MacGregorSailors.com

I have scoured the threads about them....narrowed it down to wanting the 4 blade prop since we, like others, spend most of our time at cruising around 6 knots

On amazon I found these two OEM Honda 4 blades

Math is NOT, and I mean seriously, NOT my strong suit

Whats the difference between 4X11-3/8X10 and 4X11-7/8X9

Seriously the way my brain works is the numbers are different...I suffer from Dyscalculia so I try to avoid numbers

Is one better than the other? The Fractions at the end of the prop number are different....but both 4x11... No idea what the fractions mean (don't try, I've looked it up...the disability makes it impossible to understand what they are talking about with pitch and things.....understand the concept, not the numbers. I learned to live with it)

I want to order this today...our OEM 3 blade is toast. We sail our boat some, but do spend a majority of time cruising....top speed very rarely but we do WOT occasionally. I also don't want to order the wrong one will put strain on the engine/lower unit (read here wrong prop can do that)


Appreciate any thoughts or help

Cheers
Dave

We

81venture wrote:Seriously the way my brain works is the numbers are different...I suffer from Dyscalculia so I try to avoid numbers.

Wow. That's unusual, and something I can't even remotely relate to, as I'm an engineer, and I actually think better using numbers, or numerical concepts. The touchy-feely stuff totally eludes me. Poetry/art/literature? Human interaction? Alien language. And forget arguing with the admiral; that's one in the loss column, even before it starts. But oddly, music is, well, music to my ears. Probably because it's mathematical at its root.

As to the prop, do you have links to the Amazon offerings?

I use a 4-blade Solas. The original prop that came with my boat, and its spare twin, were Honda 3-blade offerings, but I believe they were originally made by Solas, too.

The 3-blade is 11.75" diameter by 10" pitch.

The 4-blade is 11.80" diameter by 9" pitch.

The difference in size is negligible. The difference in pitch and number of blades is significant.

More blades means lower pitch number (by 1) for the same performance, more or less. Larger diameter is better for low-speed operation and high thrust. But there are limits to what you can do, since you can't put a giant prop on there (it won't physically fit), and you can't change the speed of the prop shaft (the gearing and max engine speeds are fixed by design).

I use the 4-blade for pulling a wakeboard. It has the annoying habit of generating a loud howl between 2000 and 2500 rpm, or somewhere around there. Right where I like to run the engine on the Erie Canal. Faster is OK, as the sound goes away. But I don't think I'd recommend that prop for the BF50 for that reason. I went back to using the original 3-blade for the canal. I thought maybe I had a lower unit problem, but others with that prop report the same sound, and it's not present with the 3-blade.

So if you're looking for a 4-blade, I'd suggest something other than the Solas. Which may also be the Honda prop. Which is why I asked if you could post a link to it/them.

Ha! It is a most unusual disability indeed....I am above average intelligence, understand mathmatical CONCEPT, and engineering, Speak/read/write Korean and a lot of spanish...I pick up languages quick. I am not creative either, can't draw, hate poetry

however, Although I may know WHAT is being asked in a mathematical formula, forget about doing the "figures" to get the answer....calculator makes it worse, get confused, see numbers wrong... I can't read read phone numbers well unless they are spaced apart...so 5551234567 is very hard to interpret however 555-123-4567 is easier....It also comes with Dysgraphia, which is the inability to see Spatially, like say a plan calls for 8x10x14 and another is 8x11x10....I can not "see" the difference in the shape from the numbers....I know only is a rectangle in this case Forget fractions!!

Like I said I learned to live with it....

here's the links

http://www.amazon.com/Honda-58134-ZV5-0 ... B00AJTNWR0

or

http://www.amazon.com/Honda-58134-ZV5-0 ... B00AJTNVJO


thanks

dave

I just posted this on another thread but here's a good calculator for determining prop size and other information.

Keep in mind it's only for displacement speeds, not for planing information.

http://www.vicprop.com/displacement_size.php

81venture wrote:. . . forget about doing the "figures" to get the answer....calculator makes it worse, get confused, see numbers wrong...

Then I guess my Hewlett Packard calculators aren't for you. They use Reverse Polish Notation (RPN), and to add numbers, like 2 plus 3 (for instance), you'd input "2_enter_3_plus". Instead of parentheses, like (2+3) x (4+5), you'd input "2_enter_3_plus_4_enter_5_plus_multiply". And there's no 'clear' or 'clear entry' button. Folks never ask to borrow one of mine more than once.

