It took exactly 90 minutes to bend the bottom, which is almost two inches thick. Once finished we left it there for about three hours, turning to the layout of our side planks while we waited. Then we rushed the bottom into the shop - it was straightening as we did so - and propped it into place using stout poles against the shop’s framing, and bending the timber with a car jack.
Murakami san moved very quickly to prop the plank, so I guess the benefits of fire bending wear off quickly. I simply don’t understand the physics of it well enough.
Over an extended lunch break (we were giving the bent bottom time to take its shape) we watched two TV programs about Murakami san. We also talked a bit about his past and he said his father was a boatbuilder and he had studied with him. They didn't get power tools until about 1965 but even using only hand tools they could build an isobune like ours in about ten days. He recalls building about twenty boats a year. He told me prior to this project this would be his final boat, one that he plans to keep and use for fishing, but then his wife interjected and basically said that the idea of retirement has been revisited several times, so one never knows.