Even more prop testing

[warthog5]

It's funny... the Admiral came down to the marina to help me swap out the Rev 4 for the Mirage, and she is asking me... "Why does that one have 3-blades, and that one 4?" "Aren't 4-blades better?" "Gee... that one sure has a nice shine!" "Why is that one painted black?"

Sound's like my ex, when I asked why she bought the car she had.

"I like the radio"

 

[warthog5]

On any new prop it really need's to be computer checked.

What's stamped on it is NOT nessessairly what it is.

Example:

I tokk my 2- Suzuki 3 X 14 X 18's to the prop shop to have them checked so I could get a baseline.

One of them had 16.5 pitch in it. The other had 17in pitch in it.

This is more common than you think.

 

[Megabyte]

On any new prop it really need's to be computer checked.
What's stamped on it is NOT nessessairly what it is.

Absolutely true!

Once I find a prop that is close to what I want, I'll ship it to Wildcat Propellers in Chesapeake, VA to have it tweaked and trued...

http://www.wildcatprops.com/

I've already see what they can do with a pair of big inboard wheels (one of which that had impacted with a submerged log).
The damaged prop was way out of spec, but so was the "factory fresh" prop that had not been damaged. :shock:

After repair, and tweeking to take out about an inch of pitch, the diesels were spot on the money at WOT and the whole rotating assembly was silky smooth.

Made me a believer in 'Prop Scan'. :wink:

 

[Porkchunker]

So Kevin...you going to keep that 4-blade prop on the Megabyte? It sure looks like it performs well at mid-range cruise.

 

[Megabyte]

Have not decided yet Dave.

I have a Mirage 3-blade on the boat right now that I need to get some numbers off of before comparing the stats between the 3 props.

Once I have the data, I'll decide my next move.
If that Rev 4 was just a 15x15 or a 15x16...

 

[Porkchunker]

So...if it is a bit off, can't you "send it to Wildcat Propellers in Chesapeake, VA to have it tweaked?"

 

[cbigma]

Have not decided yet Dave.
Once I have the data, I'll decide my next move.

Make that -our- next move, Kevin

Wow, if there ever was a prime example of why all Parker owners who spend any amount of time on the web owe it to themselves to hang out at ClassicParker.com at least once a week...here it is.....

I have almost the same rig as Kevin... except maybe not the extra bazillion gallons of fuel he hoards under his deck. :wink: Same model hull, same OX66 power, close to same year etc. I carry extra gear all the time for diving, so I figure his extra fuel = my extra gear weight.

I need to replace my prop. He does all the hard work changing out the props, making the runs, recording and posting the data, getting quizzed by the Admiral, etc. I sit back and check his progress each night and wait for the results.

He does the analysis,, declares a winner,, and I go out and get the same prop. Sheesh.... Slam dunk. Like hitting the Staples "That was easy" button.

So I guess the trick is...... when you decide you need to make an improvement on your Parker,,, find somone on ClassicParker.com that has your exact same model and power,,,, then give them subtle hints about how much more efficient their rig would be if only they would make that certain improvement! :roll:

Thanks Kevin. :mrgreen:

I'm looking forward to the next installment......(Could 'ya step up the pace a bit,,, I need to re-prop by June! ) 8)

.....John

 

[DaleH]

What's stamped on it is NOT nessessairly what it is.

Example: I tokk my 2- Suzuki 3 X 14 X 18's to the prop shop to have them checked so I could get a baseline. One of them had 16.5 pitch in it. The other had 17in pitch in it.

This is more common than you think.

Wart ... that is very common on Suzi props, to where Dunk advises subtracting an inch or two of their labeled pitch to determine what is actually is. I can't I've observed this anomaly to such a degree with other brands.

 

[B-Faithful]

So I guess the trick is...... when you decide you need to make an improvement on your Parker,,, find somone on ClassicParker.com that has your exact same model and power,,,, then give them subtle hints about how much more efficient their rig would be if only they would make that certain improvement! :roll:

Just make sure that guy has a friend who has spent wayyyyy too much money on prop testing himself and has 4 spares laying around...

