I'd beg to differ with you on this.

I realize that my H17 rudder castings aren't made out of solid steel, but I've had to sail a good 5 miles in a stiff 15 knot breeze with my rudders up because my traveller broke and I wanted to stay within 10' of the beach.

While I wasn't all that sure that my tillers could take the force, the castings, which are 12 years old, did fine.

In fact, I'd wager to say that the boards would break before the castings. I'm not going to offer mine for testing though.