calker

But in the afternoon one man, a great burly calker, threw up his hands and then fell down dead.

This Finn, Olgaref by name, was a notable calker and with some others was slung over the bow to calk the gaping seams.

He was afraid to seek employment as a calker, lest spies from his master should be on the watch for him.

This process is called calking, and the furnace is called a calker furnace.

I myself gave some thought to the advisability of a "professional calker."