Prop

[tasthree]

Tubrotodd. Isn't the Turbo Hot shot stainless. I'm just an average Joe and when out of my pay scale I try to rely on others experience. After spending hours and hours reading up on things, I thought the consensus was to not use stainless on small hp motors because of weaker lower units. Being that an aluminum prop gives a weak point over a stainless prop. That is why I was going with aluminum. Plus the Turbos are twice or more the price. Maybe I'm completely wrong. I don't feel like putting that theory to test as I have already slightly nicked one of my props. Where I'm at they drain down the lakes every year for winter( a lot and fast) so the head water river goes down also. I'm still learning the area for these level changes. I miss judged how far down it was a couple weeks ago and barely hit the one rock right that was right in the middle of the river #-o. It was enough to chip off some of the paint. Not going up that far up the river again unless I tilt the motor up or on the electric.
I don't know what boats the 11 1/4 , the 10 1/2 or the 9 were designed for or what performance they get. I do know what they do on my boat. Cheap replacements or not , to me there is to big a gap between the 9 and the 10 1/2. That 5860 with the 10 1/2 was the max it ever hit. I was hugging the shore line then and I don't know which way or how much the wind was at that point. The wind swirls around and down thru the ravines on this mountain lake so it's hard to tell at times. I go by how the prop does through out the day. If I got into any wind and or chop the 10 1/2 fell off to 5500 RPM's which is to low to me. The perfect prop to me would hit about 6200 at wot in calm water leaving me some Rpm's to drop for the conditions and still be in the ballpark. I don't know how many RPM's the 9 is leaving me short because it hits the rev limiter with a good amount of throttle left over.
I figured with today's technology they could do that. Another reason why I want to run it in the upper Rpm range. If I ever had a problem don't want them saying I was lugging it. Don't know if it helps in the long run but once in a while when trolling I stop and get up on plane and blow it out a little.
Guess I'll give Yamaha a call again about props and RPM's. Maybe I should even email them so I could have their response on record. :roll:

 

[turbotodd]

The "consensus" with SS is still somewhat of a myth.

If you hit something hard with aluminum, it's gonna bend or break a blade and it still can (easily) bend the shaft. If you hit something with stainless, it'll ding the blade(s), but it isn't as likely to destructively bend a blade, it won't break (usually) and it still might (or might not) bend the shaft. If you're in an area that has lots of obstacles, just be careful...simple as that. If the rig is insured don't worry about it. Besides, for the last gosh I don't know how many years, props have been manufactured with rubber hubs in them which will absorb quite a bit of shock. That wasn't the case with the old shear hubs, as well as solid-mounted hubs.

Yes the hotshot is SS, and the blades are strong and thin; has a little cupping on the trailing edges so you can run a little higher-and a little faster, with no loss in low end if the correct pitch is chosen. Also if you order it at a Yamaha dealer (if they don't have one in stock), Turbo (a division of Yamaha) will send it to the dealer with free shipping, but if you order it from a non-yamaha dealer, you're gonna get hit with shipping. Might save you a few dollars.

You "should" see max RPM with a slight shop. Calm water should be 50-100 RPM lower if it's set up properly. Also, you're going to see MAX rpm on a "cold" engine, one that's been sitting a few hours so that the air under the cowling is cool. Once it heat soaks, the temp sensor on the EFI pulls a degree or two of timing which will slow it down a little-that is normal, and to be expected. Mine will see 30 mph right off the trailer. After a 10 minute run to the "hole", limiting out, then heading back, I'm down to 29 or a little less and about 100 RPM difference. Remove the cowl and it'll run against the limiter at 30 again, but chance getting some spray up in it's nostril-which isn't good for the engine.

 

[tasthree]

