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tasthree

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Not sure if this is the right place but have Another prop question here. I know enough to know I don’t know enough about props without seeking advice for my situation. I have called a couple of places and I even emailed Solas with no response from them. So first some info about the boat which is aluminum built for a 25 HP max lake near us. It is a 1982 Smoker Craft Big Fisherman that is 15’4” long, I think 72” wide and a 21” transom. It has a v bow that transitions to being flat at the stern. It came factory with a splash well, pedestal seats, bow storage, a live well(used for a soft sided cooler and storage) and a storage compartment on the port side with a rod locker on the starboard side. It had a side console and wood floor. The console and controls were removed to lighten and to make more room for fishing. The plywood transom core and rotted wood floor were replaced with Nida Core that was glassed and marine epoxied. The floor carpet and alum railing on the bow were removed to lighten it some more. There isn’t very much info on the net about the boat and Smoker Craft never replied to my inquiries about it. I believe the hull dry weight was about 540lbs but I don’t know what it is after being modified. A 12v Terrova trolling motor is on the bow now with a 27 group battery in the bow compartment. A 2018 Yamaha F25 tiller that is electric start with manual tilt hangs on the back. The starting battery and a 6 gallon gas tank tuck under the splash well. The transom is 21 degrees and the motor would only tilt 15 degrees so some wedges were added to tilt the motor out to provide more bow lift. The motor was raised up so the AV plate is about even or a little above the bottom of the boat. With the motor in the last pin out and while under plane the AV plate is above the water line. I’m guessing that the total weight of the boat as it’s ran is over 11-1200 pounds. The motor has a 5-6000 RPM operating range with a 6200 rev limiter.
Now the details for the three props I have that were tested the same day on a lake that was flat calm . I had 200 pounds of sand in the boat to simulate the wife and our dog. The motor came with a Yamaha 9 7/8” x 11 ¼ pitch prop. At wot it ran at about 5140 RPMs and 21.7 MPH. I tried a Solas Amita three 9.9” x 9 prop. It will hit the 6200 RPM rev limiter with throttle left over and tops out at about 20.8 MPH. Next was a Solas Amita three 9.9” x 10 prop. Top RPMs were about 5850 at about 22.7 MPH. I then took the sand bags out and with the 9.9” x 10 Solas prop I hit about 6040 RPMs and 24.8 MPH which is perfect when I’m by myself. All the props got up on plane good and I could turn as sharp as I dared with no blowout.
Now the issue. I’m trying to be as close as possible to 6000 RPMs at wot to be in the best power band of the motor. I seldom go out on the boat without the wife and dog. With them the Solas 9 is to small and always hits the rev limiter leaving a unknown amount of throttle left over. The 10 drops out of the best power band RPMs especialy when it’s windy and or we go up the head rivers against the current. There is at least 350 or probably like 500 or more RPMs difference between the Solas 9 and 10 pitch props. I need something that would be somewhere in between them. I have no prop shop near me. One place I called said I could ship them my Solas 9 pitch and they could add some ?cup? to it to lower the RPMs. I want to keep that prop in case I have a bigger load and need the smaller prop. Forgot to ask if they could get at least 200 more RPMs out of a Solas 10 pitch. The factory Yamaha 11 ¼ prop is too far off and is completely useless to me. I tried doing some kind of trade with it at my nearest dealer which is almost an hour away. Even though it’s still like new they wouldn’t do any kind of trade for a 10 ½ pitch. I wasn’t willing to pay the $150 + tax they wanted for the Yamaha 10 ½ pitch just to try it. Thinking I’m going to have to sell the 11 ¼ on *bay. Any thoughts/ advice from anyone with more prop experience on small horse power motors. What would be the best route to go? Have a Solas 10 reworked for more RPMs or get a 9 reworked to get less RPMs? Try the Yamaha 9 or 10 ½ or some other brand? From what I understand a four blade will lose me top end which I’d like to keep as much as possible so I feel a four blade is out. Don’t want stainless because of the cost and I’m always exploring skinny waters so afraid of hitting things. Thanks .
 
That 10 is pretty close to where I’d want to be. As far as prop brands I’ve used Solas because of the price, I had trouble finding a prop I liked on my Mercury 25 hp 2 stroke, I tried a Turning Point Hustler and am impressed. It has more cup, a lot better bite than the Solas at low rpms. I use an 11 pitch for heavy loads. But I think my motors has a different ratio than yours, the stock prop is a 13.


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That 10" solas is where I'd be if I were choosing between those 3.

