Props to address Cutwater performance

Jcat2010 said:
Good to see the power techs are working out great for other models. One note about the "fear" of changing a prop while in the water......I use a 4 ft diameter inflatable kiddie pool, with three sidewalk tubes. Slide it up under the raised lower unit, anything that falls falls into the bottom. I even use it to periodically check the shaft seal for leakage. If only I could figure out how to change the lower unit oil using it.
Click to expand...
I can't figure out the lower unit either. The only idea I had was borrowing a neighbor's hydraulic lift. If there was one that was the right size.
 
The only "practical" option that I've used on smaller outboards is to hoist the engine up with a lift mounted on deck, but out umbilical isn't long enough to clear the water; and even with a 115 HP that was not the easiest, but it did work. I have seen boats where the outboards are on a jack plate, and the lower unit, vertical, can be out of the water, but that's not my tugs either

I'm not giving up yet, there's a way but it will never allow the water pump replacement, that's gotta be a haul out.
 
A buddy of mine, who is a jet mechanic, did my impellers once in a way that I would never recommend. We backed the boat into shallow water and he pulled them off to do the work. The lower units on 300s should not be carried through moving waters by anyone who is not a champion weight lifter. He did it since another guy suggested it and his manliness did the rest, but, pulled a muscle doing so.
 
Interesting to see the drop in pitch actually lower the GPH burn and raise the MPH.
 
I'm told that the extension tubes provide some level of stern lift so I was able to go with a slightly smaller prop which delivered slightly higher RPM at WOT.
 
A few folks have had their exhaust extension fall off. PowerTech has replaced them as a courtesy, at no charge. However, changes are coming...

Channel Surfing Edition Prop - Changes are coming...
 
Just wanted to add my experience with prop change. I have a 2022 Cutwater C32 C with twin F300 Yamaha’s. I got a recommendation from Ken at Propgods and upgraded to Power Tech 4 blade 16P.

I’ve only run the new props for a little over a month but have seen measurable improvements in cruise rpm, speed, burn and prop slip.

Best rpm is 4400 down from 4600 and the riding attitude improved with better stern lift. I’ve initially focused on the cruising rpm range with roughly similar conditions and 200g of fuel and no tabs.

New Props Analysis

Original Stock 3 Blade:
4400 30.2mph 31.6gph 0.96mpg Slip 33.23%

New Power Tech 4 Blade:
4400 31.2mph 29.6gph 1.06mpg Slip 18.09%

Difference:
+1.0mph +3.3%
-2.0gph +6.3%
+0.1mpg 10.4%

New cruising rpm averages:
4200 27.5mph 27.1gph 1.01mpg Slip 24.36%
4400 31.2mph 29.6gph 1.06mpg Slip 18.09%
4600 32.4mph 34.6gph 0.936mpg Slip 18.63%

One issue I noticed is the fuel burn difference between the standard & counter rotating motors. The counter burns @ 2.5g/8% more fuel. Not sure how normal this is but I have experienced a higher burn in a HydraSport 33 with trip ETec 250s. The one counter burned more but I need to find my old data to compare

Tom
 
TomM7986 said:
Just wanted to add my experience with prop change. I have a 2022 Cutwater C32 C with twin F300 Yamaha’s. I got a recommendation from Ken at Propgods and upgraded to Power Tech 4 blade 16P.

I’ve only run the new props for a little over a month but have seen measurable improvements in cruise rpm, speed, burn and prop slip.

Best rpm is 4400 down from 4600 and the riding attitude improved with better stern lift. I’ve initially focused on the cruising rpm range with roughly similar conditions and 200g of fuel and no tabs.

New Props Analysis

Original Stock 3 Blade:
4400 30.2mph 31.6gph 0.96mpg Slip 33.23%

New Power Tech 4 Blade:
4400 31.2mph 29.6gph 1.06mpg Slip 18.09%

Difference:
+1.0mph +3.3%
-2.0gph +6.3%
+0.1mpg 10.4%

New cruising rpm averages:
4200 27.5mph 27.1gph 1.01mpg Slip 24.36%
4400 31.2mph 29.6gph 1.06mpg Slip 18.09%
4600 32.4mph 34.6gph 0.936mpg Slip 18.63%

One issue I noticed is the fuel burn difference between the standard & counter rotating motors. The counter burns @ 2.5g/8% more fuel. Not sure how normal this is but I have experienced a higher burn in a HydraSport 33 with trip ETec 250s. The one counter burned more but I need to find my old data to compare

Tom
Click to expand...
I'm presuming these are the OFS 4s vs. the SCE 4s that I tried. The 4 blades did little to improve performance for me and, after trying several different prop sets, I ended up with PowerTech OFS: 5 blade 16 inch with EXT. As mentioned earlier in the thread, I'm thrilled with the results and feel the change qualifies as 'it's like a new boat'.
 
