After custom composites fabricator GMT Composites (Bristol, R.I., U.S.A.) completed a carbon composite passerelle (foot bridge) and a lifting deck and transom for a custom 90-ft ketch under construction in Rockport, Maine, U.S.A., the impressed customer requested that GMT custom build a folding swim ladder to match the boat's general design and character, as an alternative to the commercially available metal ladders. GMT responded with a six-footer featuring a unique combination of teak wood (used elsewhere on the boat) and carbon fiber prepreg.
The ladder's vertical supports are composite tubes that were hand wrapped over an aluminum mandrel with unidirectional carbon-fiber tape prepreg and biaxial twill prepreg, both impregnated with a WEST SYSTEM epoxy resin from Gougeon Bros. (Bay City, Mich., U.S.A.) and supplied to GMT by Newport Adhesives and Composites (Irvine, Calif, U.S.A.). The 1.5-inch (O.D.) rolled tubes were vacuum bagged and oven-cured in a ramped, one-hour cycle at 121°C/250°F. The step treads are laminates of cocured alternating layers of teak and uni carbon prepreg, each shaped, post-cure, by hand, according to GMT's Will Rogers. Each tread features three slots milled with a 5-axis CNC machine. All components are finished with clear polyurethane for seawater protection and to give the ladder a high-luster finish. End caps, hinges and "dogs" (deck fittings) are stainless steel. Weighing in at only 12 lb, the ladder concept is now a regular GMT product offering, which can be built (and priced) to match owner requirements.