Even more prop testing

[Megabyte]

Last year I did a bunch of prop testing, looking for the perfect prop.

I tested 3-blade and I tested 4-blade, but after getting a major headache, I settled on a 3-blade AL Solas prop in 15x17, show here a little 'polished' by a sandbar near Gibson Island.

The Solas was a good all-around prop, but I could only turn 5000 rpm out of my 225 Yamaha OX66 (33 kts on flat water), so I was in search of about 500 rpm while retaining good mid-range bite.

This year, with the help of B-Faithful, I'm testing props once again.
(am I nuts or what?)
My neighbor and I put the prop on, then took her for a test...

This prop is a Mercury Revolution 4 that is a 14 5/8 x 15
Quite a size difference from the Solas, but I was interested in seeing what the 4-blade would do.

Here are the stats that we saw on it this evening...

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

The motor is rated for 5000 to 5500 rpm, so going to this size put me a little underpropped, though not by a lot.

I'm certainly not a prop guru. I'm just trying to find something to get me in the top of my motors range, even though the (in)famous Chesapeake chop keeps us much firther down in the motors range most of the time. With the Solas last season, it wasn't unusual for me to run in the 3500 rpm range when the Bay got bumped up.

My thought was that if I propped her a little under, on those days when the Bay gets lumped up, I won't be lugging the motor too bad.

Comments from the more 'prop literate'?
BTW - I still have a SS 3-blade 14.5 x 17 I believe... that I can try next.

 

[B-Faithful]

I think you may be underproped with the 15" Rev 4. Not sure though. As far as speed is concerned make sure you are not using any tabs and trim the engine all the way up until it either starts to ventilate or is porpoising then drop it down just a hair. Your fuel burn also has me thinking you are under proped. To be burning just 12gph at 4500rpms with a traditional EFI outboard at 4500 shows that your engine is either extremely efficient or you have a very low load on the engine.

post up some numbers when you have had a chance to trim her out. My bet is that the 17" 3 blade Mirage plus may give you better performance.

I think that 15" Rev 4 may work best with an XL, Deep V or 4 stroke engine powered Parker that is to turn up to 6000.

Keep us posted!

 

[Megabyte]

I agree Greg, If the wind lays down today, I may test that 3-blade Mirage.
Sitting side-by-side next to the Solas, the Mirage is noticably larger, which has me wondering if it will even turn up to 5000. The Mirage has a lot more blade area than the Solas...

 

[B-Faithful]

I have a merc black max 17 for you too.... :lol:

 

[DaleH]

I'd try those other props too ... your speed and burn numbers don't look too good with that 4-blade.

 

[warthog5]

4 blade's have been known to help holeshot and keep the motor hooked up in slop, but at the cost of top end speed.

Your result's may very.

 

[Megabyte]

I removed the 4-blade before reading your note Greg, but I did install the 3-blade Mirage this afternoon for further testing.
Could not give her a proper test as it was blowing 15 kts out of the north. I did putt around in the creek a bit and then did a little maint on my neighbors dock.

Bobby... the 4-blade did hook well and the motor spun up really nice... I also did some hard 90 degree turns @ 4500 rpm and not even a hint of blowout. That prop did hook up, she was probably just a bit too small. I'm thinking at a 15x15, or a 15x16 Rev 4 might just be a good choice...

Not going to worry about it though. I'll try the Mirage and see how she does first.
Just gotta wait for the wind to lay down...

 

[B-Faithful]

let me know if you want to pull my 17" Rev 4. Tonight I hit 41.7mph at 5330 w/ 70 gal of fuel, 4 kids, 3 adults and a cooler with dinner. I was cruising at 29.7mph burning 10.3gph at 4020rpm.

Like I said, My bet is that 15" rev 4 would be perfect for someone running a 4stroke that needs to be around 5700-6000.

 

[Megabyte]

I was cruising at 29.7mph burning 10.3gph at 4020rpm.

:shock: About... 8 kts more than me at the same rpm and fuel burn.
I was a little heavier carrying about 150 gallons of fuel and a full load of fishing gear, but still...

I hope to have numbers on the Mirage sometime this week.

 

[rangerdog]

I was cruising at 29.7mph burning 10.3gph at 4020rpm.

:shock: About... 8 kts more than me at the same rpm and fuel burn.
I was a little heavier carrying about 150 gallons of fuel and a full load of fishing gear, but still...

I hope to have numbers on the Mirage sometime this week.

Kevin, remember his hull only weighs 3600 pounds. No disrespect intended.

 

[B-Faithful]

Kevin, remember his hull only weighs 3600 pounds. No disrespect intended.

No disprespect taken. Truth is the truth. The hull weight of the 25 Maycrafts CC and pilot are around 3600# (doesnt included pilothouse--Just hull). It is quite a bit lighter than the Parker. I also only have 10 degrees of deadrise and an 8'6" beam which also helps the speed. The speeds I posted are in MPH too not in Knots as you have listed.

 

[Megabyte]

None taken!

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?"

Then she asks... "Why are you doing all this?" :?:
I told her... "Because I'm never satisfied and like to tinker with boats". :lol:
No response...

 

[Outta Here]

To be burning just 12gph at 4500rpms with a traditional EFI outboard at 4500 shows that your engine is either extremely efficient

"estremely efficient"......It's a Yamaha! :lol:

 

[Megabyte]

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!

Once I have a chance to get some figures from the Mirage, I'll post them and decide which prop to keep.

 

[B-Faithful]

I think at the end of the day you may be like me... Wishing merc made the Rev 4 in a 16" pitch.

 

[Megabyte]

Agreed. I'm thinking that a 15x16 Rev 4 would be ideal. :wink:

 

[B-Faithful]

Hey, if anything the 15" Rev 4 looks good when the engine is raised :lol:

 

[Parker23]

How do you Prop Gurus think that 14 5/8 x 15 Revolution would be on a 23'deepvee sportcabin with a 200hp ox66

 

[Porkchunker]

Kevin,

Those numbers show why a 4-blade prop shines in the mid-range. 4200-4300 looks like a sweet spot in terms of speed and gph. It also has better "hook up" as you noted. And with 157 gal of fuel, it gets you out of the hole better. I believe for your normal use, being under propped a bit is not a bad deal. Just don't run it at WOT often.

 

[B-Faithful]

How do you Prop Gurus think that 14 5/8 x 15 Revolution would be on a 23'deepvee sportcabin with a 200hp ox66

Run your current performance through the merc site (they show Yammie outboards) and see what it comes up with.

IF kevin doesnt want the prop and you are interested, I could send you the prop to test. If it works out, we can make a deal. If not, you can send it back.