Two Rudders?

Anything goes, as long as it falls under the general forum protocol and rules.
Post Reply
Challenger949L
Almost a Finish Carpenter
Posts: 80
Joined: Sun Aug 21, 2005 10:17 pm
Boat Name: ESPADON Kittiwake
Boat Type: Sabre 28, Alden Challenger
Location: Central Virginia

Two Rudders?

Post by Challenger949L »

Check out this Cal 36 on ebay, it appears to have two rudders....very odd.
Jimmy Small
http://cgi.ebay.com/ebaymotors/1968-Cal ... dZViewItem
User avatar
Tim
Shipwright Extraordinaire
Posts: 5708
Joined: Tue Apr 01, 2003 6:39 pm
Boat Name: Glissando
Boat Type: Pearson Triton
Location: Whitefield, ME
Contact:

Post by Tim »

The one on the trailing edge of the keel is probably a trim tab, like the 12 meters used for years. I guess the theory is that by adjusting the trailing edge of the keel with that movable appendage, lift can be increased for higher pointing ability. Or something like that. These things never became commonly used. Is if because they only really work in specific designs or situations, or because of the additional complexity, I wonder.

Image

Imagine sailing with these two tillers in your cockpit, though. That must be a bit awkward. Good for starting conversations with strangers, though.

Image
---------------------------------------------------
Forum Founder--No Longer Participating
Robert The Gray
Candidate for Boat-Obsession Medal
Posts: 351
Joined: Thu Feb 19, 2004 1:54 pm
Location: Oakland California
Contact:

Post by Robert The Gray »

I can imagine those tillers in a rolling anchorage with a running tide breaking the legs of yur guests as yur havin a bit of a nosh. not to mention a lovely way to really foul the mainsheet.

r
Former Owner: Whisper, now Alma 1960 WC Triton
Whisper Projects
Daysailfilms
Figment
Damned Because It's All Connected
Posts: 2847
Joined: Tue Apr 08, 2003 9:32 am
Boat Name: Triton
Boat Type: Grand Banks 42
Location: L.I. Sound

Post by Figment »

It's a learn-to-sail vessel. The student takes the helm of the keel-mounted rudder, but the instructor controls the spade in case the student tacks the boat across the path of an oil tanker.
Brilliant!
Figment
Damned Because It's All Connected
Posts: 2847
Joined: Tue Apr 08, 2003 9:32 am
Boat Name: Triton
Boat Type: Grand Banks 42
Location: L.I. Sound

Post by Figment »

(oooooo! Mr. Cotter! I have another answer!)

Self-propulsion. Simultaneously scull the two tillers out of phase.

Anyone remember that pedal-powered Hobie kayak thing with the swishing underwater blades?
User avatar
Rachel
Master of the Arcane
Posts: 3044
Joined: Tue Dec 07, 2004 7:59 pm

Post by Rachel »

I had a dock-neighbor once who planned to mount swim-fin-like appendages to the after end of his hull (one on each side). The plan was that as the boat pitched in an ocean swell, they would propel the boat like fins on a swimmer do. I'm not sure if he ever implemented the plan (I bet I could find out though).
Hirilondë
Master of the Arcane
Posts: 1317
Joined: Thu Dec 28, 2006 8:50 am
Boat Name: Hirilondë
Boat Type: 1967 Pearson Renegade
Location: Charlestown, RI

Post by Hirilondë »

The designer couldn't decide between a full keel/keel mounted rudder and a fin keel/spade rudder, so he did both.
Dave Finnegan
builder of Spindrift 9N #521 'Wingë'
--------------------------------------------------------------------------------------------------------------------------------------------------------------------
Gresham’s Law of information: Bad information drives out good. No matter how long ago a correction for a particular error may have appeared in print or online, it never seems to catch up with the ever-widening distribution of the error.
User avatar
Tim
Shipwright Extraordinaire
Posts: 5708
Joined: Tue Apr 01, 2003 6:39 pm
Boat Name: Glissando
Boat Type: Pearson Triton
Location: Whitefield, ME
Contact:

Post by Tim »

Rachel wrote:I had a dock-neighbor once who planned to mount swim-fin-like appendages to the after end of his hull (one on each side).
Did he by chance look like this?

Image
Image
---------------------------------------------------
Forum Founder--No Longer Participating
George ( C&C 40 )
Skilled Systems Installer
Posts: 254
Joined: Thu Jan 06, 2005 12:39 pm
Location: Williamsburg, VA

Post by George ( C&C 40 ) »

That is possibly the best post I have ever seen.

George
Figment
Damned Because It's All Connected
Posts: 2847
Joined: Tue Apr 08, 2003 9:32 am
Boat Name: Triton
Boat Type: Grand Banks 42
Location: L.I. Sound

Post by Figment »

...and you just know that it requried ZERO search-time because those pics are in Tim's screensaver rotation.
jpmathieu
Almost a Finish Carpenter
Posts: 89
Joined: Thu Jan 04, 2007 5:05 pm
Boat Name: Twize
Boat Type: Pearson Renegade
Location: Mattapoisett Mass
Contact:

Post by jpmathieu »

or is that a secret project Tim is working on?
JP
Renegade #153 TWIZE

It never ends!
JSmith
Almost a Finish Carpenter
Posts: 78
Joined: Sun Sep 03, 2006 9:38 am
Location: Southport, ME

Post by JSmith »

Believe it or not my Dad designed the first trim tab- that's on the rudder for Sparkman & Stevens on Intrepid. It was controlled w/ a small wheel inside the larger wheel. The idea was to gain lift to windward by creating I guess a foil on the trailing edge of the keel- The wheel allowed you to change it port or starboard as you tacked. I also think it could be locked in with the main rudder to give you more rudder power. My older brother still has the working model of the whole gizmo Dad made to show Olin & Rod Stevens (sp?).

He also came up w/ the coffee grinders hanging under the deck rather than topside to get weight & windage below decks. I remember sitting in a chair in our cellar pumping handles with my arms and then feet so he could determine the best way to grind. Bottom line was hands were much faster but not as strong. That was fixed by shifting gears- which he changed from the old style of buttons you hit w/ a fist to a foot pedal that allowed continuous grindng. I don't think he was too popular w/ the grinders who spent the race below decks rather than up in the breeze!
feetup
Almost a Finish Carpenter
Posts: 99
Joined: Tue Jan 16, 2007 11:35 am
Location: Ladysmith, Vancouver Island

Post by feetup »

There is no question about it, what you see is actually a FLAP. As the keel approaches stall speed the FLAP is lowered enableing the craft to land and take off with more lift at slower air speeds. Every pilot knows THAT! Heck, I know that and I'm not even a pilot!

Feetup, "Pilot to co-pilot..."
Post Reply