re: For Our Boat/ Ship Builders

That’s an easy one Jeff. The seams were caulked (pronounced “corked” around here) with cotton and oakum or possible back then on a big ship just oakum. It is tucked into the seams in tight loops with a tucking iron an then driven home with a driving iron. Both are used in conjunction with a caulking mallet. On a large application like this the driving iron would be on a long handle held by one caulker while the “mallet”, would be swung with two hands by another.
Caulking serves not only to seal out the water. It is also an essential aspect of tightening up the whole boat to resist movement.