"Malta is now as of a few hours ago saying that they could be back in the game so we're hopeful that's the case.
"Stars and Stripes is going through another management restructure and a restructure of the team at the moment over at Long Beach but Long Beach Yacht Club is still fully behind the Stars and Stripes challenge.
"And then you've got the Dutch team with Simeon [Tienpont] up in Holland there who is still working full speed ahead trying to make the deadline.
"So there's other things at play that will come into this soon, which is at some point you've actually got to start building a boat to be able to sail in Cagliari in April next year."
Despite some worries about the three new challengers, Shoebridge said the three teams that have entered early are one of the strongest in recent years, also adding that Team NZ are in good shape.
"It's early days but we're looking good and we're full speed ahead down here at the moment. We're about a 110 people now with the team and we're busy building a boat.
"It's been a pretty frantic year and a half or nearly two years since the Cup but we haven't really stopped and it's going well.
"The three teams that have entered early into this event are very strong. They're probably the strongest group of challengers we've had for years I would say."