Grand-Am, Rolex 24 at Daytona - Hours 13 to 15

As the race enters its second half under caution, Rob Bell hands over the #48 Paul Miller Racing to Tim Sugden with the car still very much in contention; "It's going well," said the two-time GT2 LMS champion. "We'd worn the brakes down to the metal after about seven hours and the gearbox is a bit clunky, but its holding together well."

Why are there so many yellows? "There's a lot of debris out there. I wouldn't say it's bad driving necessarily, but there are definitely some cars circulating that shouldn't be."

Mark Blundell's stint in the #23 Riley included comings-together with a DP and a GT and a second new nose. Despite this, he managed to pull back a lap before handing over to Zak Brown. 

The race goes green again after 15 minutes of the 13th hour.

03:56 380 laps completed. Memo Rojas leads from Fittipaldi and Donohue.  In GT, Sugden is seven seconds behind Tom Long in the leading #40 Mazda.

OK - the dsc deputy ed is going to go and collapse under a desk somewhere so bear with us as we try to kep up with proceedings for a little while from this side of the Atlantic!

We'll be catching up with the Hourly times in the next hour or so too so do keep checking that out.

For now though Memo Rojas leads the Rolex 24 Hours in the #01 CGR Riley from Christian Fittipaldi in the #9 Action Express car, the gap just 1.6 seconds between this pair.

Running third is the #5 Action Express car - David Donohue pulling away from Tracy Krohn's now 4th placed Lola who will soon be inder pressure from the last car currently on the lead lap, Scott Dixon in the #02 CGR Riley 

Dixon breezes by the Lola and is making up ground on the leading trio

Henzler pits in the leading GT class TRG Porsche just before the half hour, it's relatively short but it wasn't altogether routine. and the class lead baton goes to Tom Long's #40 Dempsey Racing Mazda

Fittipaldi's latest pitstop meanwhile puts Dixon up into third overall and closing by around a second a lap on the second placed car.

The leader completes 400 laps after 13 hours

The leading pair pit soon afterwards - Dixon leads the Rolex 24 for a single lap before he himself heads to the pits - Joey Hand takes over the #01 Riley and he leads the race after 403 laps, Jamie McMurray climbs aboard #02.

In GT Tim Sugden is reeling in Tom Long for the lead and Wolf Henzler, having lost two laps with the earlier stop is looking now to climb back up to third

McMurray is having a fine old dice for third with Christian Fittipaldi.

05:04 As DSC Florida once more takes the reins, your scribe can confirm that it is very cold outside and that it is beginning to get misty as dawn approaches. We've still a couple of hours of darkness to go before the sun can burn any mist off, so we'll see if it becomes an issue in the interim. 

With 421 laps gone, we're down to four cars on the lead lap, and fascinatingly they comprise two Porsche-powered Rileys (Action Express) and two BMW-powered ones (Chip Ganassi). Hand leads Donohue by ten seconds, but 50 seconds further back Fittipaldi is right on McMurray's tail.

In GT Long is off the hook for the time-being as Sugden pits to hand over to Bryce Miller, while James Sofronas is now third in the #54 Black Swan Porsche.

05:16 FCY #16. Reason unknown.

The Muehlner Porsche has dropped to 14th in GT after an encounter with the wall for Mark Thomas led to the water pump having to be replaced.

All four leading DPs pit together - #01 and #02 get back out ahead of the two Action Express cars; the team taking advantage of the caution period to attend to the brakes on both Rileys. The #5 leaves a minute or so later, followed by the #9 and they stay on the lead-lap. The Ganassi drivers are unchanged, but Buddy Rice and Max Papis are now in the AE cars.

No indication yet as to the cause of the caution, as the fog thickens.

05:30 Papis brings the #9 back in and drops off the lead lap.

05:36 A quick trip to the platform above the garages confirms that the fog is drifting across the speedway. SPEED.com's Marshall Pruett has just tweeted that visibility is very poor in the infield. It could well become a significant factor in the race.

Ollie Gavin has just climbed out of the #07 Banner Racing Camaro. All three of the GT.Rs have had a horrendous time, but none have given up despite being 51 laps (Stevenson), 64 laps (Banner) and 80 laps (Autohaus) off the class lead. 

05:39 The #23 United Riley is undergoing a rear-pad change in the pitlane. 

The fog is now the reason for the continuation of the caution period, with Mark Raffauf admitting that he has no clue as to how long it is likely to remain.

The #17 Burtin Racing Porsche is a confirmed retirement with a snapped right-front ball joint, while the current caution began when the #81 Ferrari found the T1 tyre wall while under the care of Doug Baron. 

06:00 No sign of an end to the current FCY. The caution period has, however, conspired to allow Nic Minassian and Justin Wilson to get back onto the lead lap; and despite all its recent problems the #23 Riley is now only two laps down.

As the caution period reaches 50 minutes, the top ten positions in each class are as follows:

DP - 01, 02, 5, 6, 76, 9, 23, 60, 55 and 10

GT - 40, 48, 67, 54, 66, 41, 44, 59, 70 and 4

38 of the 48 starters are still running; some more effectively than others.

06:22 At least another 20-30 minutes under yellow before the sun can start to burn the fog off.