new prop

[SmokyMtnGrady]

So, many years ago I had a power tec OS4. It gave my boat better stern lift, hole shot, mid range cruising performance,better following sea performance and reverse at the dock. I repowered in 17 and had it on it. Then some thiefs decided they wanted the prop and took the motor too. My new motor to replace my new stolen prop came in with a 3 blade SSII prop. I never replaced it. I ordered a new OS4 a few weeks ago from Prop Gods and will have it for my upcoming trip. Excited to get a 4 blade back on the stern.

 

[patrick16]

What's the benefit to a 4 blade over a 3 blade?

 

[efx]

I have been impressed with power tech. Enertias are my favorite, but power tech is a very close second. Good luck with it. Get the wot rpms in range.

 

[SkunkBoat]

What's the benefit to a 4 blade over a 3 blade?

Generally, 4 blades "grip" the water better..meaning there is less "slip". They are often used on heavy boats and offshore boats that encounter ugly conditions.
They tend to raise the stern compared to 3 blades. They help keep a heavy boat on plane at lower seeds.

They are not the best choice for every boat. Not even for most boats. There is a trade-off. Less top end speed, slower acceleration, and lower mpg

 

[SmokyMtnGrady]

What's the benefit to a 4 blade over a 3 blade?

I found on the 228 I get better hole shot and on plane faster. I could stay on plane as low as 21. I got on average 10% better fuel economy at cruise . I got better following sea performance. meaning you could feel the bite or grip especially in bigger swells . I found I got better turning performance when doing water sports it didn't ventilate or blow out in a tight turn. I also like slow speeds docking handeling better. You lose though 1 or 2 mph at the top end . the extra blade is more drag .

 

[SmokyMtnGrady]

Generally, 4 blades "grip" the water better..meaning there is less "slip". They are often used on heavy boats and offshore boats that encounter ugly conditions.
They tend to raise the stern compared to 3 blades. They help keep a heavy boat on plane at lower seeds.

They are not the best choice for every boat. Not even for most boats. There is a trade-off. Less top end speed, slower acceleration, and lower mpg

I have to disagree Skunk My cruise rpm went down and fuel economy improved by 10%. I also noticed better not worse acceleration. in many ways 4 blade props are better except top end due to the drag factor. again, this was on a Yamaha F250 3.3 liter motor and a 228. I am excited to see what the 4.2 does with it.

my boat would get 3.1 mpg and with the 4 blade it would be 3.2 to 3.3 based on Yamaha fuel management system. That's real world for cruising RPM on the boat ...which was around 3600 RPM doing 27 -28.

In the ocean I rarely get sea states where I can run it at WOT. I do get plenty of time in the 3500 to 4500 range and that's where 4 blades shine . On the lake I will run it at WOT because it helps the motor blow carbon out and such. I am headed to the Keys next week and I will report back on the performance.

 

[SkunkBoat]

point is, it depends on the boat/motor and the size of 3 blade /4 blade props you are comparing, the conditions you operate in, and your expectations for cruise speed and top end.

I have 4 blades on my Zukes.
I get better acceleration also because the 3 blades(of a particular size that maxed the rpm) slipped and could not get the boat out of its own way. The same 3 blades that sucked out of the hole were faster and had .1 mpg better at cruise (in a calm river). In the offshore conditions I run in I'm sure I am doing better with the overall mpg than if I had the 3 blades.
When I went to bigger 3 blades, they didn't slip but I could not get near the rpm I needed.
and yes, the 4 blades are better in a tight turn.

So, when they help you they really help you but...

In general...
On smaller, lighter boats in bays and lakes there is probably a better 3 blade option than a 4 blade. There is a reason why 3 blades dominate the market and are the first thing the dealer tries.

Wouldn't it be great if we could just keep trying different props for free all season until we found the exact match to our boats

 

[trapper]

Hi guys, Is there a four blade prop for the Yamaha outboards that have the SDS feature (eliminate clunking on shifting) I have the F200 xb on a 208 I would have to arrive at the right pitch on order, as there is very limited chances here to try out props. I realize one needs to know boat load, present WOT and the sea conditions one boats in etc.

 

[DennisG01]

OK, the REAL question is... can you KEEP it that pretty looking?

FYI, McGuard (and probably others) makes a prop lock - it replaces the prop nut

 

[Ryhlick]

Smokey,
What pitch prop did you get?
Thanks

 

[SmokyMtnGrady]

I have to disagree Skunk My cruise rpm went down and fuel economy improved by 10%. I also noticed better not worse acceleration. in many ways 4 blade props are better except top end due to the drag factor. again, this was on a Yamaha F250 3.3 liter motor and a 228. I am excited to see what the 4.2 does with it.

my boat would get 3.1 mpg and with the 4 blade it would be 3.2 to 3.3 based on Yamaha fuel management system. That's real world for cruising RPM on the boat ...which was around 3600 RPM doing 27 -28.

