“For this giant piece, we had to penetrate the PVC foam core cell and e-glass fiber laminate over long distances. We needed very efficient saturation,” notes Pierre Lallemand, chief of the composite department at H2X. “It was a huge risk, but we decided to use a vacuum bag infusion process for the entire main hull in one shot.” According to Lallemand, the Ocean Eagle 43’s hull is one of the largest sandwich epoxy hulls ever made in a one-shot infusion. It required more than 4,000 kilograms of epoxy resin. “There’s no room for error in this decision,” says Bertrand Fergelot, sales manager with H2X. “If it is not done well, all the work you have done to prepare goes down the drain.”
Lallemand says vacuum infusion allowed for better saturation of the core. “We were better able to control the amount of epoxy used for the part, resulting in very tight control of part weight,” he says. Vacuum bagging also mitigated emissions exposure for workers.
Sicomin supplied H2X with SR8100, a two-component epoxy system, for the hull infusions. The injection process took four hours, followed by four hours to ensure the glass fiber lamination was saturated. Afterward, the hull was post-cured for 16 hours in a 43-meter oven at 50 C to 60 C.
The result? “We were able to deliver the main hull within 0.3 percent of the estimated weight,” says Lallemand. “This would have been impossible to achieve if the hull was made by hand.”
Fleet Ready, Fishing Bound
The marine industry is calling for more aggressive lightweighting and cost-effective designs, and among those leading the charge is the U.S. Navy. “It’s a constant battle to optimize boat weight to maintain stability, yet design it to afford more people and equipment on board,” says Urich Gottschling, president and CEO of Willard Marine, a manufacturer of composite watercraft for the U.S. Navy for more than 30 years.
Willard Marine and Structural Composites, a composites technology company that holds a Small Business Innovation Research (SBIR) contract, have designed, constructed and tested the 7M Fleet Ready (7MFR) rigid inflatable boat, a next-generation advanced combatant craft for the U.S. Navy. The goal was to provide the Navy a boat design with the durability and maintainability of solid laminate construction at a weight equal to sandwich construction, with cost reduction in mind.