Three days into Leg 5 and for Volvo Ocean Race rookie Ian Walker, the learning curve continues upwards in the Pacific Ocean.

Luckily for us, the Green Dragon skipper has invited us into his blackboard jungle. Pay attention at the back.

On today’s curriculum was geography, biology and home economics. His latest essay read … "my geography lesson is continuing as we have now swept past Korea and Japan out of the Yellow and China Seas into the Pacific. At daybreak today we had some stunning scenery as we threaded our way through two Japanese islands (well volcanoes actually) called Kuchino Shima and Nakano Shima. That’s the closest I have ever been to Japan – these islands look a great place to explore.

"It has been a tough 36 hours with winds in the 20's and 30's and lots of pressed up reaching. The decks have been awash and it has been survival suits, lifejackets and harnesses all round day and night.

"We are catching up on chores like tidying the boat, checking for damage, eating and bailing out the water that finds its way into every compartment of the boat. The water temperature has risen from five degrees at the start, to 21 degrees now, so the thermals, hats and gloves are coming off. I'm sure it won't be long before we are moaning about it being too hot.”

From PUMA’s Media Crew Member Rick Deppe, there was some arithmetic to ponder. We have Mrs Deppe to thank for this ...

"I sent my wife a note that she told me really helped her to get her head around the leg we have ahead of us,” he wrote. “It went something like this: 48 to 72 hours to get away from the Quingdao/China coastal region, two weeks give or take to New Zealand, 10 days in the Southern Ocean to Cape Horn where we turn left and then 8 days up the South American coast to Rio.

'We have 20 food bags for a 40-day leg’

"There are any number of ways to break down a trip like this. A simple one would be to count down the food bags. We put two days’ worth of food into one bag and we have 20 food bags onboard, anticipating a possible 40-day leg.

"Bag One came out two nights ago around midnight, we had porridge for breakfast and followed by pasta primavera and Spag Bol. It will be nice to empty the first bag and start the next one knowing that it's one less bag cluttering the boat up and six meals nearer to some nice Brazilian steak. Does a two-day food bag put us a tenth of the way there in distance maybe? Probably not.”

The alternative maths equation, suggests Deppe, is to use the “sched-to-sched” method. This involves utilising the three-hourly position report (sched) issued by race HQ. The scheds tells each boat how it has performed relative to their rivals over that three-hour period.

This is the method favoured by PUMA’s navigator Andrew Cape but with a novel calculus factored in. True to his Australian roots, “Capey” has an Excel spreadsheet which breaks the Distance To Finish (DTF) into the number of “Hobarts” (the 620-mile Sydney to Hobart Race) to go.

Using Capey’s Sydney to Hobart system, Deppe has worked out that PUMA has “about 19.2 Hobarts to go”.

Then there is the “prison countdown” system. Deppe explains: “On the wall in the media station I have the days and weeks marked off with marker pen, every sixth day I put a line thru and start the next row, I can tell you that since we left Newport Rhode Island on what we called Leg 0 we have spent 70 full days on this boat and since Alicante its been 61 days. This leg to Rio will reduce my 140-day sentence significantly.”

By the 16:00 GMT Position Report, our Race Viewer showed leader Ericsson 4 making good its great escape from the pack with 897 miles – nearly one and a half “Hobarts” – ticked off on this leg.

E4 held a 15-mile lead over second-placed PUMA while Ericsson 3 (+66 Distance To Leader) had stretched her advantage over Green Dragon to 18 miles. E3’s fellow late beginner, Telefonica Blue was a further 119 miles adrift.