harmonics vs vibration prop issue - SailNet Community

   Search Sailnet:

 forums  store  


Quick Menu
Forums           
Articles          
Galleries        
Boat Reviews  
Classifieds     
Search SailNet 
Boat Search (new)

Shop the
SailNet Store
Anchor Locker
Boatbuilding & Repair
Charts
Clothing
Electrical
Electronics
Engine
Hatches and Portlights
Interior And Galley
Maintenance
Marine Electronics
Navigation
Other Items
Plumbing and Pumps
Rigging
Safety
Sailing Hardware
Trailer & Watersports
Clearance Items

Advertise Here






Go Back   SailNet Community > General Interest Forums > Gear & Maintenance
 Not a Member? 
  #1  
Old 06-18-2008
Junior Member
 
Join Date: Sep 2004
Posts: 6
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0
rdunncpa is on a distinguished road
harmonics vs vibration prop issue

Have been going around and around re: replacing my three blade fixed prop with a 2 blade feathering max prop. Boat: Endeavour 32 with a new Volvo 30 (28hp). Yard found and repaired problems re: cutlass bearing, shaft, shaft dripless seal, and engine installation/alignment. Final decree: engine can rev to 3000 (rated 2800 to 3200) and achieve 6 knots in flat water. Vibration I feel is excessive above 2000 rpm is harmonics, not vibration and the engine in not moving on the mounts. Per manufacturer, I'll sea trial with the distributor and he'll show me that the feeling I'm getting may acceptable. I plan to race the boat so they both say stay with 2 blade, but I strongly think I'll ask to return and replace with their 3 blade. They say a 2 blade will always cause more harmonics/vibration and it should be acceptable in exchange for going faster under sail.

Please help!!!
Reply With Quote Share with Facebook
  #2  
Old 06-18-2008
Faster's Avatar
Just another Moderator
 
Join Date: Sep 2005
Location: New Westminster, BC
Posts: 14,390
Thanks: 63
Thanked 160 Times in 157 Posts
Rep Power: 10
Faster has a spectacular aura about Faster has a spectacular aura about Faster has a spectacular aura about
A 3 blade prop is going to run smoother than a two blade.. no question. If you're really going for the Maxprop and want to spend the bucks I don't see a huge downside to going with a 3 blade (other than added cost) in terms of drag under sail.

It's going to be a huge improvement over dragging that 3 blade fixed, and you'll appreciate the reverse capability. The other advantage of the Max is you can, if necessary fine tune the pitch to optimize performance under power.
__________________
Ron

1984 Fast/Nicholson 345 "FastForward"

".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)
Reply With Quote Share with Facebook
  #3  
Old 06-18-2008
Senior Member
 
Join Date: Apr 2008
Posts: 475
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 7
negrini is on a distinguished road
Send a message via AIM to negrini Send a message via Yahoo to negrini Send a message via Skype™ to negrini
I'm colecting impressions of people of this forum asking them "what propeller you have". My previous boat had a folding 3 blade VOLVO and assure you it runs smooth and made a huge difference when sailing. I'm in the market again looking for a propeller for my next boat, and I feel overloaded with possibilities. If for any chance you test your Maxprop, please send me a note about your impressions; I appreciate your time ... Thanks !
__________________
Nave Rara
Beneteau Oceanis 43
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Share with Facebook
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

 
Posting Rules
You may post new threads
You may post replies
You may post attachments
You may edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Folding Propeller Problems slj145c Gear & Maintenance 4 05-21-2008 08:39 AM
Changing prop underwater trantor12020 Gear & Maintenance 16 03-03-2007 12:02 PM
Choosing the Right Propeller Sue & Larry Gear and Maintenance Articles 0 02-04-2003 07:00 PM
Drive Train Vibration Tom Wood Gear and Maintenance Articles 0 10-10-2002 08:00 PM
Choosing a Prop Sue & Larry Gear and Maintenance Articles 0 12-24-2001 07:00 PM


All times are GMT -4. The time now is 08:52 PM.

Add to My Yahoo!         
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
SEO by vBSEO 3.6.1
(c) Marine.com LLC 2000-2012