But if you went with a turbo or even a Powertech, you might find another mph or so. Big deal. If you have access to one in a 10", try it. Also, if you have access to the Yamaha 3x9 7/8x10 1/2, you might try that-they are VERY good. Actually within a half MPH at nearly the same RPM as the best SS I've tried which is a Turbo. Still looking for a Powertech to try. Solas was the slowest of all of the SS props I've used, but it had good manners while getting on plane.

If you go over 6000 a little don't sweat it. You can always back off the throttle a little if you need to.
 
I have a Powertech SRA3 10" pitch that came with the Yamaha 30 I just bought. The motor is a longshaft and I ran it on my 15" transom 1648 with a 7" setback Panther tilt and trim unit. I was getting 27mph and 5800 rpms with two people even though the motor is at least 5-6" too low still. Not sure how much more I can expect from it being set up correctly but I will likely be going up in pitch after I do get it ironed out.

My motor is a 1988 model 2 stroke but I think we have the same 10 tooth spline prop shaft and 3" gearcase. Maybe someone else can confirm compatibility, but if they are and you would be interested in buying send me a message. Still can't say if I will actually sell it or not but I should have a better idea in the next couple of weeks. I know playing the prop game gets expensive and does involve a little luck.
 
Did you try running your rig (OB & boat) though the ‘prop calculator’ I added as a sticky post in the motors forum?

I have propped many boats using that and they all were DEAD nuts accurate, awesome performance attained!

Adding to that, and I personally have never seen a Solas prop worth putting on a boat, unless you needed a lightweight drift anchor. I hear they make good waterjet impellers though ...
 
ktoelke54. Yes the 10 is close and is what I have been using but if we get into a headwind and or a current the RPMs drop down to 5700 or below. Acceptable but still could do better. The 9 would still be hitting the rev limiter. I have learned on small HP motors that the 200 RPMs per 1" of pitch is way off. More like 5-600 Rpms or even more. Tubrotodd & wmkoo2 I don't have any personal experience but I have read that stainless is more likely to damage my LU if I hit something. Think I'll stay with Aluminum. I'm at least going to sell my 11 1/4 Yamaha prop and look for a used 10 1/2 to try. Anyone have real data on RPM difference between the Yamaha 11 1/4 and the 10 1/2 pitch props. Daleh. Yes I did run it thru the calculator. Multiple times adding weight each time. Smallest it said was a 10.375 x 11 which seems similar size to the Yamaha Prop I have which is way to big. I don't know about the average quality of Solas props. Seems most reviews rate them ok for the price point. At my HP I didn't think build quality would make that big of a difference to pay two or three times as much for other brands. It's not like I'm racing or such. I am an old gear head so it's just my nature to try to improve the performance. :wink: Been having health problems with a lot of bills. :( I was just trying to save a couple of bucks for now on the Solas because ordering different prop sizes for testing can get expensive. Wish I had a dealer nearby that would let me test different props. My nearest dealers are used to people with BIG bucks so I'm not worth their trouble. A $150 prop to them is like lunch at the members club. :roll:
 
tasthree said:
I was just trying to save a couple of bucks for now on the Solas because ordering different prop sizes for testing can get expensive. Wish I had a dealer nearby that would let me test different props.
Buy 1 Turning Point prop and they'll send you another size to test for $35. I've never had to get a 2nd prop from them, after using their calculator and buying one of their newer 'pressed' aluminum props, that gives SS performance at an aluminum prop price!
 
tasthree said:
Anyone have real data on RPM difference between the Yamaha 11 1/4 and the 10 1/2 pitch props.


Yes. On mine it's about 300 RPM difference.
 
Daleh. I even tried calling Turning Point with no answer. I don't leave messages cause seldom am I called back. It appears that the smallest prop they have listed is the 10.375 x 11 prop. I do not see how that will get me 860 RPMs over the Yamaha 9 7/8 x 11 1/4 prop. So I have given up on them unless you can find a smaller prop they make. I have tried. Maybe Google is changing my algorithms :LOL2: . Kdgrills. Your boat is smaller than mine and assuming less weight. Your max RPMs were 5400 compared to my 5140. Based on your results I don't think the Yamaha 10 1/2 will get me to where I want to be. You gained 700 and I need at least 860. Guess I'll skip that thought. Turbotodd. Whats your boat specs. Might as well do this thread for future reference for others. Thanks. Might give JT's props another call.
 
Talked to a engineer from Turning Point. He confirmed that the 10.375 x 11 is the smallest alum prop they have for my motor. He also confirmed that I wouldn't gain much if any over the Yamaha 9 7/8 x 11 1/4 prop. He also said Solas props were of reasonable quality and suggested that I just have one of my Solas props reworked. Daleh. Just wondering what it is about Solas you don't like when you said you have never seen a Solas prop worth putting on a boat? The metallurgy, geometry, country of origin and does that include every model they make?
As of this point it looks like I am going to have to have a prop reworked. So is it better to take Rpms out of a prop that is to big or to add RPMs to a prop that is to small?
 
