176 Rudder Story - again

Cyclone wrote: KENO wrote: Here's a whole different viewpoint to consider on the 11A vs SS rudder An 11A rudder is a manganese bronze casting around a shaft of weaker material like brass If you hit something hard enough with your 11A rudder they mostly all tend to break in the same spot........right flush with the bottom of the boat like the picture below.. No hull damage for the most part. Looks like there's a built in weak point Just unhook the tiller arm and let the broken shaft fall out the bottom, slap a new one in along with whatever else you destroyed Now take that welded SS rudder and hit the same thing, is it gonna break in the same fashion or is it gonna tear apart a bunch of fiberglass instead as it's taking the hit. Is there a built in weak point? Or is the hull the weak point in this case? Beats me    I've never heard of this built in weak spot. What about the bronze dudders with a ss shaftwill they break at the hull or do hull damage

I'm not sure what a dudder is but if you see a bronze rudder with a Stainless Steel shaft, the shaft is probably engineered to break in the same spot instead of wiping out the bottom of the boat.

Down below is a link to the Marine Hardware catalog, if you go to the rudder section you'll see numerous references to the rudders having an "integral breakaway post design" on their bronze rudders with a Stainless Steel shaft

Inboard rudders start on page 34, but the whole catalog is a good read   

Now whether every rudder built by other outfits is built the same way........who knows

Maybe the 11A CC rudder was accidental or maybe it was designed that way but I'd rather break the rudder like that than damage the rudder and rip out the rudder port

And as far as that Stainless Steel CC rudder I'd say that fits in the "who knows" category too as to how it was designed/built.

link

One time I launched my boat at the lake and while I was parking the truck I asked my Dad to hold onto it. It was nosed into the beach at the time and clear of any sand. By the time I got back wakes had pushed the stern of the boat towards the shore so now the boat was sitting at a 45* angle to the shore line. I could see the boat rocking back and forth with the waves, and the boat high sided on the fins (I assume).

My long winded story is wondering if the donor boat of your rudder had washed up stern into the beach and bounced against the sand long enough to bend the shaft. I don't think you'd be able to see any marks in the rudder from the sand.

davidg wrote: Pete....No damage at all. Looks like the day it left the foundry. I just can't figure how it got bent back like that. I wouldn't think water pressure would do that, even over a long time. So, do you think it would be okay to use on a big old lumbering Martinique crusing at 20 mph most of the time?

In the words of Yogi Berra, it's like deja vu all over again.

It's still bent   

Click on the link below

link

davidg wrote: Is the 11A rudder shaft meant to be straight, or does it have a slight bend to it? I picked one up a few years ago as a spare should it ever be needed that had a slight bend to it. No damage to rudder whatseover though. Would the water pressure cause it to bend back like that, or was that factory? I figure it should work on the old Martinique regardless.

Hi Larry,
I measured the O.D. of the rudder port from the Stainless steel rudder, and it's 1.975"
Now we need to get somebody to measure the O.D of the port for the 11a.

Don