Did you know you can have a right rotation or left rotation boat propellor

Question

Do you know any other useless facts. (to non-boating people that is)

Answer 1

The prop may also be reversible, and counter rotate to allow a boat to go in reverse, for close manouevering , and there is another form of reverse which exists, ,  (seen on Navy diving tenders), it is the "Patterson" bucket, a semicircular half globe, that is split down the middle, placed or sited over a propellor, the two halves are left open, during forward movement, but closed, they make the water that is forced back, from the propellor, to be forced forward again, thus propelling the boat backward, try cupping your hands and imagine they are over a propellor, now open them and imagine the flow movement from the propellors "wash".

They can also be used for steering when open, ( and when closed, but with less force control, ), if the bucket is rotated, on a vertical axis, to bring one or other of the 1/4 globes nearer to the longitudinal axis of rotation for the propellor, thus obviating the need for a rudder, and giving very sensitive handling characteristics, in tight areas....

I was a regular on the navy diving tender as a young man, and sailed most weekends as crew, often overnighting for three or more days at a time, and steering as a "rudder" man, (even though there was one fitted, it was rarely used for diving operations, work, ), it was much safer when hoses were being used, to control this vessel, with the bucket, ( because the bucket encloses the propellor, making entanglement much less likely ), so I also learned to do this too, nowadays, this method is rarely used out side of this type of vessel, or the navy services around the world, as it has been superceded by "reversible" props, but it is much easier to make than a reversible prop, and easier to maintain, but for some reason, young people do not seem to understand the way it works, nowadays....

Answer 2

Yes, but do you know why? In a twin motor set up it cancels out the tendency to 'walk' the stern one way or the other. R/h one one motor l/h on the other. On a large single motor, contra rotating props (one l/h and one r/h) also cancel out the turning effect on the stern. I thought you would like to know this, as you seem fascinated by trivia.  

Answer 3

I've got a useless fact linked to rotation.

The very first Vauxhall Cavaliers were rear-wheel drive. When moving off in any other car, the back end goes down, on the Mk 1 cavalier, the back went up, this was because the proshaft rotated anti-clockwise which was, and still is, unique to any rear-wheel drive car.