In the ocean I rarely get sea states where I can run it at WOT. I do get plenty of time in the 3500 to 4500 range and that's where 4 blades shine . On the lake I will run it at WOT because it helps the motor blow carbon out and such. I am headed to the Keys next week and I will report back on the performance.

Smokey,
What pitch prop did you get?
Thanks

I will hit a couple answers here.

Power Tech makes a knock off SDS hub called Cushion Lock.. It should not clunk. KY runs one now and he can verify .

So,skunk is right . I think if you swap the exact same size prop from a 3 to 4 you get those performance drop offs.

To answer what pitch , I called Ken at Prop Gods, highly suggest y'all do the same if you are wanting to reprop. The OS4 comes in a standard 15.25 diameter and Ken says with the gearing on the 4.2 liter F250 F300 it kind of falls on the line between 15 and 16 pitch. I got a 15.25 by 16 pitch. My SDS Saltwater series ii prop is 15.5 by 17 inch pitch. Ken says when adding ears drop down at least 1 full inch of pitch to get optimum RPM and performance. So if I stayed at 17 pitch my motor would be over propped and perform like a dog.

 

[Holokai]

Call Ken at Prop Gods in Florida or call PowerTech directly. Either will help guide with the sizing based on your engine, hull, current prop specs, and intended use.

Prop Gods - (941) 735-5808
PowerTech - (800) 736-7767

Their input will get you in the ballpark for the appropriate WOT RPM range. Ultimately you’ll have to run the boat to see what the real-world performance will be.

Do not aim to match dealer performance data; it is usually worthless since it’s under ideal conditions with a lightly loaded vessel.

 

[Ryhlick]

I will hit a couple answers here.

Power Tech makes a knock off SDS hub called Cushion Lock.. It should not clunk. KY runs one now and he can verify .

So,skunk is right . I think if you swap the exact same size prop from a 3 to 4 you get those performance drop offs.

To answer what pitch , I called Ken at Prop Gods, highly suggest y'all do the same if you are wanting to reprop. The OS4 comes in a standard 15.25 diameter and Ken says with the gearing on the 4.2 liter F250 F300 it kind of falls on the line between 15 and 16 pitch. I got a 15.25 by 16 pitch. My SDS Saltwater series ii prop is 15.5 by 17 inch pitch. Ken says when adding ears drop down at least 1 full inch of pitch to get optimum RPM and performance. So if I stayed at 17 pitch my motor would be over propped and perform like a dog.

Smoky,
Thanks for the detailed response, I appreciate it. I was curios which one you were running, as I am running the same one you are. I have the 16 pitch on m yamaha ox66 225 and it is perfect. Thanks again and enjoy the 4 blade performance.
Cheers, Brad

 

[Ky Grady]

I'm running the same as Smoky and Ryhlick on my F225 and it has been a great prop. I spoke with Ken, and will be keeping this prop to run on my new 4.2 F250 when I repower this fall/winter since Yamaha is dragging their feet. There is no clunk or prop chatter with the PowerTech either.

 

[Hookup1]

Below is a re-post of my experience switching props. I couldn't be happier. Game changing performance with no downside for me. It's more important to let the engine breath and not bog down thru the range you use your boat. Tuning your boat for top end speed that you almost never use is a testosterone thing. You may find out that you don't loose any top end speed.

I have been running a 268 Islander with twin Yamaha f-150's with 17 x 14 1/4 3-blade Yamaha Reliance stainless.

Generally the boat is a 10 knot or 20 knot boat with no in-between. I want to improve my low end performance so I can plane at lower speed. I have plenty of top end and can only use it on the best of days.

I spoke to Ken at propgods.com and he recommended swap for 15 x 14 4-blade. Thinks my low speed performance would significantly improve and maybe even my top end speed.

Propgods.com recommended these…

https://propgods.com/shop/ols/products/ptz4 (on order)
or these
https://propgods.com/shop/ols/products/ptz3 (similar to Yamaha Reliance)

So I've had my chance to test these props in the Florida Keys this winter. For my 1997 268 Islander w/twin F150's they are absolutely perfect. Dropped 2" of pitch, 1/4" of diameter and changed to a different style prop (vs Yamaha Reliance). Significant - unbelievable improvement in low and mid range performance. Boat will plow and plane at lower speeds that could not be done before. Top end unaffected. In rough seas motors don't bog down and "grip" better to keep boat from falling off. Highly recommend.