I know this is an old post. I’m the op so I figured I could revive it if I had new info to post. I thought it might help someone if they were trying to figure out their prop selection.
We have been running the boat mainly with the factory Yamaha 10 ½ pitch aium prop on it. At times I’d put the Yamaha 9 pitch on. These props still left me feeling short of where I’d really like to be and wanting better performance. Then come’s along the covid checks. Even though I contracted covid we were blessed with limited impact from it. We spread the love around by donating some of the c money and yes I also decided I wanted to try another prop.
I reread some old post I had book marked, researched some more, made some phone calls etc. Learned about prop slip in the process also. I was getting like 19.68 % slip with the Yamaha 10 ½ p. I felt that was way to much and was a deciding factor to try another prop. I was going to try a Piranha composite prop but ended up ordering a SS Power Tech SRA3 in 9 pitch. Power Tech got their start with small engine props and there are a few threads on the skiff forums mentioning these props. Thought it was a no brainer. I had called and talked to them a couple of times. Was told the old rule that going from alum to stainless you drop one pitch to stay at the same rpms. I needed to gain about 400 rpms on the alum 10 ½ pitch. The techs said the SRA3 in 9 pitch should put me where I wanted to be.
It was a long four weeks waiting for the new prop. I was giddy when it finally arrived. Opened up the box to a sweet looking polished SS prop. Couldn’t stand it and went out and installed it. The weather cooperated that weekend so we went to the lake. Launched the boat, let the motor warm up while getting things ready, put it in gear to leave and oh my. There was more prop chatter than with any of the alum props I’ve tried. These new 25 HP fuel injected Yamahas are known for low rpm shake but it was a bit too much for me. Drove around some but the performance was not what I wanted. It had a hard time hooking up when going straight let alone in a turn. When I could get it settled in at full throttle it would only turn 5660 rpms at 21 mph. That’s like 9.45 % slip which is good on paper but just not the rpms and mph I wanted. I was thinking I’d gain at least a couple hundred rpms and maybe a mph or two not lose them. Knowing the performance I wanted wasn’t there we went back to the ramp to switch out the new prop. Didn’t want to take the chance of damaging it so I can sell or return it. Anybody need a SS prop.
We are always beaching the boat to take a break from fishing and to let the dog run. A few times we’ve gotten into some shallow water. As a result the outer edges of the 10 ½ alum prop got worn down slightly from hitting mud and small rocks. It didn’t look like new anymore. So while waiting for the new prop to come in I decided to give it a little tune up. I sanded the leading edges down to a taper some and removed any casting boogers. When I took the new SS prop off at the ramp I put this one back on. Same day, same load and conditions it hit 5920 rpms at 22.7 mph which is 19.79 slip. More rpms but more slip. Don’t know if I want to go thru the trouble of trying the piranha prop now.

 

[airshot]

You were 40 rpm above max with the 10"... how close do you expect to be?? Anyone within 40 rpm would consider that a sucess! Being slightly over max rpm with your lightest load is ideal, it will take a custom prop to get it right on the money, and if you do...for what,mabey 1 mph ?? If you want to be perfect get power trim and tilt then you can tune your motor position to get max performance. On my tinnie the power trim can make a three mph difference depending on water/ wave/ load conditions, something a prop cant do..

 

[Randaln]

You were 40 rpm above max with the 10"... how close do you expect to be?? Anyone within 40 rpm would consider that a sucess! Being slightly over max rpm with your lightest load is ideal, it will take a custom prop to get it right on the money, and if you do...for what,mabey 1 mph ?? If you want to be perfect get power trim and tilt then you can tune your motor position to get max performance. On my tinnie the power trim can make a three mph difference depending on water/ wave/ load conditions, something a prop cant do..

To be within 500 rpm would be a success..
IF YOU THINK tasthree was bitching about things before..
Wait till he tries a plastic propeller
Junk imo..

 

[Randaln]

To be within 500 rpm would be a success..
IF YOU THINK tasthree was bitching about things before..
Wait till he tries a plastic propeller
Junk imo..

 

[moedelawn]

The "consensus" with SS is still somewhat of a myth.

If you hit something hard with aluminum, it's gonna bend or break a blade and it still can (easily) bend the shaft. If you hit something with stainless, it'll ding the blade(s), but it isn't as likely to destructively bend a blade, it won't break (usually) and it still might (or might not) bend the shaft. If you're in an area that has lots of obstacles, just be careful...simple as that. If the rig is insured don't worry about it. Besides, for the last gosh I don't know how many years, props have been manufactured with rubber hubs in them which will absorb quite a bit of shock. That wasn't the case with the old shear hubs, as well as solid-mounted hubs.

Yes the hotshot is SS, and the blades are strong and thin; has a little cupping on the trailing edges so you can run a little higher-and a little faster, with no loss in low end if the correct pitch is chosen. Also if you order it at a Yamaha dealer (if they don't have one in stock), Turbo (a division of Yamaha) will send it to the dealer with free shipping, but if you order it from a non-yamaha dealer, you're gonna get hit with shipping. Might save you a few dollars.

You "should" see max RPM with a slight shop. Calm water should be 50-100 RPM lower if it's set up properly. Also, you're going to see MAX rpm on a "cold" engine, one that's been sitting a few hours so that the air under the cowling is cool. Once it heat soaks, the temp sensor on the EFI pulls a degree or two of timing which will slow it down a little-that is normal, and to be expected. Mine will see 30 mph right off the trailer. After a 10 minute run to the "hole", limiting out, then heading back, I'm down to 29 or a little less and about 100 RPM difference. Remove the cowl and it'll run against the limiter at 30 again, but chance getting some spray up in it's nostril-which isn't good for the engine.

