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Highfive Propeller for Dauntless 18
|Author||Topic: Highfive Propeller for Dauntless 18|
posted 07-19-2005 08:44 PM ET (US)
I've done a search for propellers and read several good threads that touch on the subject.
My situation is this:
I have a 135hp Optimax with a 3 blade MiragePlus 17P. I want to buy a spare propeller to have onboard. Rather than duplicate the MiragePlus, I went to Mercury Marine's website and used their lame propeller selector.
I then called two different propeller suppliers and got the same recommendation from both: Highfive 13.5 x 17.
From what I've read and what I've been told, it appears as though I should stick with the same pitch as is currently on the motor (17P). At 3500 rpm, I run at 25 mph and WOT at 5500 rpm and 40+/-. Is this correct?
Also, from what I've read and been told, the out of the hole performance should be stellar with the 5 blade, it should be smoother (I do have low speed vibration with the 3 blade MiragePlus) and there shouldn't be too much, if any sacrificed on the top end. Is this correct?
I've read several posts here regarding selecting the correct propeller for the motor: i.e. not being able to achieve maximum rpm or have a prop with a size and/or pitch that put too much of a load on the engine. If I go with the 13.5 x 17 Highfive, will this be the case? I've been told not.
Finally, I run in some rough choppy water for a 18 foot boat. Keeping the boat on plane at 3000 rpm trimmed in is sometimes difficult. From what I've read and been told, the Highfive should help with this problem in rough water.
Thanks in advance.
posted 07-19-2005 10:04 PM ET (US)
From what I have read, most people are very disappointed in the High-Five. You are right that you will have a great hole shot, but every other parameter suffers especially the top end. Now, if you are a hard-core water skier you might be happy...that’s what it is for, slow and steady. Try a four blade for smoother running without loosing too much near the top.
posted 07-19-2005 10:19 PM ET (US)
If I went with a four blade prop, I am assuming that I should go with the Vensura (offshore series)???
VENSURA (OFFSHORE SERIES)
For single 135 - 175 hp outboards - aluminum multispecies fishing boats
posted 07-19-2005 10:34 PM ET (US)
Sounds better to me.... I run a Power Tech UN200OFS4R17P on my 150 Opti and I am happy with it. I replaced a Mirage 17p.
posted 07-20-2005 08:13 AM ET (US)
If the High Five is really what you want, double check the pitch sizes currently available. When I was considering one, I saw on the Merc site that it was made as low as 17 pitch. Then I went to both my dealer AND various online prop sources...the lowest High Five I could find was 20 pitch. This info might have changed recently but I believe Merc's intent is to supply them down to 17P in the near future but I think currently, they are unavailable in pitch sizes below 20.
posted 07-20-2005 08:49 AM ET (US)
17P is available in the HighFive.
posted 07-20-2005 09:25 AM ET (US)
"Finally, I run in some rough choppy water for a 18 foot boat. Keeping the boat on plane at 3000 rpm trimmed in is sometimes difficult. From what I've read and been told, the Highfive should help with this problem in rough water."
I have the same setup and run in rough seas as well. You might consider raising your motor up 1 or 2 holes as it really makes a huge difference in the boat and motor performance under those conditions. My motor was delivered mounted all the way down and I raised it 2 holes.
posted 07-20-2005 09:32 AM ET (US)
I tried a 17" High five on a boat I had that was originally propped with one of the old Mirage's, also in 17". the high five behaved like it had 2-4 inches less pitch than the Mirage. IE, RPMs were about 3-400 rpms higher at any given speed across the board. If it were me, I'd go up 2 inches in pitch on the high five as a starting point. BillS
posted 07-20-2005 09:52 AM ET (US)
bigjohn, the High Five starts at 20" pitch (and up in even numbers) in the midrange gearcase size, which I believe is up to the 115 HP engines. For the larger engines it's in odd numbers.
posted 07-20-2005 11:58 AM ET (US)
I'm backing away from the Highfive and focusing on the four blade Vensura as described above.
