Bureaucrat, staff, administrator
4,335
edits
Changes
m
→Mechanical V-Drive
In a constant-velocity (CV) anti-vibration system such as the AquaDrive®,<ref>AquaDrive, http://www.aquadriveusa.com/advantage/advantage.htm</ref> there is a propeller shaft and a separate drive shaft, coupled with a CV joint. The propeller shaft ends in a [[ThrustBearing|thrust bearing]] mounted to the hull.
[[File:AquaDrive.jpg|thumb|250px|left|Standard mechanical drive (top) compared to AquaDrive® using intermediate thrust bearing and CV joints
– Graphic with permission © Aquadrive, http://www.aquadriveusa.com/]]
This bearing takes the end-thrust from the propeller and transmits it to the hull to move it through the water. The drive shaft has a CV joint at both ends, and is splined inside so that its length is adjustable. This allows the engine to be mounted on flexible rubber mounts.
=== Mechanical V-Drive ===
[[File:BorgWarnerVDrive.jpg|thumb|250px|left|Borg Warner V-drive
– Graphic with permission © Trans Atlantic Diesel, http://www.tadiesels.com/borg_warner-vdrive.html/]]
A mechanical V-drive is a compact reduction-gear transmission that reverses the direction of the drive shaft. It allows the engine to be placed aft, facing aft, with the output shaft facing forward. The V-drive reverses the direction of the output to connect to the propeller shaft, usually at an angle of 10-15 degrees. Typical manufacturers are: Borg Warner, Halibrand, Twin Disc Marine Transmis-sions, Yanmar, and ZF.
=== Continuously Variable Transmission ===
[https://en.wikipedia.org/wiki/Continuously_variable_transmission#Hydrostatic_CVTs Continuously Variable Transmissions ] (CVT) are mentioned here only for completeness. A CVT has a nearly infinite range of gear ratios. Like a controllable-pitch propeller, a CVT allows the engine to operate at its optimum rpm regardless of the speed. Until recently, CVTs were too expensive and unreliable for use in cars; although hydrostatic types have been used in main battle tanks. They are unlikely to be adapted for marine use.
== References ==
