Notices
General Propeller Company
 General Propeller

Propeller Sizing and Drivetrain Consulting

Old 06-21-2019, 10:10 PM
  #1  
Member
Marine Advertiser
Thread Starter
 
Join Date: Jun 2019
Location: Bradenton, Florida
Posts: 74
Received 22 Likes on 10 Posts
Lightbulb Propeller Sizing and Drivetrain Consulting

Utilizing the latest software we can analyze your propeller application and determine the correct size, type and material for your vessel.

Shaft sizing calculations to recommend the proper diameter and material for your application.

Contact us today or post any question you have - Get Back On The Water!


Old 11-05-2019, 03:17 AM
  #2  
Junior Member
 
Join Date: Aug 2019
Location: Scranton Pa
Posts: 6
Likes: 0
Received 0 Likes on 0 Posts
Default Need prop choice help...

I have an Ď86 Pennyan 21í fishing boat engine is a 4.3 omc cobra sterndrive. It currently has a 15x17 3 blade prop. I can only achieve 4,000 rpm and 33 mph at WOT. Iíd like to get my rpm in the 4500 range and squeeze 35-38 mph if possible. By changing to a different prop but I can get any info to suggest which direction to go to get both a few more rpmís and a few more mph. Thanks in advance for your help.
Old 11-05-2019, 10:10 AM
  #3  
Member
Marine Advertiser
Thread Starter
 
Join Date: Jun 2019
Location: Bradenton, Florida
Posts: 74
Received 22 Likes on 10 Posts
Default

Hello Oxbow 26

You could go to a Powertech OFS 3 blade 15 1/4 x 15.As you increase rpm there is room to get speed since I believe you have not achieve maximum hp at 4000 rpm on this set up.

Please forward any questions!
Old 11-05-2019, 10:53 AM
  #4  
Junior Member
 
Join Date: Aug 2019
Location: Scranton Pa
Posts: 6
Likes: 0
Received 0 Likes on 0 Posts
Default

Thank you! Thatís the most complete answer Iíve gotten. Iím certain Iím not obtaining peak rpm and several have mentioned a 15 pitch prop but none have said how itíll effect my speed since Iím losing pitch. Thatís where Iím lost... I need RPMs (dropping pitch) but need a few more mph too so itís a catch 22
Old 11-05-2019, 10:57 AM
  #5  
Member
Marine Advertiser
Thread Starter
 
Join Date: Jun 2019
Location: Bradenton, Florida
Posts: 74
Received 22 Likes on 10 Posts
Default

Oxbow 26

There are certain times when going to a lower pitch will reduce speed.
Sometimes we have to opt going to a lesser pitch to increase longevity of the engine and not so much expecting a result of speed increase.
I believe in this particular case you should see a speed gain.
Again, it depends on whether the engine has already hit the maximum horsepower curve or not.

Please forward any questions!
Old 05-05-2020, 03:46 PM
  #6  
Admirals Club Admiral's Club Member
 
Join Date: Sep 2017
Posts: 54
Likes: 0
Received 4 Likes on 3 Posts
Default Mako

I got 87 mako mako with new twin 150 yams 4 stroke. Had problem bad porposing put set stingray fins on them and trim tabs really helped alot. Question is do u think i need 4 blade props and if so what size please?
Old 05-07-2020, 11:43 AM
  #7  
Member
Marine Advertiser
Thread Starter
 
Join Date: Jun 2019
Location: Bradenton, Florida
Posts: 74
Received 22 Likes on 10 Posts
Default

We would be happy to help.What size Mako? Also what props are you currently running? What RPM's are you reaching with your current props at wide open throttle, and what speed are you achieving at WOT?

Thanks

Old 05-07-2020, 12:18 PM
  #8  
Admirals Club Admiral's Club Member
 
Join Date: Sep 2017
Posts: 54
Likes: 0
Received 4 Likes on 3 Posts
Default Props

Its a mako 248 and props now are rel3r17pcl200. Max rpm wot 5100 max speed 38 with twin 2018 150 yams
Old 05-07-2020, 01:05 PM
  #9  
Member
Marine Advertiser
Thread Starter
 
Join Date: Jun 2019
Location: Bradenton, Florida
Posts: 74
Received 22 Likes on 10 Posts
Default

Hello Mako 2482

Based on the current rpm, I would stay with a 3 blade REL Powertech in a 15 pitch. If you still would like a 4 blade option the Powertech PTZ 4 blade in a 15 would be the 4 blade recommended. It is difficult to know if a 4 blade 15 (PTZ) will get to the desired rpm. It might be one case in which if you find your fuel efficiency numbers and speed numbers but the rpm are a bit low (say 5500) you might have to settle...

