Reply
 
Thread Tools Search this Thread Display Modes
 
Old 09-08-2018, 06:18 PM   #1
Senior Member
 
City: Lutz
Join Date: Jan 2016
Posts: 473
Fish tail rudder idea!!!

My idea is to make 2 TEAK wedges of 1 X 6 inch size the full height of the aft rudder edge and epoxy glue and bolt it thru ss plate rudder to each side. This goes on my 1982 MT34 . Sand and paint to suit. This will avoid high welding costs and be complete DIY except for wood shop costs.
geoleo is offline   Reply With Quote
Old 09-08-2018, 06:57 PM   #2
Guru
 
Simi 60's Avatar
 
City: Queensland
Vessel Model: Milkraft 60 converted timber prawn trawler
Join Date: Jul 2016
Posts: 5,482
If its a S'S rudder its a 10 minute job to weld angle on trailing edge with 308l rods and $150 arc welder.
Added bonus, you now have an arc welder
Simi 60 is offline   Reply With Quote
Old 09-08-2018, 07:16 PM   #3
Guru
 
Steve91T's Avatar
 
City: Huntersville NC
Vessel Name: Abeona
Vessel Model: Marine Trader 47’ Sundeck
Join Date: Sep 2016
Posts: 898
No way would it be strong enough.
Steve91T is offline   Reply With Quote
Old 09-08-2018, 07:21 PM   #4
Guru
 
psneeld's Avatar
 
City: Ft Pierce
Vessel Name: Sold
Vessel Model: Was an Albin/PSN 40
Join Date: Oct 2011
Posts: 28,148
Quote:
Originally Posted by Steve91T View Post
No way would it be strong enough.
What the teak wedges?

I am guessing done well they would be fine.

My concern would be erosion (unless that is what you meant)....but nothing some epoxy every couple years couldn't handle unless putting a thousand or more hours on it every year.

If something happens to them, no big deal...easy and inexpensive to replace or remove temporarily.
psneeld is online now   Reply With Quote
Old 09-08-2018, 08:02 PM   #5
Guru
 
healhustler's Avatar
 
City: Longboat Key, FL
Vessel Name: Bucky
Vessel Model: Krogen Manatee 36 North Sea
Join Date: Oct 2009
Posts: 5,196
Well, if teak would work, why not starboard?
__________________
Larry

"When life gets hard, eat marshmallows”.
healhustler is offline   Reply With Quote
Old 09-08-2018, 08:02 PM   #6
Guru
 
Steve91T's Avatar
 
City: Huntersville NC
Vessel Name: Abeona
Vessel Model: Marine Trader 47’ Sundeck
Join Date: Sep 2016
Posts: 898
Quote:
Originally Posted by psneeld View Post
What the teak wedges?

I am guessing done well they would be fine.

My concern would be erosion (unless that is what you meant)....but nothing some epoxy every couple years couldn't handle unless putting a thousand or more hours on it every year.

If something happens to them, no big deal...easy and inexpensive to replace or remove temporarily.
Yeah maybe. It’s a lot of force and I can just see them snapping off with one hard turn or two. And by the way, I’m basing my opinion on absolutely no experience what so ever, so there’s that.
Steve91T is offline   Reply With Quote
Old 09-08-2018, 10:23 PM   #7
Guru
 
City: Here
Join Date: Sep 2012
Posts: 2,940
DIRT FREE was extremely difficult to turn at low speed ..... Stainless steel plate bent at 15 degrees and through bolted to the rudder made a huge difference in low speed manouverability. I installed them perpendicular to the thrust.
Attached Thumbnails
new old rudder 1.jpg   new rudder profile 2.JPG   new rudder tail 3.JPG  
boatpoker is offline   Reply With Quote
Old 09-08-2018, 11:01 PM   #8
Senior Member
 
Sabre602's Avatar
 
City: NW Washington State
Vessel Name: Kingfisher
Vessel Model: 37' converted gillnetter/crabber
Join Date: Oct 2017
Posts: 442
Anything could be through-bolted to the trailing edge of a rudder...it doesn't have to be teak. I'm not sure that the epoxy would be necessary and, in that application, that it would contribute much for very long.

