How was ahab observed readying the spare boat?

Here is the quote where this happens,

"Ahab was now and then found bestirring himself in the matter of making thole-pins with his own hands for what was thought to be one of the spare boats, and even solicitously cutting the small wooden skewers, which when the line is running out are pinned over the groove in the bow: when all this was observed in him, and particularly his solicitude in having an extra coat of sheathing in the bottom of the boat, as if to make it better withstand the pointed pressure of his ivory limb; and also the anxiety he evinced in exactly shaping the thigh board, or clumsy cleat, as it is sometimes called, the horizontal piece in the boat's bow for bracing the knee against in darting or stabbing at the whale; when it was observed how often he stood up in that boat with his solitary knee fixed in the semi-circular depression in the cleat, and with the carpenter's chisel gouged out a little here and straightened it a little there; all these things, I say, had awakened much interest and curiosity at the time."