rudder post cracks?

[B Delli Isabel 98]

I just tightened my rudder post packing be cause I thought I might be getting some water in when motoring. But now I've read that the post itself might leak. How common is this? I'm going down to inspect closer on monday, I'm ready to repair it if needed, But I don't want to have to. It looked awful sturdy, it must take alot  of pounding to develop cracks

[B delli]

actually I meant the glass post thast houses the rudder. I thought I read that the glass can crack.  THanks