I noticed the same thing with losing rpms after it warmed up. The one I just bought doesn't seem to drop as much as the 2020 modelI had but maybe it's the same. It was about 150 rpm. I'll pay more attention next time out.

 

[LDUBS]

I know this is an old post. I’m the op so I figured I could revive it if I had new info to post. I thought it might help someone if they were trying to figure out their prop selection.
We have been running the boat mainly with the factory Yamaha 10 ½ pitch aium prop on it. At times I’d put the Yamaha 9 pitch on. These props still left me feeling short of where I’d really like to be and wanting better performance. Then come’s along the covid checks. Even though I contracted covid we were blessed with limited impact from it. We spread the love around by donating some of the c money and yes I also decided I wanted to try another prop.
I reread some old post I had book marked, researched some more, made some phone calls etc. Learned about prop slip in the process also. I was getting like 19.68 % slip with the Yamaha 10 ½ p. I felt that was way to much and was a deciding factor to try another prop. I was going to try a Piranha composite prop but ended up ordering a SS Power Tech SRA3 in 9 pitch. Power Tech got their start with small engine props and there are a few threads on the skiff forums mentioning these props. Thought it was a no brainer. I had called and talked to them a couple of times. Was told the old rule that going from alum to stainless you drop one pitch to stay at the same rpms. I needed to gain about 400 rpms on the alum 10 ½ pitch. The techs said the SRA3 in 9 pitch should put me where I wanted to be.
It was a long four weeks waiting for the new prop. I was giddy when it finally arrived. Opened up the box to a sweet looking polished SS prop. Couldn’t stand it and went out and installed it. The weather cooperated that weekend so we went to the lake. Launched the boat, let the motor warm up while getting things ready, put it in gear to leave and oh my. There was more prop chatter than with any of the alum props I’ve tried. These new 25 HP fuel injected Yamahas are known for low rpm shake but it was a bit too much for me. Drove around some but the performance was not what I wanted. It had a hard time hooking up when going straight let alone in a turn. When I could get it settled in at full throttle it would only turn 5660 rpms at 21 mph. That’s like 9.45 % slip which is good on paper but just not the rpms and mph I wanted. I was thinking I’d gain at least a couple hundred rpms and maybe a mph or two not lose them. Knowing the performance I wanted wasn’t there we went back to the ramp to switch out the new prop. Didn’t want to take the chance of damaging it so I can sell or return it. Anybody need a SS prop.
We are always beaching the boat to take a break from fishing and to let the dog run. A few times we’ve gotten into some shallow water. As a result the outer edges of the 10 ½ alum prop got worn down slightly from hitting mud and small rocks. It didn’t look like new anymore. So while waiting for the new prop to come in I decided to give it a little tune up. I sanded the leading edges down to a taper some and removed any casting boogers. When I took the new SS prop off at the ramp I put this one back on. Same day, same load and conditions it hit 5920 rpms at 22.7 mph which is 19.79 slip. More rpms but more slip. Don’t know if I want to go thru the trouble of trying the piranha prop now.

Just simple curiosity, what boat you running the Yamaha 25?

 

[turbotodd]

Powertech SRA is an outdated, high rake, bow lifting prop that takes a lot of power to turn it. On a 2 stroke they worked just ok, acceptable. They were fast top end but getting out of the hole was pretty sorry in my opinion. On a 4 stroke, not so much. There are better options now. Powertech has a lot of options and unfortunately they tend to favor the SRA3's even on the 25 4 stroke outboards, and that's just not the right prop for them in my experience. Maybe if you can find a Yamaha black steel prop for the 25hp, try that. Those were semi-cleaver style, always worked pretty good. Some shops were able to make a few tweaks to them and get even more out of em.

 

[sonny.barile]

Without power trim you will never have optimum speed, rpm, and trim for all scenarios.

Most boats achieve WOT optimum rpm by using the power trim while under way. If you left the trim at that setting and stopped the boat, then tried to get back up without trimming down, you would never get on plane. Having one trim position (no power trim) and still achieving plane, means you are not dialed in for optimum rpm at WOT.
Moral of the story…….the 10-1/2 P prop is doing pretty good in the absence of power trim. Leave it alone…….having the second prop of lower pitch is ideal for when you have a planned heavy load.

Go enjoy your boat……