There are plenty of examples of boat loosing the rudder.
Some probably due to poor maintenance or bad construction.
But there are also boats that report hitting something submerged damaging the ruder (or loosing it completely).
Don't think a skeg hung rudder rudder make your boat immune.
There was a well maintained Norwegian boat that lost it's rudder during the last ARC (2012).
They report that the rudder must have caught something, probably some kind of fishing gear.
Wind 20-35 knots ++ astern
Waves 4-5 meters up to 6-8 metes with some larger ones in between
Boat speed around 8-9 knots
Position is 331 nm North of Cape Verde
Boat equipped with wind wane steering, proved to be to small when the rudder disappeared.
They managed to set course towards Cape Verde, but the could not go to harbor with out assistance.
They passed Mindelo with a CPA of 35 nm, when they got the tow they where 65 nm off Mindelo and heading directly for the cliffs of "Sao Nicolaou" without being able to steer the boat clear of "Sao Nicolaou".
Plugged ruder tube on the same boat
So depending on how far offshore you are planning to go I think a complete backup solution will be in place.
Remember that the balance of the boat will change when the rudder is lost.
The tow cost 6500€ for only 65nm