This morning, I tested the WOT RPM value of the existing MiragePlus 17P which resulted in 5500 rpm and 41 mph.
So, I can conclude that the 17 is the proper pitch for the boat right?
Now, Mercury suggested that I go down one pitch to a 16 if I go to the four blade.
Does anyone have any experience with the four blade?
posted 07-20-2005 06:06 PM ET (US)
Marlin, thanks for the info..I did not realize that.
posted 07-20-2005 07:43 PM ET (US)
Please explain why the prop selector is lame.
posted 07-25-2005 12:53 PM ET (US)
The prop selector on the Mercury site always recommends a pitch that is way too high. For my twin Opti 135/Conquest it recommends a 23 pitch. I currently run 17 pitch which places me in the right RPM range. Running a 23, would place me way out of the theoretical range.
posted 07-25-2005 03:55 PM ET (US)
I ran the Merc prop selector for my Nantucket. I used the weight instead of the total length choice. One of the props it selected was a Mirage 17. I ran a Mirage 17 on my Nantucket at one time and the numbers were fairly close. I also ran it for my Action Craft and it was right on. For fun, I ran the numbers on a Conquest 235 w/twin 135's and came up with 19 to 21 inch props, not 23. Seems that you must to select the correct hull type and use the TOTAL weight, not the length for BW style boats, and then it’s fairly close.
posted 07-28-2005 10:29 PM ET (US)
After extensive research, calls to Mercruiser and Whaler along with the help of some others on the forum, I have ordered a 17P Vensura Four Blade.
Upon its arrival, I will report my findings.
Thanks to everyone who provided assistance.
posted 07-28-2005 11:05 PM ET (US)
I'll second what dgp states about Merc's prop calculator. Maybe its spot-on for some boat and engine combinations but not all. Unless I am using it incorrectly, it seems to recommend way too much pitch. I said the heck with it and took recommendations obtained here on the forum - I have not been dissapointed and my engine is operating in the correct rpm range.
posted 07-31-2005 05:56 PM ET (US)
Well, I put the new 17P Vensura on the 135 Opti today to see what would happen.
Preliminary results are as follows:
Loss is Speed from mid range to high end: 2-3 mph
Out of the hole: Nearly instantaneous...a significant improvement over the 3 blade Mirage Plus
Vibration: In gear, idle, the prop produces a low frequency vibration...(is this normal?) At 800 rpm, it smoothes out and vibration is gone. I noted some mid range vibration, but wasn't sure what it was exactly. I thought the four blade was supposed to be smoother than the 3 blade? Do you think if I removed the prop and reseated it on the shaft by rotation it a few splines it would make any difference?
Handling: no more skidding sharp turns. The prop really holds the turns much better.
Mid range acceleration: the boat just launches when fuel is added to the fire.
Top End Speed: Looks like 3 mph drop.
Wide Open Throttle: 3 blade MiragePlus: 5500 rpm
Rough Water Performanc: This is the one area that REALLY suprised me. The boat holds the water much better with the four blade. Now, can someone explain why this is?
posted 07-31-2005 07:05 PM ET (US)
Its performance nearly as my Power Tech's. Actually Power Tech's is a clone of your Vensura, so I would expect similar data. I am told that the reason for the better holding is...more blades in the water while in the rough stuff. Sounds like you could use another inch of pitch in your new prop. If it was mine I would have a prop shop increase the pitch slightly, you will gain back almost all of your WOT speed loss, midrange speed should be better than the Mirage and you will stay off the overspeed limiter. As for the vibration...I dunno..it should be smoother. If 2 props have had the same/similar vibration, then I would look somewhere else, but I don’t know where, maybe some here can help.
p.s. I had a really good prop guy tell me that the Mirage props he has seen have significantly more pitch than advertised.
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