How to Build a Composite Boat: Part V

Sandwich or Single Skin?

As laminate design progresses, one of the most important engineering decisions is determining where to use sandwich construction and where a single skin laminate is the better choice. There is no universal answer—the optimal solution depends on the structural demands of each area of the vessel.

Sandwich laminates, typically incorporating a PVC foam core between composite skins, provide an exceptional stiffness-to-weight ratio and are therefore widely used in hulls, decks, and superstructures where reducing weight while maintaining rigidity is a key design objective. Their benefits include increased panel stiffness with minimal weight increase, improved thermal and acoustic insulation, and greater overall structural efficiency.

However, sandwich construction is not always the most suitable solution. Areas subjected to high concentrated loads, repeated mechanical stresses, or significant impact require careful evaluation, as the potential for core crushing, localized damage, or skin-to-core delamination can become a critical design consideration. For this reason, single skin laminates are often preferred for keel and machinery foundations, highly loaded attachment points, impact-prone regions, and local reinforcement areas where maximum robustness is required.

Although heavier, single skin laminates can provide greater durability in these applications while eliminating the risk of core-related failures. The objective is not to maximize the use of one structural solution over the other, but to apply each material system where it performs best.

At MIMTec Yacht Engineering, we support shipyards by developing optimized laminate configurations that strategically combine sandwich and single skin structures, achieving the right balance between weight, strength, durability, and manufacturability. In composite boatbuilding, efficient structures are built by placing the right material in the right place.