Modular floating dock systems imported in sections are typically entered as the complete article if all sections arrive under a single commercial transaction and are designed to function together. If sections arrive in multiple shipments, each shipment may require a separate entry, and the importer should consider whether the components qualify for duty-free treatment as parts of a larger structure or must be classified individually. A licensed customs broker can advise on the appropriate entry strategy and valuation methodology.

The key distinction is that SITC 79399 structures are not designed for navigation and do not have a specialized primary function (such as dredging, drilling, or firefighting) that would place them in a more specific heading. A floating dock, mooring buoy, or pontoon platform that simply floats and provides a stable surface or anchorage point — without propulsion or a defined work function — belongs here. Any navigability or specialized operational role shifts classification to a more specific SITC heading.