As to the prop, the one in the second link appears to be the Solas I was talking about. Every close-up detail matches exactly, including the blade shape, rubber spline cushion, hub details, even the ring in the inside of the exhaust hub. It may say Honda on it, but I'd bet it's made by Solas.

It's a good prop, with good thrust at lower speeds, and much better in reverse than the 3-blade. But it probably makes that howl at a certain engine speed range. If that's not a concern, then go for it.

If you're never going to go fast with this prop, perhaps a steeper pitch, like 10" or even 11", for low speed cruising at lower engine speed, to extend the fuel range by running the engine slower. Hull speed only requires something like 7-8 hp on an , so over-propping it won't be detrimental to the engine if you don't try to run at full throttle. If I was going to take a long cruise on the Erie Canal, running just below hull speed (there are speed limits on most of it, and lots of no-wake zones), I'd sniff around for something to intentionally over-prop it. But I'm not sure that's what you want to do here.

Edit: While sniffing around, I came across Honda's prop web page, and they list "Solas Honda" props. So now I'm sure that's the same Solas prop I have.

xx

Tomfoolery wrote:

81venture wrote:Seriously the way my brain works is the numbers are different...I suffer from Dyscalculia so I try to avoid numbers.

The 3-blade is 11.75" diameter by 10" pitch.

The 4-blade is 11.80" diameter by 9" pitch.

The difference in size is negligible. The difference in pitch and number of blades is significant.
.

Slight correction, although not a big deal:

Both props listed are 4 blade. One is 11.375" diameter the other is 11.875".

I have a Honda BF50A and am in the market for a prop. The board members here are knowledgeable, and helpful, but don't negate your responsibility to have a reasonable understanding of propellers which you might purchase. Here is a site I found very helpful. It really simplifies the mistery of the beast.

http://www.formulapropeller.com/propellers.html

You may also want to see this site
http://marine.honda.com/parts/accessori ... propellers

Ray

budgates wrote:

Tomfoolery wrote:

81venture wrote:Seriously the way my brain works is the numbers are different...I suffer from Dyscalculia so I try to avoid numbers.

The 3-blade is 11.75" diameter by 10" pitch.

The 4-blade is 11.80" diameter by 9" pitch.

The difference in size is negligible. The difference in pitch and number of blades is significant.
.

Slight correction, although not a big deal:

Both props listed are 4 blade. One is 11.375" diameter the other is 11.875".

I was referring to the two props I have for my boat, not the ones in the Amazon links.

Try to look at it this way. The props you listed are:
4 X 11-3/8 X 10
4 X 11-7/8 X 9
-The 4 in both cases is the number of blades
-11-3/8 & 11-7/8 is the diameter. If it helps to get rid of the fraction, use 11.375 & 11.875. 11.4 & 11.9 are close enough if you want to round off the extra.
-10 & 9 are the pitches. As I understand it, this is the angle of the blades.

I'm an engineer also, but I got my master's degree in business and generally spend my days translating engineer into english.

Jeff

marine.honda.com has a prop calculator. For the 4 blade it says get the 58134-2V5-010AH but be aware that these 4 blades hum between 2000 and 2500 rpm. The 4 blade hums on my suzuki 50 at these rpms. For the 3 blade prop it calls for 59130-ZU5-011AH. On my suzuki 50 I get about 4 mph more with the 3 blade at WOT. The hum on the 4 blade bothers me so I put it in the shed and now only use the 3 blade.

C Buchs wrote:Try to look at it this way. The props you listed are:
4 X 11-3/8 X 10
4 X 11-7/8 X 9
-The 4 in both cases is the number of blades
-11-3/8 & 11-7/8 is the diameter. If it helps to get rid of the fraction, use 11.375 & 11.875. 11.4 & 11.9 are close enough if you want to round off the extra.
-10 & 9 are the pitches. As I understand it, this is the angle of the blades.

I'm an engineer also, but I got my master's degree in business and generally spend my days translating engineer into english.

Jeff

Although I really appreciate all your help....you have to understand I can't do the NUMBERS....jeff your simple explanation makes perfect sense, and Nice Aft I have a very good understanding of how props work, I know what pitch and diameter are as well...However just trying to read jeffs post makes no sense to me...there are to many numbers together, mixed with fractions to boot. That part of my brain just gets overwhelmed and shuts down, like trying to read chinese for the first time and expected to do so onstage in front of a crowd of millions...no pressure right? That's just what happens when I get further than 2+2=4. It's not just an inability to do math, but an inability to even see the #'s and be sure I am not transposing, flipping, or adding extras.....it's just a big jumble.

