At this point, the hatch is a full week overdue. The loons are beginning to lose interest in incubating the eggs and the nest is occasionally being left unattended for an hour or so, as shown in this video. For all practical purposes, the chances of a hatch are nil.
This pair overincubated last year and abandoned the nest at 36 days. It remains to be seen how long they will continue to occupy the nest this year.