1066: William sinks in the Channel

Storms are not exactly a rare thing in the English Channel. Let us say that in September, 1066, a sudden, rather nasty storm pick up in the Channel, during the crossing, and William is swept overboard and drowns, along with a number of other people in his fleet. In the confusion, some ships head for the British coast, others return to Normandy, and a few sink. This has no effect on the Battle of Stamford Bridge (which, IIRC, took place a few days earlier), of course - Harald Hardrada still dies on schedule.

So, what other challengers, if any, are there for King Harold Godwinson? What sort of king will he be, with this apparent miracle saving him from the Norman invaders?
 
A question based on ignorance- were William's sons sailing with him in the fleet that landed in England? I'm thinking of Robert Courteheuse, Richard of Bernay, and William Rufus in this case. If they drowned too, who would inherit the Norman claim on England? Seeing as William Rufus was only around ten years old at the time, I am inclined to think that he remained in Normandy during the invasion. So if Robert and Richard both die with their father, the youngest son inherits Normandy and his father's claim on England. Might he, upon reaching adulthood, choose to fulfill William I's mission and invade ~1090?
 
The heir of William could try another invasion at a later date, but 1066 had favourable circumstances; and was one of the sons of William as capable as William was? In 1066 there were multiple invasions and a disputed succession... For instance a POD might be Edgar the Aetheling, who had a legitimate claim on the throne, so he might start a civil war to claim his birthright and this could result in a new window of opportunity for the Norman dukes.
 
Top