If a variety of zincs stick on to a rudder, why not the trailing edge fish tail? The tension force on such bolts would be negligible, the shear forces minimal.

If a solid wedge of teak, why not try it? But honestly, a couple of bent metal plates as shown in boatpoker's picture would cost less to fabricate.
__________________
Anson & Donna

Be kind whenever possible. It is always possible. ~The Dalai Lama
Sabre602 is offline   Reply With Quote
Old 09-09-2018, 06:27 AM   #9
Senior Member
 
City: Lutz
Join Date: Jan 2016
Posts: 473
Quote:
Originally Posted by healhustler View Post
Well, if teak would work, why not starboard?
Good idea except might not hold the anti foul paint!
geoleo is offline   Reply With Quote
Old 09-09-2018, 06:30 AM   #10
Senior Member
 
City: Lutz
Join Date: Jan 2016
Posts: 473
Quote:
Originally Posted by boatpoker View Post
DIRT FREE was extremely difficult to turn at low speed ..... Stainless steel plate bent at 15 degrees and through bolted to the rudder made a huge difference in low speed manouverability. I installed them perpendicular to the thrust.
"NICE!!! Did it improve straight tracking any ???
geoleo is offline   Reply With Quote
Old 09-09-2018, 06:33 AM   #11
Senior Member
 
City: Lutz
Join Date: Jan 2016
Posts: 473
Quote:
Originally Posted by Simi 60 View Post
If its a S'S rudder its a 10 minute job to weld angle on trailing edge with 308l rods and $150 arc welder.
Added bonus, you now have an arc welder
Thanks! Then I would have a welder to move -store and sell----
geoleo is offline   Reply With Quote
Old 09-09-2018, 06:40 AM   #12
Guru
 
twistedtree's Avatar
 
City: Vermont
Join Date: Jan 2013
Posts: 10,092
Wouldn’t the flare created by all these approaches create a bunch of drag under normal operation? I suspect that’s why it’s more common to see articulated rudders?
__________________
MVTanglewood.com
twistedtree is offline   Reply With Quote
Old 09-09-2018, 09:14 AM   #13
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 18,743
Twist,
I agree.
The propwash is way above boat speed. I moved one of my zincs up to the top of the rudder to get them out of the propwash.
As we used to say in aviation the propwash is trying to blow the tail backwards. So it pulls back on the fuselage. Rudders pulling back on boats dosn’t help efficiency.
__________________
Eric

North Western Washington State USA
Nomad Willy is offline   Reply With Quote
Old 09-09-2018, 09:46 AM   #14
Guru
 
Xsbank's Avatar
 
City: Pender Harbour, BC
Vessel Name: Gwaii Haanas
Vessel Model: Custom Aluminum 52
Join Date: Sep 2013
Posts: 3,791
I have a single engine no bow thruster and struggled with controlling the bow in a crosswind. I had a 3 1/2” angle welded to the trailing edge of my rudder and there is no loss of cruise speed, less vibration at cruise and superior low-speed control. I use a welder to attach my anodes so it only cost me another $100 to have this attached and that included the cost of the aluminum. The only part that slowed the process was figuring out how to hold the angle in place symmetrically for the welding. Make it a serious connection or you risk losing the doodad you use. Otherwise think of the consequences if it detaches while backing down. All those other ideas are too flimsy.
__________________
Don't believe everything that you think.
Xsbank is offline   Reply With Quote
Old 09-09-2018, 09:47 AM   #15
Guru
 
psneeld's Avatar
 
City: Ft Pierce
Vessel Name: Sold
Vessel Model: Was an Albin/PSN 40
Join Date: Oct 2011
Posts: 28,148
The million dollar question...

