Cracked Kick-Up Rudder Side Plates

[Aldo]

Please take a look at the attached photos. They show that the side plates on two of our Catalina 22s rudders have cracked. The side plates on my rudder are not cracked, but I have shear pinned my rudder down for a long time, which greatly reduces the side stress on the rudder. The two rudders that we have that are cracked, (one is a spare rudder), were owned by sailors who did have problems with the rudders kicking up, when they didn't want them to.

My question is have any of you found a source for replacement side plates? My son asked Catalina Direct, and they don't sell just the side plates. They want to sell the top assembly without the blade, which costs many hundreds of dollars. He said that he may end-up drawing the side plates up and having some machined at a shop, and then getting them anodized.

Thanks, Aldo

 

[jfrench]

Some aluminum alloys can be TIG-welded. Check with a high-end welder in your area.

 

[Bilbo]

Interesting issue. Do we think that a main contributing factor is that the rudder may have been pressured in use when it was in the up position?

 

[jfrench]

I think it's just a design weakness. I have the same cracks on my '86 rudder. I've ignored them to date, but will look at welding/ replacing at some point.

 

[Bilbo]

Hi jfrench,
I don't have this problem "yet" on my 1987 rudder. I would say that it may be a design issue because of the closeness of these two screws but design may be a contributing factor in a situation that caused the cracks. For example, trying to steer the boat becomes much more stressful on this rudder area when the rudder is raised or that the boat may have grounded on the rudder and then some amount of side pressure caused the problem. It would seem that any further cracking beyond the immediate area may be less likely but I can't say. It also may be that with some longer screws and an additional plate of similar material over this area on both sides, the strength would be restored.

 

[txtowman]

Hi jfrench,
I don't have this problem "yet" on my 1987 rudder. I would say that it may be a design issue because of the closeness of these two screws but design may be a contributing factor in a situation that caused the cracks. For example, trying to steer the boat becomes much more stressful on this rudder area when the rudder is raised or that the boat may have grounded on the rudder and then some amount of side pressure caused the problem. It would seem that any further cracking beyond the immediate area may be less likely but I can't say. It also may be that with some longer screws and an additional plate of similar material over this area on both sides, the strength would be restored.

I think if you put double washers and longer bolts in them they would last a long time,

or make a plate a little bigger than the spot, like bilbo says,

At the catalina experiment site the guy has new plates made of bright tred alum plate.

 

[Ray Bowles]

That should be an easy fix for most welding shops. I would have a larger plate welded over those corners and drilled to mount the same bolt pattern.
Ray

 

[Chris Patterson]

Just my one and a half cents worth, but with access to a plazma cutter, a man could whiz out those plates w/ aluminun in short order. And, use thicker plate, (would have to widen the tiller brackets). OR, my favorite, stainless steel if weight is not an issue. Bearing in mind, when you beef up a component, the weak link generally ends up elsewhere..

 

[Diamondjet]

Just a note. Last winter I filled in the groove formed in the sideplate from wear by the locating pin with JB Weld. This quick fix has worked for a full season. No unintended kick-ups.