By the numbers – Ocean Valour

In the last 42 days Tom and Lawrence have covered an incredible 1823 nautical miles (nm).

When they started they had 2900nm in total to travel however, unless the were going to row over land they would need to go a little further to keep Yves in the ocean (about 3150nm if they were to follow the shortest route between all their waypoints.)  This is part of the reason by one nautical mile rowed does not result in being one nautical mile closer to Salcombe.  On average so far Tom and Lawrence have rowed 43nm per day and made 26nm towards Salcombe.  This is significant difference of 17nm between distance rowed and distance towards Salcombe each day.

Part of this can be explained by the route and the need to row around particular features such as the Grand Banks and the mainland of the USA when they departed from New York.  The remaining difference can then be explained by the boat not necessarily in a straight line as waves, wind and current constantly work to knock the guys away from the shortest possible route.  This was witnessed by all of us just a few weeks ago when Yves was stuck in the circle of current that took Tom and Lawrence 10 days to break out of.  The Big Vortex of Doom (BVOD) lost the lads 10 days of progress so we can also look at some of these calculations with the somewhat rose-tinted expectation that this won’t happen again.

When we ignore the effects of the BVOD the averages creep up a little higher.  Now the guys are rowing 44nm per day and making 35nm towards Salcombe despite the dog leg in the route.  This is a much smaller difference of just 9nm per day.

There is even more good news for the future when we consider that now the team have passed the last of their main geographical obstacles they can point directly towards Salcombe and we can expect to see the difference between the miles rowed and the miles made towards target, decrease dramatically.  So let’s guess that Tom and Lawrence will start to be more accurate with their steering and loose only 4.5nm per day.  Giving us an expected average mileage towards Salcombe each day of around 40nm.

So with 1785nm left to row we can expect the crew to maybe take another 44 days before they finish, which would give them a crossing time of 86 days – July 27th.

However, there is an awful long way yet to go and many other aspects to the calculations that we have not considered here.  As they eat their food rations the boat will become lighter and thus faster but they will be more tired having spent months at sea and so their speed may drop.  The Gulf Stream which has helped and hindered their progress to date should become less influential in their future progress will that reduce their pace or will the benefit of not getting stuck in a westerly current increase their average speeds?  Or will they get stuck in another swirl of current halting progress for a few days?  Maybe they will find an extra burst of speed as they get closer to Britain but will their need to be more precise with their course force them to slow down?  Only time will tell but it is clear to see why working out when they will arrive is no exact science.

The team started out with 90 days of food rations so at the moment it looks like it is almost the perfect amount.  We also know that there have been a few days (especially near the start when they weren’t eating all of their rations and so have a little more in reserve). The support team continue to monitor the amount of food on Yves and the teams progress and stand ready to advise Tom and Lawrence accordingly.

NB:// All figures and distances listed above are rounded up and based upon the Earth being a perfect sphere. This is not 100% accurate but provides us with enough information to analyse and assess the state of play.  Timings and arrival dates are based on the latest daily position gained on 14th June at 15:00.

The battle wears on but champions remain unbowed

via By the numbers – Ocean Valour.

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