Solas aluminum props are made of a real thick cast material. Thicker blades=more drag. You'd think being thick, they'd be strong but I haven't seen evidence of any more strength than the factory yamaha props that people like to replace with solas cheapie aluminum. When a blade breaks off, look closely at the casting. It's real porous. Lot of guys run them and most everyone I have talked to says the same thing, they're cheap and they're inexpensive. No other input. Only one I ran was a 4 blade Amita 4 in 10" pitch which ran real smooth but lost almost 6 mph over the 9 7/8 x 11 1/4. I can give up some speed but I aint' giving up 6 mph. Sold it to a guy up the road and he likes it for what he uses it for which is mostly idling around.
 
Somewhat same experience with Solas, just so, so performance. Then the last one I bought was really sub-par. It was a 12 pitch 4 blade Amita. It had lousy bite and was out of balance to the point of not being usable. It seems to me that they should be able to test a prop for balance before shipping.


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Talked to a couple of prop shops today asking for advice and looking for used Yamaha props. The consensus was it is easier/cheaper to lower RPMs on a smaller prop by adding cup. Most said the Solas props were ok. I do know that compared to my Yamaha prop the Solas blades are thicker and don't taper to the leading edge as nice. Would anyone have numbers from using a Solas 9.9 x 9 and a Yamaha 9 7/8 x 9. I read on another forum where someone had tried the 11 3/8 x 12 Solas and Yamaha props with the Solas at 400 more RPMs. To me this indicated that the Yamaha prop had more bite. If I could drop 300 RPMs or so with the Yamaha 9 verses what my Solas 9 gives me I think it would put me close enough to where I want to be. I have to call back a prop shop tomorrow to see if he found anything. If not I found a source that has a new Yamaha 9 pitch for $102 shipped that I may order to try.
 
Talked to the prop shop guy this mourning. He didn't have anything. He said those 11 3/8" props are a different design and that I can't use the different results between the Solas and Yamaha on them with my 9 7/8" props. I went ahead and pulled the trigger on a new Yamaha 9 7/8" x 9 and hope that it bites a little more than the Solas 9 I have does. If not then I'll have the Yamaha prop reworked. After I get the prop in and tested I'll post the results.
 
Got the new Yamaha 9 7/8” x 9 pitch prop and have been out a couple of times with it. Top speed is about 21.7 MPH when it starts to hit the 6200 rev limiter. It bites better so it is almost 1 MPH faster than the Solas 9 pitch and there isn’t as much throttle left over before the rev limiter is hit. If I had a prop shop nearby I would take it in to add a little cup to it but I’m not going to pay for two way shipping to have it done. Going to use it as it is. I did some measuring and found the Solas 9 prop is 2.2 oz heaver and one of the blades is about .020 short. On the Solas 10 pitch one of the blades was .064 shorter than the other two. The Yamaha was pretty even. Was it worth it to buy the Yamaha 9 prop on top of the Solas prop I already had? In the long run I think it will be. If I had found the Yamaha 9 prop I got for $102 first I wouldn't have bought the Solas 9 Prop. I don’t know what the overall RPM difference would be for someone trying to figure out what prop size to go with. With the Yamaha 9 I hit the 6200 rev limiter with a little throttle left over and the Yamaha 11 ¼ was at about 5140 RPMs WOT. That is at least 1060 and I would guess closer to 1200 RPMs or more difference. I would still like to try the Yamaha 10 ½ but I’m not going to buy one because I think it would leave me at least 300 RPMs short of where I'd like to be. I guess I'd rather have to back off the throttle a little to keep the motor in it's power band than to lug it with a prop to big. I would also assume keeping the RPMs higher would up the alternator output to help recharge my trolling battery between spots. And yes even with the small 18A alternator on my motor and the Yandina combiner I can tell it helps. That is another topic though. Hope this little experiment helps someone figure out a little better on what prop to go with on a smaller HP motor.
 
My Yamaha dealer will let me buy props and return them in perfect condition so why wouldn't yours?Did you buy the motor there?My friend has a F25 on 15' rivetted boat with wood floors and with two 200lb men will see 25mph at wot without hitting the rev limiter(no tach) with a Yamaha 9 7/8x10 1/2 alum.Start with the 10 1/2 I'd say. m.w.
 
