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Prop choice 1995 Dauntless 15 repower with F70
jgortva	#1  Posted on 11/23/15 - 6:52 AM
Member Personal Page Posts: 227 Comments: 1 Joined: 11/12/09	Made a deal on a F70 last Saturday. Dropping the boat off next week for the installation. I think I found a knowledgable dealer who has repowered quite a few Whalers. Tells me starting out at 2 holes up is no problem. We did not include a prop in the deal so I need something to get started with. I have read many threads but mostly on older Whalers with different hulls than my Dauntless which is pretty much a vee hull compared to my prior classic sport. My Dauntless also has Smart Tabs which work great and is the reason I am starting at 2 holes up and not the highest engine mounting height. Hoping someone here can give prop advice. Thanks Jim
Phil T	#2  Posted on 11/23/15 - 8:58 AM
Administrator Personal Page Personal Album Project Albums Posts: 6986 Comments: 6 Joined: 03/26/05	Prop selection is tied to the engine, it's WOT limit and the lower unit gear ratio. Following that you take into consideration the hull, average load of people/fuel/gear etc. This thread has the information. Don't get thrown by the different model whaler. http://www.whalercentral.com/forum/vi...rowstart=0
jgortva	#3  Posted on 11/23/15 - 10:31 AM
Member Personal Page Posts: 227 Comments: 1 Joined: 11/12/09	Thanks Phil, I really respect your input, but the thread has different members giving great performance figures mounting their engines both 2 and 3 holes up and has prop recommendations of the Stiletto Advantage, (which I am leaning towards) of 13 1/4 x 13, 14, and 15 pitches. I was hoping to narrow it down a bit. Thanks Again Jim G.
EJO	#4  Posted on 11/23/15 - 12:44 PM
Member Personal Page Posts: 669 Comments: 6 Joined: 11/25/12	Like Phil said it depends on your running conditions/weight.. If the 15 pitch doesn't let your OB come up to max RPM at WOT then you need less pitch, If the 13 pitch makes your OB run over max RPM at WOT you need a bigger pitch. Hard to figure out with our current weather here in the Mid-West. Good luck and hopefully your dealer lets you try each different pitch to determine your best set-up. Skipper E-J m/v "Clumsy Cleat" a 2008 Montauk 150
Phil T	#5  Posted on 11/23/15 - 1:29 PM
Administrator Personal Page Personal Album Project Albums Posts: 6986 Comments: 6 Joined: 03/26/05	I have found giving one prop as a suggestion is not always welcomed. If you want "the" prop, lets discuss in detail how your boat will be loaded and how it is run. Describe what performance characteristics you are looking for, i.e. high speed, quick hole shot with heavy load, general overall performance. Describe the load in the boat 70% of the time. How many people? Typical fuel load. How much gear (tools, safety equipment etc). How much stuff do you bring onboard? ice chests, fishing gear etc. Is the boat going to be used on Great Lakes? Small lakes or rivers? When it comes time to test the prop, I would take off the tabs for testing purposes. Only once you have the motor and prop dialed in would I install the tabs.
jgortva	#6  Posted on 11/23/15 - 1:33 PM
Member Personal Page Posts: 227 Comments: 1 Joined: 11/12/09	Skipper E-J, Thanks for the input. I understand the, "pitch" concept. However, my Dealer does not have a selection of props for me to try out. I was going to use Discount Dan to pick up a Stiletto Advantage 1. He will let you return a undamaged prop and exchange for another for a $49.00 fee. That is why I was trying to get close enough with a base line recommended prop to either only have to exchange once if the pitch is really off or have my prop guy re pitch it for me. He can repitch up or down a max of 2 inches which he has done for me in the past on other boats. Thanks Jim G.
jgortva	#7  Posted on 11/23/15 - 1:40 PM
Member Personal Page Posts: 227 Comments: 1 Joined: 11/12/09	Phil, The boat is used mostly on Lake Michigan loaded with me, (270 lbs), the wife, (160 lbs), wifes purse, (50lbs),good for nothing dog, (30 lbs), 12 gallons fuel, and not much else other than saftey equipment. I am looking for best all around performance as rarely does the boat go over 20-25 mph due to water conditions. While it is mostly a, "harbor toy", we do take cruises up to 15 miles to surrounding ports so mileage should be decent, however anything will be an improvement over my 1995 Evinrude 70 H.P 2 stroke that the Yamaha is replacing. Thanks Jim G. Edited by Joe Kriz on 11/23/15 - 2:04 PM
Phil T	#8  Posted on 11/23/15 - 2:30 PM
Administrator Personal Page Personal Album Project Albums Posts: 6986 Comments: 6 Joined: 03/26/05	Jim - Just so you know where this comes from. The goal is to prop the engine so that with the typical load, the engine's rpm's will get to or within 200 rpm's of the top of the WOT range. It is not that you are going to go that fast. This means the engine is performing right in whatever rpm's you choose. Since the Turbo model is NOT offered in 14 inch, I would not get it tweeked. I would go with the Yamaha Performance prop.
