Thread Tools Display Modes
Old 04-17-2015, 10:27 AM   #1
City: Whitehall Mi.
Country: USA
Join Date: Jan 2015
Posts: 13
Rudder modification

I recently read an article about a modification for trawler rudders. An academic group reshaped the flat plate rudder of a working trawler with a specific NACA profile. The end result was improved rudder response and increased rudder angle before stalling. Does anybody have any experience with this?

Dan Girvan
Gypsy Spirit
Albin 36

Gypsy Spirit is offline   Reply With Quote
Old 04-17-2015, 10:50 AM   #2
jleonard's Avatar
Join Date: Jun 2008
Posts: 2,407
If you do a search you'll find a thread or two about this.

Jay Leonard
Attitude Adjustment
40 Albin
jleonard is offline   Reply With Quote
Old 04-17-2015, 12:47 PM   #3
Nomad Willy's Avatar
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 11,903
If you have big rudders and go 7 knots you might try rigging your rudder to get more deflection. There were three holes on my rudder horn and I moved the hyd cyl rod attach point to the hole closest to the rudder shaft. Turns real sharp now. Had it that way for many years. You will need to exert more force at the helm to overcome the lesser mechanical advantage. My rudder deflects 45 degrees each way. To take advantage of the increased deflection there's a good chance you'll need to make your rudder bigger. Keep the percentage of rudder area ahead and aft of the rudder shaft the same as the original and if you stray in this regard error in the direction of too much rudder area aft. When you modify things you always take the chance you'll discover things you never thought of .. sometimes in a very painful way. I've had good luck w mods but .......

Definitely do jlenord's suggestion and look in the archives. There have been extensive discussions .. good ones.

North Western Washington State USA
Nomad Willy is offline   Reply With Quote
Old 04-17-2015, 01:00 PM   #4
LarryM's Avatar
City: League City, TX
Country: USA
Vessel Name: Boomarang
Vessel Model: Fales 30
Join Date: Aug 2011
Posts: 646
Do a Google search for:

Schilling Rudder
Fishtail Rudder
MacLear Thistle Rudder

This will get you started in the right direction. There's a lot of available information on these rudders. Be sure to check out YouTube too.
M/V Boomarang
LarryM is online now   Reply With Quote
Old 04-17-2015, 01:27 PM   #5
TF Site Team
Larry M's Avatar
City: Friday Harbor, WA
Country: USA
Vessel Name: Hobo
Vessel Model: Krogen 42-120
Join Date: Nov 2008
Posts: 4,385
Here's a link for a rudder modification that Mike Thompson did on his Defever 40 Passagemaker plus a bunch of other modifications. (His wife, Melissa, has kept his web site up since his passing)

Larry M is offline   Reply With Quote

Thread Tools
Display Modes

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 Off
Refbacks are Off

All times are GMT -5. The time now is 10:40 PM.

Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2016, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012