The grid utilizes a box shape to provide excellent bottom support and resist bottom twisting. Its large, flat top surface is also designed to provide excellent support for the floor. Stainless steel screws hold the floor to the grid until the glass cures. Coating the underside of the floor with resin allows the liquid to absorb into the plywood. When the floor glass has cured, holes are drilled for the foaming operation.
Polyurethane foam is pre-mixed and pumped into the grid structure and surrounding cavities.
By carefully controlling foam volume, temperature and density, all voids below the floor are filled. Foaming effectiveness was confirmed when Underwriter's Laboratories tested a production hull by drilling 28 holes through the floor, into the foamed chambers, and submerging the hull for 18 hours. It required 12,600 lbs. U.L. observed that there were surprisingly few air bubbles that surfaced, attesting to the hulls' foaming thoroughness. Upon completion of the 18-hour soak test, the hull was brought to the surface by removing some of the test weights.