To repay a seam is to melt and pour a new layer of marine pitch or tar over the oakum driven between hull planks. This seals the gap against water ingress and protects the caulking material from rotting. Shipwrights must periodically scrape out the old, brittle compound and repay the seams during drydock maintenance to keep a wooden vessel watertight.
Heard on the job
Once the oakum is driven hard into the deck seams, we'll melt the pitch and repay the whole section before it rains.