Handling Under Power


Propwalk and Propwash Propwalk and propwash are often confused.


Propwash


The water that comes out of the propeller when in gear is designed to propel the vessel either forward or in reverse. The flow of this water is known as propwash.


In some cases, vessels are designed so that the relative angle of the propeller can be moved.


Alternatively, the wash from the propeller can be directed across the rudder, which then helps steer the boat. The faster the rudder spins, the greater the


effect, but beware of building boat speed. Some vessels will only be able to use the rudder once they are moving and there is laminar flow over it.


Propwalk


Propwalk mainly occurs at slow speeds and is often much more noticeable in reverse. It is a combination of the propeller’s paddle- wheel effect pulling the vessel sideways and the wash from the propeller hitting the boat’s underside, then going out to the side, increasing the movement force.


Propwalk is mainly apparent in vessels with a shaft. The larger the propeller, the greater the paddle-wheel effect.


Propwalk effect is normally greater in astern. 29


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