How big of a fishtail to improve turning but small enough to be insignificant drag at cruise?
psneeld is online now   Reply With Quote
Old 09-09-2018, 11:53 AM   #16
Guru
 
MurrayM's Avatar
 
City: Kitimat, North Coast BC
Vessel Name: Badger
Vessel Model: 30' Sundowner Tug
Join Date: Jul 2012
Posts: 5,946
Quote:
Originally Posted by psneeld View Post
The million dollar question...

How big of a fishtail to improve turning but small enough to be insignificant drag at cruise?
Good article below, with enough hints to track down Dave Gerr's article on Thistle, MacLear, Fishtail, and/or Schilling rudders;

https://www.sailangle.com/group-forum/topic/id/1871
__________________
"The most interesting path between two points is not a straight line" MurrayM
MurrayM is offline   Reply With Quote
Old 09-09-2018, 01:31 PM   #17
Guru
 
Seevee's Avatar
 
City: st pete
Vessel Model: 430 Mainship
Join Date: Sep 2016
Posts: 3,499
Quote:
Originally Posted by boatpoker View Post
DIRT FREE was extremely difficult to turn at low speed ..... Stainless steel plate bent at 15 degrees and through bolted to the rudder made a huge difference in low speed manouverability. I installed them perpendicular to the thrust.
Did a rudder mod VERY similar to your, fabricated two pieces of stainless, 6 in wide, bent the aft 3 in at 30d. Bolted it to the rudder tail and did improve steering, however, not quite as much as I wanted. But, when I get aggressive to modify it again, it will be dirt simple and just unbolt the mod, make a new one with the same hole pattern and bolt back on.

Might use aluminum if I try it again... softer, yes, but significantly easier to work with.
__________________
Seevee
Seevee is online now   Reply With Quote
Old 09-09-2018, 02:03 PM   #18
Guru
 
Simi 60's Avatar
 
City: Queensland
Vessel Model: Milkraft 60 converted timber prawn trawler
Join Date: Jul 2016
Posts: 5,482
Quote:
Originally Posted by geoleo View Post
Thanks! Then I would have a welder to move -store and sell----
Mine takes up less space than 1/2 carton of beer.
Stays onboard and is rarely used but invaluable when needed and saves a fortune in paying someone not to mention finding someone to do a relatively simple task.
Simi 60 is offline   Reply With Quote
Old 09-09-2018, 05:32 PM   #19
Guru
 
Xsbank's Avatar
 
City: Pender Harbour, BC
Vessel Name: Gwaii Haanas
Vessel Model: Custom Aluminum 52
Join Date: Sep 2013
Posts: 3,791
I’m not sure where you are getting this high cost for a weldor, they are quite reasonable. However, if you are looking for a fabricator to build something, now it can get spendy.

How much drag do you think is produced by a small piece of aluminum behind a 36” wheel travelling at a max, balls-to-the-wall 10 knots? None of us are driving Americas Cup yachts on here. I’ll bet it’s way less drag than towing your dinghy.
__________________
Don't believe everything that you think.
Xsbank is offline   Reply With Quote
Old 09-09-2018, 05:44 PM   #20
Guru
 
City: Here
Join Date: Sep 2012
Posts: 2,940
Quote:
Originally Posted by geoleo View Post
"NICE!!! Did it improve straight tracking any ???
Zero effect on tracking which was not an issue to begin with. It did help a bit when backing up.

2 pcs stainless bent at 15 degree. 2 ss bolts & nuts, one drill bit. 1hr. installation and about $100 Cndn dollarettes, I believe that's about ten bucks US
boatpoker is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
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


» Trawler Port Captains
Port Captains are TF volunteers who can serve as local guides or assist with local arrangements and information. Search below to locate Port Captains near your destination. To learn more about this program read here: TF Port Captain Program





All times are GMT -5. The time now is 11:11 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012