Would the OSF5 with 16 inch pitch and extension be the same (or similar) performance gains for a c-32 Coupe? (versus the c-302 Rocky tested)
I am getting a brand new c-32 Coupe next week and I was wondering how long to wait before I switch the props to make the gains indicated in this thread. I am near Seattle so I won't do much traveling until next spring (2026).
 
Hopefully, someone tried it with a C32 and will post. I'd suggest contacting PowerTech since they should know and they will likely be willing to swap the propeller should you not get the desired results or close to them.
 
Thanks to the work Rocky Lou did on prop testing for the C302. We have a pair of new OFS5 16 pitch with ext tube on our Solara S310 SB!
We have 200 hours and about 2400 miles on our 310 with the factory 3 blade SS2 19 pitch prop. So you know we have run in all kinds of conditions and know how the boat handles with the 3 blade. Also lots of fuel data. She was thirsty with the 3 blades.

Boat weight
2 people, normal cruising supplies, full water , full fuel. No fishing or shrimping gear.

Attached is a comparison of what we saw between the 3 and 5 blade props. We have found no negative to the 5 blade. Only lost 1 mph on WOT 5700 rpm too but we only run wide open for short times to burn out the carbon.

Besides the economy improvements which are pretty nice, about 20% at cruise and higher gains in the mid range. We can now run from 20-32 at lower rpm and huge economy gains at those speeds and keep the boat on plane. Prior to the 5 blade if you ran in those speeds the bow would remain too high to really see things in the water plus the boat just pounded the waves.
With the added stern lift of the 5 blade the ride is quieter, smoother, no noise from hull double step. Auto glide trim tabs seem to function better. There is no hunting from side to side. Prior to the 5 blades the auto tabs would cause the boat to list side to side at times when above 37 mph. Now is just flat all the time. The hole shot and acceleration is greatly improved. Oh and cornering is amazing too.

Summary.
Our main reason for going to the 5 blades was to make the mid range usable with improved mid economy. Cruising in the 20 to low 30 will be much more enjoyable when the conditions are rough. Less stress on the crew watching debris in the water when compared to running mid to upper 30s like the 3 blade ran best at.
For us the OFS5 16 with ext tube is a huge win!

So far the OFS5 16 pitch and tube works on Rocky Lou’s C302 and our Solara S310 SB with twin 300.
It is likely a match for the C32 with twin 300. Also wondering about how it would do on a C288 with twin 250.
If anyone is near Anacortes and want to try them let me know.
Mike
IMG_6149.jpeg

IMG_6263.jpeg
 
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TomM7986 said:
Just wanted to add my experience with prop change. I have a 2022 Cutwater C32 C with twin F300 Yamaha’s. I got a recommendation from Ken at Propgods and upgraded to Power Tech 4 blade 16P.

I’ve only run the new props for a little over a month but have seen measurable improvements in cruise rpm, speed, burn and prop slip.

Best rpm is 4400 down from 4600 and the riding attitude improved with better stern lift. I’ve initially focused on the cruising rpm range with roughly similar conditions and 200g of fuel and no tabs.

New Props Analysis

Original Stock 3 Blade:
4400 30.2mph 31.6gph 0.96mpg Slip 33.23%

New Power Tech 4 Blade:
4400 31.2mph 29.6gph 1.06mpg Slip 18.09%

Difference:
+1.0mph +3.3%
-2.0gph +6.3%
+0.1mpg 10.4%

New cruising rpm averages:
4200 27.5mph 27.1gph 1.01mpg Slip 24.36%
4400 31.2mph 29.6gph 1.06mpg Slip 18.09%
4600 32.4mph 34.6gph 0.936mpg Slip 18.63%

One issue I noticed is the fuel burn difference between the standard & counter rotating motors. The counter burns @ 2.5g/8% more fuel. Not sure how normal this is but I have experienced a higher burn in a HydraSport 33 with trip ETec 250s. The one counter burned more but I need to find my old data to compare

Tom
Click to expand...
Tom
I wonder how much more improvement you would gain by having the ext tube added to your props. You can send them back to power tech. They will modify them and add a welded on stainless tube. The tube adds more lift.
 
Mike and Sarah said:
Thanks to the work Rocky Lou did on prop testing for the C302. We have a pair of new OFS5 16 pitch with ext tube on our Solara S310 SB!
We have 200 hours and about 2400 miles on our 310 with the factory 3 blade SS2 19 pitch prop. So you know we have run in all kinds of conditions and know how the boat handles with the 3 blade. Also lots of fuel data. She was thirsty with the 3 blades.