The concept, and the explanation of pitch and everything make perfect sense. that's theory and I grasp that well.

I know it is difficult to understand...Dyscalculia is very similair to Dyslexia. But I have no issues with language or letters, and I play music well but cannot read a note of it as Dyscalculia affects that as well.....

Anyway I digress

My problem looking at the two props and the fractions is I do not know which is bigger, better, or too much. I would order the 2nd one as suggested, but the possibility of weird noise has me leary.

I would like to be able to do top speed on occasion (top speed is a relative term) 15-17mph is plenty every now and again. Doubt we would ever pull a skier or wake boat...yes would most likely cruise about 6-8

My problem is understanding the concept is one thing, but using the numbers to arrive at the right conclusion is what stops me....so I asked for help here, like I always do for any problem where my disability hinders me.

I do appreciate the help trying to "simplify" the math, but I tell ya it does no good for me....Again I know it is difficult to understand, and the hull I endured as a brilliant child that couldn't add or do math. "He isn't trying hard enough, etc" was horrible growing up....I Was diagnosed in my adult years, but graduated with about a 7th grade "math level" and advanced everything else.....oh, and I can't measure with a tape for sh~t either, and don't ever have me build something for you out of plans and wood But give me a machine and I take em apart and back together again with ease

I am not sure if a 4 blade is better or not...All I know is the OEM 3 blade is raggedy as hull and needs to be replaced. Normally I would pull it off, read the pitch and order the same. However this boat is bigger, and different props for different uses I am finding. The one on it worked good enough, it went about 14 according to the Garmin, but I suspected the ragged bent blades were def an issue lol.... I know we like to motor a lot at the local lake where sailing is non-existent, I like to be able to plane once in a while and achieve at least 15 without straining the motor... Fuel economy is not a huge concern, we day sail/motor, and occasionally overnight. It has 2 6 gal tanks I filled, and we have been out 4 times and there is still plenty of gas in them (except I have a habit of draining some out for the lawnmower vs driving and going to go fill the little can)

I want to cruise, top speed sometimes, but most importantly not strain the motor....Usually 2-4 people and a small dog, and day gear (beer cooler, snacks)....overnight is just M and I and small dog.

whew, sorry for the book

dave

ris wrote:marine.honda.com has a prop calculator. For the 4 blade it says get the 58134-2V5-010AH but be aware that these 4 blades hum between 2000 and 2500 rpm. The 4 blade hums on my suzuki 50 at these rpms. For the 3 blade prop it calls for 59130-ZU5-011AH. On my suzuki 50 I get about 4 mph more with the 3 blade at WOT. The hum on the 4 blade bothers me so I put it in the shed and now only use the 3 blade.

Then I may just replace the 3 blade with another 3...but once again there are all kinds of choices with numbers

oy vey

81venture wrote:Then I may just replace the 3 blade with another 3...but once again there are all kinds of choices with numbers.

Then my recommendation would be to use the same prop mine came with - 11.75 diameter, 10" pitch, 3 blades. Honda part number 58130-ZV5-860ZA. I get 16 mph at 5700 rpm or so, which is close to the max engine speed, with no ballast, 3 adults aboard, and the mast up. I haven't tried other 3-blade props, so all I can say is that mine does what I said it does, on my boat.

The one on the right is my spare, which was repaired at some point. My daily driver looks the same, but with nice paint and no repaired spots.

The one on the left is the Solas Amita 4-blade I was talking about. The one that sings at slow cruise speeds.

I like mine - it's got three blades and the blades are HUGE! I think three HUGE blades is better than 4 little blades at low speed maneuvering if your into that kind of thing. For me it just means I need to be very careful with the throttle because if I push on the throttle too hard everyone in the boat falls over. I think the 4 blade jobs with smaller blades make the boat go faster, right?

Not sure about this stuff.. motors, props, dangerous noisy spinning stinky things, if I was really into that kind of thing I would have bought a Bayliner and spent all my time at the dock doing engine repairs like all those guys who own them. What's the deal? You put up the sail and the boat moves forward - it's as easy as that. Why make it worse.