#propeller cap

Homestar shows his propeller cap.

Because of its almost uniform effectiveness in both full-load and ballasted conditions, the propeller cap turbine (PCT) is generally the most cost-beneficial. It is easily designed for retro-fit and the relatively low cost can be recovered quickly. By installing a properly designed PCT, with varying pitch of air-foiled shaped blades integrally cast into the hub cap, energy from the rotating fluid coming off the propeller hub is recovered by these small shaped blades, and hence energy savings is achieved over a wide-operating range of ship speed and draft/trim conditions. A device similar to the PCT, but proven to be less-efficient and more-expensive in competition, is called the PBCF (Propeller Boss Cap Fin) which utilizes only flatplates. To properly design an efficient PCT, technical information is needed about the ship as listed under Engineering Input.Because open-water propeller tests should be conducted to design the PCT, time to manufacture the PCT is about 5 months. Sea shipment from Shanghai to any location worldwide can be done in less than 6 weeks. In addition, air freight can be arranged as an alternative to sea transport in urgent delivery situations. Large units for 40,000 to 60,000 HP propellers weigh in the region of 2500kg and are somewhat less than one-third of the propeller diameter, or about 2.500 meters.Because weight of the PCT represents only about 1 to 2% of the propeller weight and propeller torque is reduced about 3 to 5%, there appears to be only a very small influence of the PCT on engine RPM and shaft torsional vibration. However, for a reasonable fee, calculations can be provided, but has not been required by classification society in previous applications, to quantify the expected influence. Also note this torque reductioncan provide a benefit to diesel propulsion engines that are operating in a heavily loaded condition.Significant cost-benefit can be gained from application of the PCT to propellers on all type of ships: tankers, bulk carriers, and container ships. Even ships with controllable-pitch propellers have been fitted with PCT’s

Warehouse Graffiti Haven Part 63