tedious	#9  Posted on 11/23/15 - 2:45 PM
Member Personal Page Posts: 1072 Comments: 2 Joined: 09/07/08	Jim, although the Stiletto Advantage is a great prop, I can tell you from direct, personal experience that it is a VERY poor match for the F70. I ran an Advantage for several years on my Supersport 15 and put up with lackluster acceleration and general blah performance, primarily due to procrastination. I finally got off my duff and switched to a Power Tech SCD3 last summer and the difference is astonishing - much better acceleration and improved top speed too, and no loss of mileage. I am not sure what pitch would be best, but if you go to the Power Tech website. find their contact info, and explain your situation, they will make a recommendation. They returned my request in less than 24 hours, in the middle of the busy summer season. Power Tech also will replace your prop with a different pitch for a nominal fee. After getting a recommendation from Power Tech, I did buy mine through Dan's Discount Props - they do not show the SCD3 on their website, but can order any of the Power Tech line. I am sure that the above sounds like I'm just promoting Power Tech, but I am not. I'm convinced that any prop with a lot of blade area is a bad idea for the F70, and possibly other 4-strokes that make their power at high RPMs. With the additional power needed to drive a V-hull, I would think the Advantage would be even worse on your Dauntless than it was on my classic 15. If you want to stay with props made by PPI, the manufacturer of the now-defunct Stiletto line, you might want to try the Turbo Quest - they advertise it specifically as being good for the F70, and it seems to have the same characteristics as the SCD3 - lower blade area, low rake. The Quest is available on Amazon - isn't everything? By the way, great choice! The F70 is an awesome motor, especially with the right prop! Good luck! Tim Edited by tedious on 11/24/15 - 6:14 AM
dauntless-n-miami	#10  Posted on 11/30/15 - 7:09 AM
Member Personal Page Project Albums Posts: 315 Comments: 0 Joined: 11/05/08	Hello jgortva, I currently use this prop make and model mentioned by tedious but on a late model Yamaha 90 2-stroke. Prop size is 13 inch diameter x 17 Pitch, I have seen a very noticeable improvement from this prop as compared to a Solas early model Saturn (round-ear-type) prop that I used previously. The Solas measured 13-1/4 inch diameter x 17 Pitch. From my signature you will gather that I too have a Dauntless 15, 1996 vintage. This particular Power Tech prop (SCD3) if I recall was recommended for the Yamaha 90 2-stroke according to the Power Tech website, you should verify application for an F70 if considering. Thought to share... Angel M. 1996 Dauntless 15, Sportsman Pkg. - 2007 Yamaha 90 HP 2-Stroke
alan heckmamleper	#11  Posted on 12/01/15 - 5:18 AM
Member Posts: 79 Comments: 0 Joined: 04/14/13	I have a 1999 Alert 17 with a Yamaha F70 on it and Tom Clark recommended a 13.25 x 14 Yamaha Performance Series 3 blade Stainless Steel prop with the motor mounted 3 holes up and IMO this is the perfect set up for my boat. I'm not sure about the Dauntless,maybe others can help, but it is perfect for the 17 foot Montauk/Alert hull.You will love your new motor, the fuel economy is unbelievable!
jgortva	#12  Posted on 12/03/15 - 6:03 AM
Member Personal Page Posts: 227 Comments: 1 Joined: 11/12/09	Thanks to all for the advise. The boat is in the shop and even though I wont be able to get it on the water for a while, I still cannot wait to get it back. Phil, I respect your recomendation highly for the Yamaha Performance Series, however after doing some online shopping that is not a cheap investment compared to an aftermarket SS prop after plunking dow 8 grand for the motor, controls, labor, guages, etc. I really dont want to be cheap, but is there any aftermarket SS prop you would feel confident recommending for my setup as the, "one" prop?
Phil T	#13  Posted on 12/03/15 - 8:52 AM
Administrator Personal Page Personal Album Project Albums Posts: 6986 Comments: 6 Joined: 03/26/05	You can start with the Yamaha painted stainless steel or their aluminum prop. If you choose one of these, the size will be different. If you do decide on the aluminum, I would get the dealer to throw it in for nothin. You are spending 8k for chripes sakes. If he balks, he's an idiot.
