Need. More. Speed.

[QC]

Re: Need. More. Speed.

Since you are at the high end of the WOT range, I also think it could be faster. If you were lightly loaded, and you spend much time with watersports I would stick with what you have. If budget was not an issue I'd try it out in a heartbeat.

 

[Circles47]

Re: Need. More. Speed.

Since you are at the high end of the WOT range, I also think it could be faster. If you were lightly loaded, and you spend much time with watersports I would stick with what you have. If budget was not an issue I'd try it out in a heartbeat.

Oh QC, don't do this to me! I'm already dangerously close to ordering another one! So.......if you were to buy a new 19 S/S prop, what brand would you get? This Turning Point prop I got is exceeding my expectations, but perhaps another brand would have done as well or better.

 

[QC]

Re: Need. More. Speed.

I'll spend your money all day long. If your results are accurate I would go exactly the same.

 

[pokman]

Re: Need. More. Speed.

DO you have a local prop shop that you could try out a used 19p-or put a add on craigslist that your looking for a 19p and would like to try it. Agree with QC on the rpms, I bet you would still be at around 5100 rpms if you go to the 19.

 

[Circles47]

Re: Need. More. Speed.

To quote the late Admiral Farragut: "Damn the torpedoes, full speed ahead!"

I ordered a 19" S/S prop this morning, same as my previous 17". I can hear it already......(wife)... Honey, what did UPS bring today? (Me)...Ummm...UPS? They brought something??? Must be something for the business......Say Hon, would you like me to take you out for supper tonight??

 

[steelespike]

Re: Need. More. Speed.

Generally a correct ss prop will improve performance across the board. I usually quote "improvement from a few tenths to a few mph"
I think part of the very pleasant improvement was the under performing al prop.
And I think in this case at least part of the improvement could be had with the right al prop.
Another advantage with ss props is they hold up better in a soft contact in sand or mud
of course they do cost more to fix when it comes time.

 

[QC]

Re: Need. More. Speed.

I think part of the very pleasant improvement was the under performing al prop.

I agree with this. The only way we could really draw any solid conclusions regarding Al to SS on any given hull would have to include a wide variety of props and all in good condition.

 

[pokman]

Re: Need. More. Speed.

circles,

PM'd you

 

[Circles47]

Re: Need. More. Speed.

Well, got my new 19 pitch prop, and headed to the lake today. The experience was both good and bad.

Water conditions were rougher than last time, some chop and a 15-20 mph wind.


Pokman, you were dead on.....WOT RPM's only dropped from 5200 to 5100. That was a pleasant surprise. I figured with increasing pitch 2 inches, I'd drop a bit less than that.

Hole shot a little less than it was before, but not too noticeable. We'll have to see how it performs under watersport load.
Still comes up on plane very fast, I'd say about equal or close to the 17 prop.
There was an increase in top-end, although not as much as from the 17 aluminum to the 17 stainless.
As near as I could tell, I picked up about 2 mph. I had to calculate an average from running with the wind, and then against it. I'm going to guess it tops out at 41.5-42 mph, which is what I hoped to achieve originally.

In calculating propeller slip, it looks like I'm still under 10%.

I drove home wondering what a 21 in prop would do! But, I think I'll stop here. I've got a feeling I'd really notice a difference with a 21 in my hole shot decrease. This was all good experience.

Now for the bad. In the midst of my lake trial, my power trim stopped working. Finally had to loosen the cylinder pressure to be able to tilt the motor and get the boat out of the lake. This could only be achieved by wading into chest high water fully clothed. Now I got to figure out if it's a fuse or solenoid, or what........

 

[pokman]

Re: Need. More. Speed.

Circles,

Good gain for the 19p. 42 mph is good for that boat/motor. I too think a 21p would hurt your holeshot and your rpms would get under 5k and you don't want to lug the motor that much I would suspect. Sucks about your trim hopefully it's a cheap fix. PM'd you

 

[sasada]

Re: Need. More. Speed.

Well, got my new 19 pitch prop, and headed to the lake today. The experience was both good and bad.

Water conditions were rougher than last time, some chop and a 15-20 mph wind.


Pokman, you were dead on.....WOT RPM's only dropped from 5200 to 5100. That was a pleasant surprise. I figured with increasing pitch 2 inches, I'd drop a bit less than that.

