I'd stop boiling them at once!
I never boil ribs. You are losing flavor into the water.
From here, put them into a hot oven with a dry rub to flavor them and add some BBQ sauce for the last 15-20 minutes if you like them wet.
They're done when the meat has shrunk back on the bone ends and the bones feel a little loose.
last week my friend made ribs boiling first and then putting it on the bbq.