Propulsion Experiments with a Tunnel Hull Planing Craft to Determine Optimum Longitudinal Placement of Propellers and Effects of Nozzle Sideplates in the Tunnels

摘要

This report consists of an experimental evaluation of tunnel hull configurations on a planing hull model and determination of the optimum longitudinal placement of the propeller in an existing tunnel design. Resistance, self-propulsion, and draft data are presented for Model 5048 fitted with twin tunnels which have a depth of 40 percent of the tunnel diameter. Effects of propeller tip clearance and nozzle sideplates installed in the tunnels were also investigated. The longitudinal placement of the propeller inside the tunnel had a small effect on powering and draft with the forward location having slightly less delivered power than the aft locations. The addition of nozzle sideplates significantly reduced the draft, running trim and propulsive coefficient at high speeds. However, the nozzle sideplates significantly increased the resistance and delivered power. (Author)