The joy of having time over Christmas. I should probably have gone out for a run this morning and taken advantage of the frozen ground, but I had a slight niggle at the top of the quad on my last run, which didn't seem to be impacted by the Concept 2. So I set off at what I thought was a sustainable pace and decided to see if I could keep going all the way to 25,000m. There was a moment of stress at about 6000m when the jambox ran out of power and the music died, but CET Junior was summoned to provide a cable and get the bluetooth going again. Then it was plain sailing (as far as you can sail on steel contraption sitting on a concrete floor) up until the half-marathon point (my previous distance best) when it started to feel like hard work. But by then it was almost over and the magic of almost there took over (after a bit of a wobble when I realised that 10% to go was still 2500m).
Contact points were OK, just a couple of warm points on callouses, which suggests that a marathon would be possible, although I would have to think about hydration and energy drinks. If anyone has rowed a marathon on a Concept 2 would be interested in what they did with feeding/drinking strategies.