The Yamaha dealer I bought the motor at is almost two hours away. I tried buying off a closer dealer but they wouldn't come down on their asking price at all. Over 1k difference. It's the same dealer that I tried doing some kind of prop trade with. I feel they are used to people with big money and I wasn't worth their time. I'd like to try a Yamaha 10 1/2 but I don't think it will get me any closer in rpms to where I want to be than the Solas 10 is. If I find one for a good price like the 9 was I may go for it. I guess at this point I'd rather have to back off the throttle a little than to lug the motor. I may go visit a friend who lives on a lake with a prop shop nearby and have my props worked on a little. It's not like I'm racing or such. They lakes we are usually on are fairly small so a couple of MPH won't make that much of a difference. But I am a old gear head and like to get as much as I can from the setup I have. :)
 
I guess I just couldn’t resist it. I found a new Yamaha 10 ½ pitch prop for a reasonable price. Got to run it and see what it would do. It was a windy and choppy day when we got to the lake so things weren’t so good at first. At times it would only hit 5500 RPMs or so. Went up the river and fished most of the day using the electric motor. The wind had laid down by the time we were leaving. The best it did was 5860 RPMs and 22.5 MPH. Still at least 250 RPM's short of where I’d like to be. So to recap the Yamaha aluminum props on my boat. The Yamaha 9 7/8” x 11 ¼ pitch that the motor came with topped out at 5140 RPM's at 21.7 MPH. The Yamaha 10 ½ pitch topped out at 5860 RPM's and 22.5 MPH. The Yamaha 9 pitch would hit the 6200 RPM rev limiter with a reasonable amount of throttle left over and a top speed of about 21.7 MPH. I never got in conditions where I couldn’t get the 9 pitch to hit rev the limiter with some throttle left over.
In my Yamaha owner’s manual it says “Next to selecting an outboard motor, selecting the right propeller is one of the most important purchasing decisions a boater can make.” So I don’t know why Yamaha went from the 11 ¼ pitch to the 10 ½ then jumped to the 9 when these small HP motors are affected by pitch so much. I need something between the 9 and 10 ½ pitch. Hello Yamaha! How about a 9 3/4 pitch prop. I really like this motor and it does what I want from it. For me I just feel it’s potential is hampered from the aluminum prop selection I have found/tried. The wife said I’m done “no more props”. She didn’t say I couldn’t have them worked on :wink: . If I’m ever going to be in a area that has a prop shop I think I’ll take a couple of them to get massaged a little. So for now I guess I’ll have to stick with the Yamaha 9 pitch and have to back off the throttle a measurable amount to keep it in the RPM sweet spot and not over rev it.
As a side note also I finally found a brochure for my boat. With that I realized my boat is a little heavier than I thought. It was available as a tiller and a optional side console and remote control. A rep at Smoker Craft said the weight listed is as a tiller. Our boat had the option which I have removed. The option only added about 25lbs or so. Enough to be of mention I guess.
Hope this helps someone in a similar situation as me trying to figure out prop selection. I also wish Yamaha would reevaluate their prop selection. They go thru the time and expense to redesign a motor but choke it with a gap in their prop selection :? .
 
Yamaha owns turbo.

That is why the "factory" white aluminum prop jumps from a 9" to 10 1/2". You can buy a 10" turbo hotshot which should be pretty close to what you're looking for. I'd expect to see 6050-6100 RPM with it, depending on weather and water conditions. It should be VERY close. Might even pick up a little speed over the 10 1/2" white prop.

Those white props are "cheap" replacements and nothing more. The 10 1/2" came on the old 4 stroke 25's. The 11 1/4" came on the '17+ 4 stroke 25 and all of the 2 stroke twin carb 25's. They were designed to be an "all around" prop. There is no 10" or 9 3/4" because there was no use for it in a production standpoint. The 9" was mostly for pontoons and such that can't use the 10 1/2". I've never had an application that couldn't use the 10 1/2 or 11 1/4" but most of what I see is flat bottom Jons from 14' to 16'.

I'd be satisified with 5850 RPM, that's right in the ballpark and it may go up or down depending on water, wind, altitude and/or weather changes.

Had mine into the shop last week to do maintenance. Did you know that the ECU logs "how" the engine is used? Mine showed a graph of how many hours at each RPM range it was operated. I think it was 6.4 hrs from idle to 2000. 2000-3000 was 6.2 hours. 3000-4000 2.8. 4000-5000 5.6. 5000-6000 2.4. 6000-6200 (was in red) 0.9 hr. Oh and it showed to have been shifted 314 times (includes forward to neutral, neutral to reverse, vise versa). Interesting. Same day we had a guy bring an F90 in for "inspection" and during an ECU check, found that it was used from idle to 2000 RPM over 90% of the time which I found interesting. It showed 181 total hours. I guess hes' trolling a lot, didn't ask.
 

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