A lot of boaters think dropping pitch will slow the boat down. Not always true. If over propped and "slipping" its too much load on the engines. Prop correctly and increase efficiency.

I have been planning to write them down but its been so windy and rough. I'll do it this week. For me though it's more about how the boat feels in different sea conditions.

For example running in with a following sea was always a problem. You push the throttles up to a speed to match the waves behind you. Run along for a short while and the boat gets some air under it and runs away at 20 knots. It then crashes into a wave in front of the boat, boggs down the engines and you are back at 10 knots. Much different now. You can pick a speed either plowing or planning and the engines will hold RPM's. It's a easier ride instead of getting slammed around.

Also I ran offshore in a head sea. Easier to dial in a speed and the level of abuse you want to take. Holds RPM's much better.

I have run the motors up a few times when conditions permitted. The cruise and top end are still there. I'll get numbers up this week.

So here are the raw numbers from a Florida Bay run by Channel 5 East to West and reversed. Blowing 20 knots ESE. 150 gallons of fuel and 2 people on board. 15 gallon bait well with water on transom step. Lots of gear on boat.

Higher end performance is right in there with the old props. Low end performance much better. You could not plane at 3,400 RPM's. 3,900 RPM's and is was problematic.

 

[SmokyMtnGrady]

I'm running the same as Smoky and Ryhlick on my F225 and it has been a great prop. I spoke with Ken, and will be keeping this prop to run on my new 4.2 F250 when I repower this fall/winter since Yamaha is dragging their feet. There is no clunk or prop chatter with the PowerTech either.

Ok, since nobody is going to ask. How does the power tech prop do at making coleslaw or chipping up wood? Asking for a friend.

Below is a re-post of my experience switching props. I couldn't be happier. Game changing performance with no downside for me. It's more important to let the engine breath and not bog down thru the range you use your boat. Tuning your boat for top end speed that you almost never use is a testosterone thing. You may find out that you don't loose any top end speed.

I have been running a 268 Islander with twin Yamaha f-150's with 17 x 14 1/4 3-blade Yamaha Reliance stainless.

Generally the boat is a 10 knot or 20 knot boat with no in-between. I want to improve my low end performance so I can plane at lower speed. I have plenty of top end and can only use it on the best of days.

I spoke to Ken at propgods.com and he recommended swap for 15 x 14 4-blade. Thinks my low speed performance would significantly improve and maybe even my top end speed.

Propgods.com recommended these…

https://propgods.com/shop/ols/products/ptz4 (on order)
or these
https://propgods.com/shop/ols/products/ptz3 (similar to Yamaha Reliance)

So I've had my chance to test these props in the Florida Keys this winter. For my 1997 268 Islander w/twin F150's they are absolutely perfect. Dropped 2" of pitch, 1/4" of diameter and changed to a different style prop (vs Yamaha Reliance). Significant - unbelievable improvement in low and mid range performance. Boat will plow and plane at lower speeds that could not be done before. Top end unaffected. In rough seas motors don't bog down and "grip" better to keep boat from falling off. Highly recommend.

A lot of boaters think dropping pitch will slow the boat down. Not always true. If over propped and "slipping" its too much load on the engines. Prop correctly and increase efficiency.

I have been planning to write them down but its been so windy and rough. I'll do it this week. For me though it's more about how the boat feels in different sea conditions.

For example running in with a following sea was always a problem. You push the throttles up to a speed to match the waves behind you. Run along for a short while and the boat gets some air under it and runs away at 20 knots. It then crashes into a wave in front of the boat, boggs down the engines and you are back at 10 knots. Much different now. You can pick a speed either plowing or planning and the engines will hold RPM's. It's a easier ride instead of getting slammed around.

Also I ran offshore in a head sea. Easier to dial in a speed and the level of abuse you want to take. Holds RPM's much better.

I have run the motors up a few times when conditions permitted. The cruise and top end are still there. I'll get numbers up this week.

So here are the raw numbers from a Florida Bay run by Channel 5 East to West and reversed. Blowing 20 knots ESE. 150 gallons of fuel and 2 people on board. 15 gallon bait well with water on transom step. Lots of gear on boat.

Higher end performance is right in there with the old props. Low end performance much better. You could not plane at 3,400 RPM's. 3,900 RPM's and is was problematic.

I really think most Grady's powered by Yamaha in particular would benefit from 4 blade props. They are heavy and the SeaVee hull had its own ride and planing characteristics. Your data is impressive.

This is my second prop from Ken and he ,as far as I can tell on the internet,is spot on in his ability to get the right prop for the boat. He got you dialed in really well.