has been created by a market that fails to intervene. Aimed to correct market and
government failures and induce desired behavior, a voluntary policy option that requests
new technology and routine maintenance, coupled with a tax incentive, would allow ship
owners and the industry to choose how to balance their activity and their tax payments.
Some “quiet ship” propeller technology could enhance the efficiency of vessel
operation and fuel consumption. For example, a propeller fitted into a nozzle not only
reduces radiated noise, but also protects the propeller, directs thrust, and increases
maneuverability (Table 5). Similar to combining the technology of the masker and a kort
nozzle (Table 5), radiated noise might further be reduced by fitting a propeller into a
nozzle while shooting a stream of air bubbles into the propeller (Jasny 1999).
Technology like the highly skewed propeller, combined with proper and regular
maintenance, further reduces underwater noise generated from propeller cavitation
(Fischer and Boroditsky 2001; Table 5). This kind of technology also results in more
efficient vessel operation and fuel consumption (Table 5).