Please call us if you need pricing or if you have further questions!
Old 02-22-2021, 05:54 PM
  #10  
Junior Member
 
Join Date: Mar 2015
Location: Auroa Indiana
Posts: 11
Likes: 0
Received 1 Like on 1 Post
Default 3 blade verse 4 blade props

May I ask for your expertise, I currently have a Yamaha Reliance series 14 1/4" x 17P 3 blade prop on my Yamaha 175 sho. It is tacking 6300+. Yamaha costumer service said get it down to 6000 - 6100 rpm. I would like to go to a 4 blade prop for better low end and mid range. I have read that if I go to a 4 blade I will lose top end speed, which I really don`t want to if I can avoid it?
My question is can I move up to a 18P four blade or should I stay at a 17P but go to a 4 blade from my current 3 blade?

Also whatever props you recommend do you have them in stock and can I get a price or should I call the number listed?

Thank you Steve
Old 02-23-2021, 05:49 AM
  #11  
Member
Marine Advertiser
Thread Starter
 
Join Date: Jun 2019
Location: Bradenton, Florida
Posts: 74
Received 22 Likes on 10 Posts
Default

Hello Steve
Both props would work. It seems you are at the limiter right now. Either of them would work but to know for sure we need the boat information. Once we determine the hull speed, we could make a better assessment.

You can call our office for different propeller options.

Let me know if any questions!
Old 04-03-2021, 11:11 AM
  #12  
Junior Member
 
Join Date: Jul 2008
Location: NW Florida
Posts: 16
Likes: 0
Received 8 Likes on 3 Posts
Default

Prop recommendation requested:
Boat 25'. 9' beam. 3950 lb hull + 1100 lbs motors + 200 gal fuel= 1200 lbs + 4 fishing @ 200= 800 lbs + gear, refreshments, ice, bait, safety equipment, second helm station, custom T top = 1500 lbs.

Total weight = 8500 lbs worst case loading

Twin Suzuki's DF175AF's...

20 degree dead rise.

seeking quick plane and good cruise

Thanks
Old 04-06-2021, 05:34 AM
  #13  
Member
Marine Advertiser
Thread Starter
 
Join Date: Jun 2019
Location: Bradenton, Florida
Posts: 74
Received 22 Likes on 10 Posts
Default

Hello DF729

Due to the Suzuki's gear ratio I would suggest to try a set of 16 x 19 or 16 x 21 (higher diameter for the 2.50:1 ratio).

We have both pairs in our demo program, so you can try them back to back to see the detailed performance on both sets before picking one.

Feel free to call with any questions!
Old 04-08-2021, 02:35 PM
  #14  
Junior Member
 
Join Date: Jul 2008
Location: NW Florida
Posts: 16
Likes: 0
Received 8 Likes on 3 Posts
Default

Originally Posted by GeneralPropeller View Post
Hello DF729

Due to the Suzuki's gear ratio I would suggest to try a set of 16 x 19 or 16 x 21 (higher diameter for the 2.50:1 ratio).

We have both pairs in our demo program, so you can try them back to back to see the detailed performance on both sets before picking one.

Feel free to call with any questions!

Thank you, will call you when and if I ever get my motors in - coming up on 7 weeks...
Cliff
Old 04-09-2021, 04:18 AM
  #15  
Member
Marine Advertiser
Thread Starter
 
Join Date: Jun 2019
Location: Bradenton, Florida
Posts: 74
Received 22 Likes on 10 Posts
Default

Originally Posted by DF729 View Post
Thank you, will call you when and if I ever get my motors in - coming up on 7 weeks...
Cliff
Sounds good! Yea it's pretty tough to get motors right now. Our number is 941-748-1527, I forgot to put it in the last post.

Thanks again for reaching out!
Old 04-10-2021, 08:09 PM
  #16  
Junior Member
 
Join Date: Apr 2021
Posts: 1
Likes: 0
Received 0 Likes on 0 Posts
Default Yamaha F70 on an Edgewater 158cs

The engine comes stock with an aluminum prop and Iím ready to upgrade to stainless. What do you recommend?
Old 04-12-2021, 09:55 AM
  #17  
Member
Marine Advertiser
Thread Starter
 
Join Date: Jun 2019
Location: Bradenton, Florida
Posts: 74
Received 22 Likes on 10 Posts
Default

Hello Snookfin

We have used in the past the Powertech YM90SCD3R15 also the 13 pitch for the engines rated to 5600 -6300 rated rpm. We usually carry these propellers in stock.

Feel free to call us with any questions!

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.