Like Tree0Likes

Is a 5 blade harder on drives than a 4 blade?

Old 03-08-2007, 09:44 PM
dreamboater's Avatar
Join Date: Apr 2002
Location: Southern Maryland
My Boats: 2000 28 Skater
Posts: 1,234

Originally Posted by JIMKID Motorsports View Post
acually it can be smoother cause you have more blade in the water ask throtle up propellors they will tell you less vibration than 4 blades
I know what you are saying, but I have yet to shake a carrier loose due to running 3 blades. A lot of other guys I boat with that run O/B's run 4 blades due to less vibration though. I would think the newer XR style cases are even less prone to failure due to excess vibration.
dreamboater is offline  
Reply With Quote
Old 03-09-2007, 09:06 AM
Frequency's Avatar
Join Date: Aug 2001
Location: Peoria, IL & FMB, FL
My Boats: '91 Carbon 70 Cafe, 3370 Pursuit
Posts: 1,008

It depends on if your concern is failures due to reentry or blade induced torsional vibration.

Reentry failure is related to blade area. In general, the more blades you have the greater the total blade surface area. It's possible that a four bladed prop would be worse than a five bladed prop if it's blade area is greater.

With regard to torsional vibration it is a good generalization to assume that vibration levels decrease with the number of blades. Higher frequencies are more easily damped and there is quite a bit of damping in a marine propulsion system. You have to remember that driveline vibration is a function of the whole system. Outdrive type, drive ratio and coupler type all come in to play. In some cases fewer blades are better.

Frequency is offline  
Reply With Quote
Old 03-09-2007, 10:12 AM
Join Date: Dec 2006
Location: Tucson, AZ
My Boats: 40 Skater
Posts: 495

Originally Posted by johnnyboatman View Post
40 how much?
I'll take 350ea. They came on my Spectre but were a little tall. I purchased some 32's and when I traded the boat in I kept the 34's. They are perfect.
40FlatDeck is offline  
Reply With Quote

Related Topics
Thread Starter
Last Post
05-15-2008 08:14 PM
382 newbie
Prop Talk
05-14-2007 04:57 PM
Prop Talk
05-14-2006 09:21 AM
Prop Talk
07-04-2005 03:34 AM

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 On
Pingbacks are On
Refbacks are On

All times are GMT -5. The time now is 09:47 PM.

Copyright 2011 OffShoreOnly. All rights reserved.