Bowthruster Buoyancy Impact

I’m considering adding a small bow thruster to my Freedom 33 cat ketch. In addition to the weight of the unit and tunnel I’m wondering if the water in the tunnel reduces buoyancy by the weight of the water given the volume of the tunnel or if I have to double that as if I was carrying that much seawater in a tank on the boat?

Howdy Alan:

The change in buoyancy will be equal to the volume of the water.Change in trim includes this volume reduction and the weight of the thruster and associated wiring, battery, etc.

Posted by Steve Dashew  (September 17, 2011)

One Response to “Bowthruster Buoyancy Impact”

  1. Donn Taum Says:

    If you want the thruster for docking, I have a solution for under $100: a spring line and a boathook, and learn how to use them.