I found this while doing some reading...
From Wikipedia...
At around 05:30 on 6 May 1682, Gloucester struck a sandbank off Yarmouth, Isle of Wight. In a strong Easterly gale the ship was pounded against the sand until the rudder broke off and the ship was holed. The Duke of York and John Churchill (the future Duke of Marlborough) were rescued in the ship's boat.
So what if James wasn't rescued?
How does this change the development of England. There's not going to be a Glorious Revolution, at any rate.
There's a clear succession of his niece, Mary, but Would she be a queen regnant or would she insist on William being make King? Mary is still young enough but there has to be some suspicion that there are no children and that there might not be any children.
Anne's not Married yet, though. Would Charles still go for the Danish match with George? Is there any chance the would set their sights higher with George's nephew, the future Frederick IV? I don't think so, given that he's only 11 or so but....
Even if we leave things as OTL Anne's two eldest daughters died of smallpox. What if one or both of them survived?
Thanks in advance for your thoughts,
David