With neither of the Ericsson boats emerging from StealthPlay yet, all we can tell you with any certainty is that both are still over 50 miles from the finishing line. Within 50 miles, their positions become visible - StealthPlay or not.

So we head into what will be a final night - or partial night - at sea for the leading boats, not knowing exactly how far off they are.

Aksel Magdahl, navigator on the presumed leader, Ericsson 3, spoke to Amanda Blackley earlier today and said he anticipates a finish as the sun comes up in the morning, which would translate into a finish near 0830 GMT.

"It's looking alright. (When) we get within 50 miles I think it will be quite light. We might get stopped there for a few hours but then the land breeze in the morning should take us in. I hope so. I think it will be sometime around sunrise probably."

But if the wind holds through the night, the finish could be several hours earlier than that. The team's shoreside meteorologist, Chris Bedford, certainly thought that was a possibility earlier in the day.

"The most significant area of uncertainty and potential for slowdown is very close to the finish. During the day, there is normally a sea breeze which blows from the south and southeast along the coast. It would be best if the boats could arrive with this breeze. However at night, the sea breeze shuts down and a very light northeast to north land breeze develops. Between the SE gradient and the land breeze there is often a nearly calm convergence zone, sometimes filled with thundersqualls. At the moment, I think Ericsson 3 has a reasonable chance of getting in before the breeze shuts down...but it may be very close."

For race fans, the StealthPlay before the finish can be agonising. But the teams have a good reason to make the play. In addition to the possibility of being able to make an unexpected move whilst in hiding, being in Stealth denies the opposition the wind readings coming off your boat with each position report:

"We're hiding so we're not a weather buoy for all the rest to see what's waiting for them ahead," was the way Aksel put it to us this morning.

To this point, PUMA has remained in plain sight, and have been making good speed towards the finish line (over 17 knots at 2200 GMT) for most of the day.

Green Dragon too are in a stronger position, having seen off, for now at least, the challenge from Telefonica Blue. After watching their advantage nearly disappear, the Dragons have found the breeze, and built up a comfortable margin (197 nautical miles) again. For Telefonica Blue, it's been a slow day.

"We continue to sail upwind in light shifty breeze with our big Code 0, our priority for now to get north in the hope of finally picking up the wind that will take us into to Rio," wrote Blue helmsman Simon Fisher. "The breeze has been teasing us all morning, tempting us with the wind shift we are waiting for and then before you know it it shifts back and drops again. This is proving frustrating for some and others now are more philosophical as they resign themselves to a slow ride up to Rio."

And so, we wait. Updates will be provided as we have more information on the progress of the leaders. When they come out of hiding, you'll be the first to know!