. Its one of the reasons I don't like the stereo too loud at all in the boat when its moving. Basically its unlikely whatever is playing on it is in tune with the boat rpm and it ends up sounding all like an off-key song while underway and its very annoying and distracting. Anyone else experienced 'stereo shut down' when heading out?
BP

 

[jay_merrill]

Re: Musical Notes Equal RPMs -- Really!

I don't play music while out in the boat for the same reason that I don't care about having a "go-fast" boat - pretty hard to "commune with nature" at 50 mph, with James Brown screaming "hit me !!!!!" at 102 dBa!

(Can I hear some horns so I can do that "wiggle foot dance" that he used to do?)



PS: After this thread, I might have to start playing guitar again! Maybe I'll go buy a Martin acoustic and mount a Tiny Tach on the headstock! Since I like my acoustics with a piezo pickup under the saddle, I could just wire it up to that! And Monte Montgomery thinks he has his "axe" wired up ... he'll have nuthin on me, I tell you!

 

[CATransplant]

Re: Musical Notes Equal RPMs -- Really!

Back when I was 16 (sometime in the dark ages, I think), not long after I got my driver's license, my family went on a long vacation trip. I was so proud when my father let me drive for awhile during the trip.

After about half an hour, he said, "Son, your speed is varying by about 15 miles an hour while you drive. You're doing a good job watching the road, but you need to keep a constant speed."

Well, I couldn't figure out how to watch the road and the mirrors and the speedometer at the same time, and told him that. "It's easy," he said. "You play the clarinet. The car is making a musical sound as you drive. Just play the same note all the time and you'll be driving the same speed." Bingo...the light went on in my head, and I had no problems after that.

Now, kids have cruise control, so they don't have to learn this stuff, but it sure worked well at the time.

Then there was the time he taught me to drive his 1948 Dodge pickup with a non-synchromesh transmission. "Don't grind the darned gears! Transmissions are expensive to fix!" Then he taught me the whole double-clutching and matching engine speed to transmission speed routine. Kids certainly don't have to learn that these days.

 

[JB]

Re: Musical Notes Equal RPMs -- Really!

Well, yes, it works, but why bother?

For years I shifted gears by ear and cruised at fairly constant speed by ear.

With so many distracting sounds (including bad music systems blasting bad music) and very quiet engines in cars and boats I find tachometers and cruise control very nice and worth the modest cost.

 

[jay_merrill]

Re: Musical Notes Equal RPMs -- Really!

So, there is a guy in another thread who wants to know what pitch prop to run on a 25hp Yammy/14' Trihull combination .... should I tell him to go get and electronic guitar tuner and check to see what note the motor is running at when at WOT?

 

[CATransplant]

Re: Musical Notes Equal RPMs -- Really!

See Below

 

[CATransplant]

Re: Musical Notes Equal RPMs -- Really!

So, there is a guy in another thread who wants to know what pitch prop to run on a 25hp Yammy/14' Trihull combination .... should I tell him to go get and electronic guitar tuner and check to see what note the motor is running at when at WOT?

Why not? Tuners are cheap. But, if his kid has a toy electronic keyboard, that'll work, too. You just match notes. I'm not saying it's a substitute for a tach, but folks with smaller outboards that don't have tach connections and who don't want to wait for a Tiny Tach they ordered can use this system.

BTW, my next door neighbor's new Toro lawnmower is running at A (3300 RPM) as I'm writing this. It's slightly flat, though, so it's probably closer to 3200.

 

[fishmen111]

Re: Musical Notes Equal RPMs -- Really!

Thank goodness I got the Yamaha keyboard option with mine. I'm going to change the prop and see if I can get her up to "G" from "F#".