Wooden Boat Building Methods

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Methods of Wooden Boat Building

For a Wooden Boat to be successful it needs to be built of timbers joined in such a way that they provided a hollow interior with a water proof outside shell. Either the method of joining the timbers and/or an internal framework must provide structural integrity. The structural integrity must be able to resist both static forces (i.e. the boat must be self supporting both longitudinally and in cross section when at rest) and also must be able to resist the enormous dynamic forces of wave and wind on the hull, superstructure and any rigging.

The following methods of Wooden Boat Building use differing techniques and hull designs to achieve the desired results.

Clinker or Lap Strake Built Boats.

The Clinker or Lap Strake built boat is the type of construction used most beautifully by the Vikings when building their longships. It is an excellent lightweight method of boat building, a method which is most often used today in dinghies and small craft.

In this method the boat is built from longitudinal planks with the bottom edge of one plank overlapping the top edge of the one below. The planks are joined at the overlap with rivets, clenched nails or glue. The overlapping of the planks provides for excellent stiffness and means that internal framing can be kept to a minimum, which creates a light sturdy boat. The method often allows for the hull to be built first and the strengthening internal frame to be fitted afterwards.

Modern Plywood construction of clinker or lap strake hulls often uses resilient, flexible, easily worked marine grade plywood with epoxy being used to bond the planks. The epoxy provides bonding, filling and protection all at once, allowing the speedy building of a vessel which has the beauty and strength of wood and a superb low maintenance finish.

It was not unusual for older clinker boats built of natural timber to need “soaking” in order for the timber joints to swell and so become water tight. This has been eliminated with the use of modern epoxy bonding.

As the size of a Lap Strake boat increases, the thickness of the planking required and the size and weight of the internal bracing grows to an extent that the Carvel Built boat provides a far more efficient use of timber and better structural integrity.

Carvel Built Boats

A Carvel built boat is one in which the internal structural frame of the boat is created first and then the planking is attached. The planking consists of longitudinal timbers which are fitted and attached to the preformed timber frame. They are joined edge to edge, with no overlap (butt joined). The joint between the planks is sealed by caulking or by a specially designed timber fillet inserted in a groove in the edge of the planks.

This is the method which was and still is the most common form of building larger wooden boats and commercial ships. The frame of the boat and timbers required for construction can become quite massive as the size of the vessel increases.

Plywood on Frame

The introduction of Waterproof plywood has seen the development of “ply on frame” and then later even “frameless plywood” boats being designed and successfully produced.  These methods are ideally suited to the amateur or novice builder because they allow for a quick and relatively easy build taking full advantage of modern cheap power tools.

The frame of the boat may be constructed of timbers or may be cut out of plywood sheets, which provides a form of internal bulkhead. The use modern epoxy glues which give waterproof joins which are often much stronger than the timber itself also speeds the building process.

Stitched Plywood

The stich and glue building method where the plywood joints are held together by either wire or plastic ties and the joint is covered with fibreglass and epoxy is a popular modern building method. This has lead to the design of plywood boats which are frameless, relying on the integrity of the bonded hull to provide structural strength.  This means an extremely lightweight hull can be designed.

Cold Moulding

Cold moulding is another modern method taking advantage of the superb characteristics of modern epoxy bonding materials. In this techniques a minimum of two layers of thin strips of timber (usually plywood or veneer are laminated on top of each other. The layers run in different directions, usually in a diagonal pattern. Often insulation is bonded between two outer layers and an additional inner layer. This method requires a preformed mould on which to build the boat and this extra work usually precludes the amateur builder. The method does however produce beautifully lightweight hulls which are very strong.  Often vacuum forming is used to provide an extra fine finish and ensure the close bonding of the timbers. 

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