Elliott Bay Design Group (EBDG) has completed a hull optimization project for Avalon Freight Services (AFS) to improve the directional stability of their landing craft, Catalina Provider.
Multiple keel designs were considered as viable options for the 150-foot landing craft, and EBDG conducted a computational fluid dynamics (CFD) analysis to estimate the effects each keel arrangement would have on directional stability and overall vessel performance as well as the effect the keels would have on the vessel’s low-speed maneuverability. After the analysis was concluded and the results studied, EBDG recommended moving forward with 18″ deep by 30′ long keels located on the vessel’s chine.
EBDG developed a fabrication and installation drawing to guide the selected shipyard, Al Larson Boat Shop, with the keel additions, and the Catalina Provider is now back in service.
As reported by the Captain of the Catalina Provider and management at AFS, overall vessel performance has improved with the addition of the new keels. Specifically, while transiting to Catalina, the vessel’s tracking has significantly improved, resulting in considerably less required rudder angle. This reduction is creating less vibration and stress on the rudder bearings, thereby extending their life. The vessel has also gained a half-knot of speed with an expected improvement in fuel economy and preferred low-speed maneuverability characteristics.