Boat weight
2 people, normal cruising supplies, full water , full fuel. No fishing or shrimping gear.

Attached is a comparison of what we saw between the 3 and 5 blade props. We have found no negative to the 5 blade. Only lost 1 mph on WOT 5700 rpm too but we only run wide open for short times to burn out the carbon.

Besides the economy improvements which are pretty nice, about 20% at cruise and higher gains in the mid range. We can now run from 20-32 at lower rpm and huge economy gains at those speeds and keep the boat on plane. Prior to the 5 blade if you ran in those speeds the bow would remain too high to really see things in the water plus the boat just pounded the waves.
With the added stern lift of the 5 blade the ride is quieter, smoother, no noise from hull double step. Auto glide trim tabs seem to function better. There is no hunting from side to side. Prior to the 5 blades the auto tabs would cause the boat to list side to side at times when above 37 mph. Now is just flat all the time. The hole shot and acceleration is greatly improved. Oh and cornering is amazing too.

Summary.
Our main reason for going to the 5 blades was to make the mid range usable with improved mid economy. Cruising in the 20 to low 30 will be much more enjoyable when the conditions are rough. Less stress on the crew watching debris in the water when compared to running mid to upper 30s like the 3 blade ran best at.
For us the OFS5 16 with ext tube is a huge win!

So far the OFS5 16 pitch and tube works on Rocky Lou’s C302 and our Solara S310 SB with twin 300.
It is likely a match for the C32 with twin 300. Also wondering about how it would do on a C288 with twin 250.
If anyone is near Anacortes and want to try them let me know.
Mike
View attachment 26784

View attachment 26783
Click to expand...
Great to see these results on a Solara! I suggested to PowerTech leadership that they market their products using the slogan, 'it's like having a new boat'...since that truly was the case for me. A buddy of mine, a marine engineer, sold his C32 due to the performance issues.
 
alansails said:
Not trying to hijack the thread but we have the diesel fixed prop, any thought on efficiency, speed etc?
Click to expand...
I haven't seen anyone raising concerns on inboard performance. My thoughts are the Cutwater 30 was properly designed with a performant hull, whereas, the repower with outboards produced a non-performant hull due to stern drag that is even worse on LE (generator) Models. PowerTech offers: https://www.ptprop.com/inboard-nibral-propellers.html and you could speak to Jared and see what his thoughts are on performance improvement. Everyone I've talked to has had a positive experience with PowerTech. They clearly are not perfect and hard to communicate with, but, they work with customers and are determined to get it right.
 
PowerTech has not released the extension tubes (Channel Surfing edition) prop's to the prop shops/dealers.
The exhaust tubes are only available directly from PowerTech. They take a normal OFS or SCE prop, machine it, and weld on the exhaust tube.
Contact jared at ptprop dot com as he handles all these modifications directly.
If you have trouble getting ahold of him, send me a note and I'll give you his personal cell number.

The exhaust tube offers considerable improvement for the mid-range, providing stern lift and improved fuel efficiency. (3,000-4,000 RPM).

On my OFS4-15, this was the difference I saw with and without the exhaust tube. (Single F300, R27).
This was the 3" extension. The 4" extension that is shipping today is a little better.
OFS4 Comparison.png

Performance Perfected with PowerTech!
 
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Jcat2010 said:
Good to see the power techs are working out great for other models. One note about the "fear" of changing a prop while in the water......I use a 4 ft diameter inflatable kiddie pool, with three sidewalk tubes. Slide it up under the raised lower unit, anything that falls falls into the bottom. I even use it to periodically check the shaft seal for leakage. If only I could figure out how to change the lower unit oil using it.
Click to expand...

I've changed many prop's while the boat is in the water. I back the boat up to the dock in a finger slip. I just take my time. The cotter pin I run a piece of micro-cord though it as it's easy to drop. This is LemonDrop (2019 R27-OB).

IMG_6336.jpeg

IMG_6330.jpeg
 
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Mike and Sarah said:
So far the OFS5 16 pitch and tube works on Rocky Lou’s C302 and our Solara S310 SB with twin 300.
It is likely a match for the C32 with twin 300. Also wondering about how it would do on a C288 with twin 250.
Click to expand...

I know of a set of OFS5-16 CS Editions being ordered for a C-288. I suspect they'll see the same results you did.
I also know of a set of OFS5-15 CS Editions being ordered for a Jeanneau 895 (Twin F250's).
 
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When changing out the prop on my C24 I simply slide a pool mat under the prop. It catches anything that falls on it.
Ken
Sunny Daze
 
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