tedious	#14  Posted on 12/03/15 - 2:26 PM
Member Personal Page Posts: 1072 Comments: 2 Joined: 09/07/08	I believe the Power Tech SCD3 is a copy of the Yamaha Painted Stainless, but it is a lot cheaper. That is certainly "the one prop" that worked well on my F70. But if you are asking if anyone can guarantee you that a prop you buy will be optimal, the answer is no - it takes some experimentation. Tim Edited by tedious on 12/03/15 - 2:28 PM
bradsc	#15  Posted on 12/03/15 - 2:29 PM
Member Personal Page Posts: 118 Comments: 0 Joined: 01/15/11	I would try a Yamaha mar-gyt3b-v4-14. ( 13.25x14) This is what I have on my F70 on a 1998 Montauk. I have had 4 people on the boat, full cooler and gas tank. Pops right up. It is not a speed prop but getting around 7.8 mpg at 21 mph.
jgortva	#16  Posted on 06/20/16 - 6:09 AM
Member Personal Page Posts: 227 Comments: 1 Joined: 11/12/09	Sorry for the delayed response. Finally got to break in my F70 and found some smooth enough water to get some performance numbers. Ultimately I went with Tedious choice of the Power Tech SCD3 13 X 16 prop with my decision to have the engine mounted 2 holes up. The cavitation plate looks to be roughly 1 inch or so above the bottom of the boat. The engine performs great for my all around use as I rarely am able to get it above 20-25 MPH or over 3000 RPM due to water conditions and in those conditions it cuts thru the chop easily. However, the full out performance is lacking. With 2 persons, safety equipment, and 96 pounds of fuel for a total of 551 pounds on the boat, WOT topped out at 30 MPH at 5000 RPM's. The range Yamaha states as optimum is 5300-6300 RPM, which to me is a pretty wide range. I would like to stay with the Power Tech brand of props as Dan's Discount Propeller very generously gave me a trade in period where I can pitch up or down for very little cost. My question would be, should I be looking maybe at a different blade diameter as well as pitching the prop down? I have seen the SCD3 in 13.25 diameter as well as the 13 I have. Also any other theories would be appreciated.
tedious	#17  Posted on 06/20/16 - 10:50 AM
Member Personal Page Posts: 1072 Comments: 2 Joined: 09/07/08	Jim, diameter isn't really a variable - you get a prop which is the proper diameter for the motor, and that's it. I would be inclined to drop down in pitch, possibly all the way to a 13, and see how that works for you. With your usage model where you can't go that fast much of the time anyway, that will give you a nice low gear for power, and it should get you up in the RPM range where that motor will sing. For reference, the trade-in for a different pitch policy is standard for Power-Tech - one of the things I like about them. Tim Edited by tedious on 06/20/16 - 10:54 AM
Joe Kriz	#18  Posted on 06/20/16 - 11:29 AM
Site Owner Personal Page Personal Album Photo Albums Project Albums Posts: 11430 Comments: 452 Joined: 03/18/05	We buy props by Pitch. The engineers take care of the diameter. Here are some basics: http://www.whalercentral.com/articles...cle_id=108 If you change brands or models of props, then you would need to start over or follow others with the same prop/motor combination.
jgortva	#19  Posted on 06/20/16 - 2:53 PM
Member Personal Page Posts: 227 Comments: 1 Joined: 11/12/09	Joe, I appreciate your input and I understand about staying with the same manufacturers blade design. I just added the blurb about staying with Power Tech so I wouldn't have to fend off any advice for other manufacturers props for this very reason. Tedious, I thought diameter was also governed by the size prop that would fit on the gear case. I guess then my next question would be why prop manufacturers including Yamaha make multiple diameters from 13, 13.25, and 13.50 for my F70. Will the lower pitch improve top end? It seems like the higher pitch would have a higher top end but a longer planning time while the lower pitch would have a shorter planning time but a slower top end speed? Jim G. Edited by jgortva on 06/20/16 - 3:06 PM
Joe Kriz	#20  Posted on 06/20/16 - 3:25 PM
Site Owner Personal Page Personal Album Photo Albums Project Albums Posts: 11430 Comments: 452 Joined: 03/18/05	The SCD3 is only available in 13 inch diameter for your motor.. Again, we only have a choice of pitch with any given brand of prop. http://www.ptpropeller.com/content-pr...amaha.html You have a 16 pitch SCD3 prop. Less pitch will give you more RPM's at WOT and usually slower top end speed but a faster hole shot. More pitch will give you less RPM's at WOT and usually slower out of the hole but faster top end. It sounds like you need less pitch, like an SCD3 15 pitch prop (maybe even a 14 pitch) which will increase your RPM's at WOT. As it is right now, you are at 5000 RPM and you should be 5300 to 6000 RPM's. I would try the 14 pitch during your trials and trying different SCD3 props. See the diameter of all the SCD3 props which is 13 inches. Below is the SCD3 R14 pitch prop for Yamaha motors.. Joe Kriz attached the following image: [66.22Kb] Edited by Joe Kriz on 06/20/16 - 3:28 PM