Marine Plywood

Marine plywood provides greater protection: a small scratch through the resin or glass, if not repaired, may expose the plywood to water. Inexpensive plywood may not last long in that case.

Marine plywood strongly increases the resale value of your boat.

Marine plywood is stronger and has consistent mechanical properties: no voids.

Marine plywood is much nicer and easier to work with.

For small boats, quality 4 mm plywood is a good substitute for the 1/4" exterior ply often specified.

Marine plywood (except for Fir) will not check. That feature may by itself pay for the difference in cost. To get a good finish with Fir or Pine, the hull will require extra fiberglassing and large amounts of fairing compound. This is not necessary with Meranti or Okume.

Marine plywood, on the other hand, is a type of special-purpose plywood. Plywood is a type of manufactured wood panel. It is made by gluing together plywood layers, also called veneers. These veneers are glued together with adjacent plies having their wood grain at right angles to each other. This allows them to form a composite material. Cross-graining, i.e. having the wood grain at right angles to each other, reduces the tendency of wood to split, as well as reduces expansion and shrinkage. It also makes the strength of the panel consistent across both directions.