Hole shot a little less than it was before, but not too noticeable. We'll have to see how it performs under watersport load.
Still comes up on plane very fast, I'd say about equal or close to the 17 prop.
There was an increase in top-end, although not as much as from the 17 aluminum to the 17 stainless.
As near as I could tell, I picked up about 2 mph. I had to calculate an average from running with the wind, and then against it. I'm going to guess it tops out at 41.5-42 mph, which is what I hoped to achieve originally.

In calculating propeller slip, it looks like I'm still under 10%.

I drove home wondering what a 21 in prop would do! But, I think I'll stop here. I've got a feeling I'd really notice a difference with a 21 in my hole shot decrease. This was all good experience.

Now for the bad. In the midst of my lake trial, my power trim stopped working. Finally had to loosen the cylinder pressure to be able to tilt the motor and get the boat out of the lake. This could only be achieved by wading into chest high water fully clothed. Now I got to figure out if it's a fuse or solenoid, or what........

Wow folks, Excellent thread! I obsessed about my new prop purchase for a boat of mine as well. Great info...take notice all!!!!....He posted his results! Thank you!

 

[Circles47]

Re: Need. More. Speed.

I agree sasada about the need to post results. Before I began this thread, I spent considerable time reading other threads, trying to make an educated prop choice. Too many of the threads stop with the new prop purchase, and you never know if they were satisfied with their choice or not.

 

[sasada]

Re: Need. More. Speed.

I agree sasada about the need to post results. Before I began this thread, I spent considerable time reading other threads, trying to make an educated prop choice. Too many of the threads stop with the new prop purchase, and you never know if they were satisfied with their choice or not.

Word! Same thing I have run into with an issue or two. Here is/was my pleasure boat prop results... http://forums.iboats.com/showthread.php?t=540347

 

[Tail_Gunner]

Re: Need. More. Speed.

Here is a ideal take a pic of your engine and leg with the engine trimmed netural...that is...the leg is running vertical straight up and down to your transom..Now what is needed is to see see where your cavitation plate is realtionship to the keel..Aka is the cav plate below the bottom of the boat or above it...measure it in inches....

 

[Circles47]

Re: Need. More. Speed.

Here is a ideal take a pic of your engine and leg with the engine trimmed netural...that is...the leg is running vertical straight up and down to your transom..Now what is needed is to see see where your cavitation plate is realtionship to the keel..Aka is the cav plate below the bottom of the boat or above it...measure it in inches....

Sorry took so long to reply, Tail_Gunner. Even with the jack stand on the trailer fully down, I can't get my motor completely vertical, but close. I held a straight edge on top of the cavitation plate, and it looks like it's about even with the bottom of the keel. I'd say within 1/4".

 

[Tail_Gunner]

Re: Need. More. Speed.

Sorry took so long to reply, Tail_Gunner. Even with the jack stand on the trailer fully down, I can't get my motor completely vertical, but close. I held a straight edge on top of the cavitation plate, and it looks like it's about even with the bottom of the keel. I'd say within 1/4".

That does not sound right drop the tounge on the ground and take a pic..Never had a boat where i could not trim in the leg while on a trailer. This a low rider or something....

 

[Tail_Gunner]

Re: Need. More. Speed.

If your running to deep it would hinder many things

 

[QC]

Re: Need. More. Speed.

I've had two boats where the skeg hit, even with the tongue on the ground. Standard 14" wheels and tries on both

 

[Circles47]

Re: Need. More. Speed.

That does not sound right drop the tounge on the ground and take a pic..Never had a boat where i could not trim in the leg while on a trailer. This a low rider or something....

Had to put trailer tongue on hydraulic floor jack so I could get it back up!

 

[Tail_Gunner]

Re: Need. More. Speed.

Watching you change props along with rpm and slip...the rpm was constant the slip varied a bit and the mph jumped nicely when you added the new props. Even going from alum to ss and then increasing pitch the rpm stayed constant...Your hull is causing this or your engine leg.... thats drag...I cant say for sure but rasing your engine 1" at a time until it blows out should get you some better results.

If that seems unlikely to you remeber even the drag of the 4th blade on a 4 blade prop can casue a 3-5 mh drop when compared to like 3 blade prop. Good luck have fun