Whaler Central - Boston Whaler Boat Information and Photos

Posted by ahandiman1 on 04/04/12 - 1:03 PM

Hi All,
I'm new to the forum so bear with me and feel free to point out anything I'm missing.

I recently purchased a 1973 13' classic Boston Whaler with a 2000 Honda 40 HP BF40A LRT motor. On the test spin with the owner it seemed pretty good overall...the price was right so I bought it.

Now that I've been out with it a few times I wanted to get your opinion on propeller. I would like a propeller that is good for going faster once on plane, I'm not as concerned with getting on plane fast or staying on plane at lower speeds.

The current prop only has these identifying marks.. 2 1/4 x9-6, which is complete garbage. It's not a Honda Prop and the Honda dealer said there are only three props to choose:

Propeller Dimension
B D P R Honda Part Number
3 11 15 R 59130-ZV5-015AH
3 11 16 R 59130-ZV5-016AH
3 11 17 R 59130-ZV5-017AH

He said I would have to choose pitch. I think the 17 would be best, but having never owned a Honda mated with a Boston Whaler thought maybe someone here has better insight or could recommend a different brand if there's one better than the Honda stock. (the listed props are aluminum..I'd like to stick to aluminum as I'll be taking this into some back water areas of the Mississippi in MN and will definitiely ding it up a few times ..at least.)

Edited by ahandiman1 on 04/04/12 - 1:35 PM

Posted by Joe Kriz on 04/04/12 - 1:50 PM

He is correct about only being able to choose pitch...

Many people think we can choose the diameter... That is not correct.
The engineers figure out the diameter for the pitch props they sell for the particular model and size of engine...

13 pitch
15 pitch
17 pitch
etc......

To be completely accurate in choosing the correct brand and pitch of prop, you really need a tachometer onboard...

The proper pitch propellor should have the engine run between the recommended WOT (Wide Open Throttle) RPM's. In this case, look in your Honda book and see what the recommended WOT is for your motor...
That is where you want to be with any prop you choose...

Maybe others here with the same boat/motor combination can tell you what prop they use.

Posted by Tom W Clark on 04/04/12 - 1:52 PM

Welcome to Whaler Central.

There are many, many more than just three propeller choices for that motor.

To answer your question we need the following information to get started:

- What is the recommended WOT engine speed range of this motor?

- What is the gear ratio of this motor?

- How fast does the boat go now?

- At what engine speed (RPM) is that top speed achieved?

Posted by Tom W Clark on 04/04/12 - 2:17 PM

I did some research for you. The 2000 Honda BF40 has a 5000-6000 RPM WOT range and a 2.08:1 gear ratio.

The Honda Propeller catalog shows 31 different propellers to fit the BF40, and that is just Honda. There are dozens of aftermarket props to fit your motor too. I don't know what the hell your dealer is talking about and I suspect he doesn't either.

The propeller you have now is almost certainly a Solas 12-1/4" x 9" three blade aluminum propeller.

If your Sport 13 is good for 36 MPH with its 40 HP motor you will probably want a 14" pitch version of that prop. If you want to step up to a stainless steel propeller, which I highly recommend, then you might consider the 10-1/2" x 13" Honda Turbo three blade, part # 58110-ZV5-E20. This propeller is made by Precision Propeller Industries, inc. (PPI) and is also sold as the Turbo Hot Shot and the Stiletto Triad 3.5.

Honda does not manufacture any of their own propellers. They offer props made by PPI, PowerTech, Solas and even one from Mercury!

Posted by ahandiman1 on 04/04/12 - 2:44 PM

Thanks Joe and Tom
It sounds like I'll need to get a tach installed to figure out RPM's and bring along a GPS receiver to figure out speed and gauge the best Prop on what I discover there.

To answer your question we need the following information to get started:

- What is the recommended WOT engine speed range of this motor? The WOT range is 5-6,000 rpm.

- What is the gear ratio of this motor? 2.08:1 according to the service manual.

- How fast does the boat go now? unknown..unknown rpm. no way it was approaching 36mph though.

- At what engine speed (RPM) is that top speed achieved? unknown

Just saw your last post Tom, I'll see if I can find a 12-1/4x14" Solas online. The dealer didn't impress me with knowledge.. of course he wanted me to bring the boat in to gauge if it was properly setup vs. what I had which was just the propeller and engine info.

Thanks for the help!

Posted by Joe Kriz on 04/04/12 - 4:06 PM

Just saw your last post Tom, I'll see if I can find a 12-1/4x14" Solas online.

Just for clarification, I did not see Tom say 12-1/4 diameter.... for that 14 pitch prop recommendation...
Again, the engineers figure out the diameter for the pitch prop for a certain motor....

Here is what Tom said:

If your Sport 13 is good for 36 MPH with its 40 HP motor you will probably want a 14" pitch version of that prop.

The diameter is what it is and we have no choice of diameter when buying a certain brand and pitch of prop...

Here is a general test of one of my prior boats.

15 pitch prop gave a better hole shot but less top end speed.
17 pitch prop was slower out of the hole but had a couple of miles an hour faster at top end.

The WOT RPM was within the manufacturers recommendations.......
The above props were the same manufacturer but different pitches....

I used the 15 pitch for waterskiing and general use, and the 17 pitch when I felt like using it...
Whichever one I wasn't using was kept in the truck as a spare if I was on vacation or overnight adventures.

Posted by Tom W Clark on 04/04/12 - 6:10 PM

The "Solas Honda" is the basic Honda aluminum three blade.

The 12-1/4" x 9" version is part # 59130-ZV5-009AH. I suspect what you read off the pro is 2-1/4x9-R for Right Hand Rotation. There is no way a Sport 13 will have much speed so under propped.

The 11-1/8" x 14" version is part # 59130-ZV5-014AH.

If you want top speed, skip the cheap Taiwanese made Solas aluminum and buy a nice domestically made stainless steel model.

Posted by Patrick199 on 04/04/12 - 7:51 PM

I have a 1981 13' with a Honda bf40 on the back.
When I first got the boat it had a prop with a 13" pitch and it was not enough. I think it spun about 5800 rpm at wot and top speed was only about 30 mph on a good day. I don't recall the diameter.
When I put the 14" pitch prop on it the rpms only go to about 5600 and top speed is 34 - 35 mph. Cruises nicely at about 5000 rpm and 31-32 mph.
I think it can probably turn a 15" prop and I plan to pick one up pretty soon. I'm guessing the rpm would drop to 5300 and top speed might be 37-38 mph.

Posted by ahandiman1 on 04/12/12 - 11:09 AM

#10

Thanks for all your help guys. Got a tach setup and ran with the current prop..easily went up to 6000rpm, got onto plane around 5500rpm, which obviously isn't good.

Based on the comments here I punted a guess that a 11x15 would at least get me in the range where I could figure out if that was the right prop or which way to go from there.

WOW! the boat is on plane a lot quicker and gains speed all the way to 5300 rpm. It may have more in it, but I haven't borrowed my buddies GPS to figure out how fast the boat was going. I could feel it gain and lose speed as I adjust the trim, but without a gps it's hard to know how much that's truly affecting anything.

Thanks for the help!