Oakum and Traditional Caulking Techniques

Caulking is the centuries-old craft that keeps a wooden boat afloat. At the heart of the traditional method is "oakum".

What is oakum?

Oakum is a filling material of cotton or flax fibres driven into the seams. It's set into the seam between planks with special irons, compressed to form a watertight plug.

Traditional steps

• Seam preparation: old filling is cleaned out and the seam opened.
• Driving the oakum: the fibre is set into the seam at the right tightness and in the right layers — too little leaks, too much strains the wood.
• Paying: the top is sealed with traditional stopping or a modern flexible compound.

Working with the wood's movement

The secret to good caulking is accommodating the movement the wood makes as it swells and dries with moisture. Oakum that is too hard or wrongly set causes the seam to open or strains the plank. So caulking is work that takes experience and a delicate hand.

Tradition + modern

Today we combine traditional oakum with modern flexible sealants according to the boat's construction. We do caulking and woodwork under our wooden boat refit service.