 

[cbigma]

Just make sure that guy has a friend who has spent wayyyyy too much money on prop testing himself and has 4 spares laying around...

And because you guys have posted your results on ClassicParker and shared them with the Parker community there are hundreds of us out here who benefit from your hard work and generousity.

Such is the sprirt of ClassicParker

Thanks

......John

 

[Megabyte]

For those following the saga of my prop testing, here is the latest installment...
This prop is a 14.5x17 SS Merc Mirage 3-blade.
(maybe B-Faithful can verify that size for me)

On the way out into the Bay at sunup to fish a local tourney, the water was flat and I saw 31.0 kts @ 5000 rpm on this Mirage, but because of limited visability and crab-pot floats, I was unable to get the fuel burn or the actual WOT rpm while attempting to drive defensively. :shock:

Just as the wind was getting up around noon, I pulled our lines and made a dash up the Bay recording these numbers in a 1'+ Bay chop. Water temp was aprox 64 degrees.

RPM, Speed in kts, fuel burn in gph.

700, 3.2 kts, 1.6 gph
3400, 10.4 kts, 10 gph
3600, 12.0 kts, 11 gph
3800, 14.5 kts, 12.6 gph
4000, 19.0 kts, 13.0 gph
4200, 23.0 kts, 13.5 gph
4400, 26.5 kts, 15.0 gph

The prop feels really good, but I have not done any kind of slip calculations on any of the prop data so far. From the "seat of the pants", this wheel felt pretty responsive. Still, it was just a little too rough to get numbers above 4400 rpm.

I can tell you that it was tough getting my speed down low enough to troll for rock. 700 rpm is the absolute low end when trying to keep a big block Yammie cool, and even with the trim planes fully deployed, I was running between 3 and 3.2 kts much of the day.

For the folks comparing figures, here are the results of the first two tests from my previous posts:

-------------------------

Just dug out my performance notes from last year after installing the 15x17 AL Solas prop.
Water temp 54 degrees, 1' Bay chop, 17 Apr 05.

RPM, Speed in kts, and fuel burn

800, 3.5 kts
1000, 4.3 kts, 2.2 gph
1500, 6.0 kts, 3.4 gph
3200, 10.6 kts, 10.3 gph (on plane)
3600, 15.5 kts, 10.7 gph
3800, 18.2 kts, 11.6 gph
4000, 20.0 kts, 12.4 gph
4200, 22.4 kts, 14.5 gph
4400, 24.4 kts, 15.2 gph
4600, 26.3 kts, 16.8 gph
4800, 27.2 kts, 18.8 gph
5000, 29.0 kts, 22.0 gph

---------------------------------------

Compare those figures with the 14 5/8 x 15 Revolution 4
Water temp 53 degrees, 1' Bay chop, 15 Apr 06.

RPM, Speed in kts, and fuel burn

800, 3.6 kts. 1.7 gph
4000, 19 kts, 10.3 gph
4100, 20.5 kts, 10.9 gph
4200, 21.0 kts, 11.2 gph
4300, 22.5 kts, 11.6 gph
4500, 23.6 kts, 12.2 gph
4600, 24.7 kts, 13.1 gph
4800, 25.5 kts, 15.6 gph
5600, 30.5 kts, 26.1 gph
5700, 30.8 kts, 26.2 gph

Now that I've found my notes, it appears that the Rev 4 is a lot more efficient than I thought!

 

[B-Faithful]

kevin, I think the mirage plus is a larger diameter prop. I think they are 15.25x17. not possitive though. As you know it is a loaner from a fellow tht'er

Here is a link to the Mirage Plus:
http://sites.mercurymarine.com/portal/p ... ema=PORTAL

 

[DaleH]

I can tell you that it was tough getting my speed down low enough to troll for rock. 700 rpm is the absolute low end ... running between 3 and 3.2 kts much of the day.

Kev:

You ought to troll a drift sock or a 5-gallon bucket off of each side of the boat, amidships can work too.