The team considered mimicking this approach with thin GFRP sheets backed with mineral wool, but decided the sheets would be too heavy. Eventually, they opted for a code-compliant core sandwiched between single layers of low-cost, woven glass fibers that are impregnated with a resin that meets IMO fire test requirements for calorific value and flame, smoke and toxicity (FST) properties.
The panels for the prototype cabin were fabricated at PE Composites on the Isle of Wight using large flat tables, vacuum bag processing and conventional oven curing. The walls feature eight panels – two sides, two end walls and four smaller panels that form the cabin’s wardrobe and encompass the “wet unit” (toilet, sink and shower module). The GFRP deck head (ceiling) includes a rectangular recess or ‘coffer’ to hide air conditioning ducts and provide an improved lighting scheme.
Royle says the team spent more time talking about how to affix the panels to each other than anything else. They considered composite extrusions and angles, but decided to use steel angles because the cabins are expected to be assembled in shipyards. “You don’t have laminators in shipyards; you have metal workers,” says Royle. “We recognize that we are trying to move new technology into a metal industry. So the focus was always on what is the easiest possible way to assemble this.” The new cabin also has a steel bottom channel so that it can be welded to the deck like a conventional steel cabin.
After the panels were completed, Trimline assembled them into a 20-foot, 4.1-inch-long, 8-foot 10.2-inch-wide and 7-foot, 2.6-inch-tall cabin – the same dimensions as a typical Carnival balcony cabin. Trimline also outfitted the cabin, including lightweight composite furniture made from the same materials as the cabin. Aside from being significantly lighter, this furniture performs much better in a fire than furniture manufactured from standard materials approved by the International Convention for the Safety of Life at Sea (SOLAS), according to Royle.
Royle and Spooner both emphasize that the composite cabins not only save weight, but also bring significant changes to interior design. Steel cabins have vertical wall seams every two feet, ceiling seams every foot and a thin vinyl film coating that has a wood grain or other common pattern. The result, Royle says, is unattractive and “the same the world over.” In contrast, he says, the composite walls are seamless and can be painted, providing the freedom to create “a cabin that looks like no other.”