FAQ: Elliptical Rudder

Catalina has a new elliptical rudder replacement for  both a wing and fin keel C-34. Gerry said the new rudder "feels better"  because it reduces prop wash, is a more efficient foil and requires less  helm pressure. To change it out  you'll have to lift the boat up high enough or dig a deep hole to drop  the old rudder. Cost for pulling the rudder may not be all bad if you also pull the bronze drive shaft and check it for round or replace it with stainless steel, change the cutlass bearing, and do needed machining work on the rudder post for your underdeck autopilot at the same time.   Guess you'll have to bite the bullet as to "is it worth the money" (Ron Hill, Apache #788).

I had an interesting conversation with Catalina today. They tell me that I can put a new style elliptical rudder on my MkI C34. They can send me a new one or I can send them my old one and they will recast a new rudder on the existing stock. It's fairly expensive either way. They tell me that its been done on fin keel versions with pretty spectacular results. The cost is around $1100.00 for the new rudder plus crating and shipping. The new rudder post will need to be drilled for the quadrant. Recasting an old rudder is about $700.00 plus crating and shipping (both ways). Going with the recast approach avoids the need to drill holes for the quadrant but it may mean lifting the boat twice. Once to remove the rudder and again to reinstall. With a new rudder you'd probably only need to lift the boat once (Bob Greenhaus, Summerhaus, #1290). 

The elliptical solution makes technical sense as the very best foils at the hydrodynamic speeds we operate at are elliptical in section. Some of you old propeller aircraft buffs may remember the Spitfire and Mustang wing sections; Almost pure ellipses and very quick in a turn. Also look at the most maneouverable bird wings for a lesson. Elliptical for high turn rate and stall resistance but poor lift to drag ratio i.e. not good gliders. The propeller fighter aircraft boys needed the turn rate more than the speed too. At the other end of the bird, airplane and boat spectrum is high aspect ratio (deep thin foils) for good lift/drag ratio on soaring birds, sail planes, and racing boats (Gary Wiseman; Up Spirits #894).

Apparently hull # 1394, "White Orchid" has the new elliptical rudder - the marina owner thought it was a big deal when Catalina told him that. She has a wing keel and sails great - 28kt winds, full sail (Main & 135%), 4 - 5 foot waves on Lake Champlain! A little wet once and awhile, but otherwise a piece of cake. I was impressed, so was my wife when it wasn't heeling much at all (she really doesn't like that!), but then I don't know what it would have been without the new rudder (Gus Trometer).