From the inside

Planks are fixed to the timbers not by screws, but by rivets. A hole is drilled, a square copper nail is pushed through from outside. A round rove is pushed down the nail by a rove iron until it is firmly against the plank. The nail is then clipped off leaving a short stub protruding through the rove. With one person on the outside pushing against the head of the nail with a steel bolster a second person burrs over the stub of the nail with a round head peen hammer until it securely holds the rove in place, as you see in today's Blip. It is explained quite well in this link, particularly the diagram half way down the page. There are one or two Youtube films on the subject - try searching riveting wood boats.