The skeg is usually what shears off along with the prop blades. A new prop will resolve that. You have two options for the sheared skeg:
1) Find someone who can weld aluminum
2) Get a bolt on skeg gaurd to essentially replace the missing skeg. Such as: http://skeggard.com/
Originally Posted by Fippe
....the rest off the lowest part of the out drive is a bit crocked.
This part I'm not completely clear on what you mean. As for the bolt....here is a good rule of thumb. If it previously took a BOLT, then glue will probably not be sufficient.
Whatever it is, drill it and reverse it out and replace it.