Re: why are boats driven from the right side?
<sigh> I've posted this before, but will do so again...
Helm is not on the right because of prop rotation, it is the other way around... prop rotates that way because helm IS on the right. See below:
Modern boat design, like many things, has its roots based on history.
Back in the old days, before powerboats, the captain steered his sailboat (or rowboat, such as Vikings longboats) from the right side, as most folks are predominantly right-handed. The captain also navigated from this helm position, often using his sextant to gauge the stars at night. Thus, the right-hand side of the boat became known as the "steering board", and later as "starboard".
Since the helm was positioned on the right-hand side of the boat, this left the left-hand side of the boat with an empty space in which to carry cargo. The boat would arrive at port with that side of the boat to the dock so that cargo could be easily loaded/unloaded. Thus, the left-hand side of the boat became known as "port".
As boats became more numerous, there arose the need for traffic rules. Since the captain/helm was on the starboard side, maritime rules were developed to take advantage of this fact. Hence, the captain is able to see other boats on his right and is able to "give way", whereas with highly-stacked cargo on the port side, a captain may not see boats on his port side, so he has the "right-of-way". Green and red lighting then followed suit in this manner. These rules also formed the basis for land-based traffic rules which came much later. This is why you "give way" or "yield" to the person on your right (right-of-way) when you meet at right angles at an unmarked intersection in your car/truck.
Later, as motorboats came into existance, the engineers, realizing that in an empty boat most of the weight is concentrated at the helm (starboard side), designed props to rotate in a clockwise fashion (when viewed from the rear of the boat), so that prop torque would be somewhat cancelled by the weight of the helm. As you know, or at least now realize, counter-clockwise rotating props were/are designed to counteract prop torque in twin-engine setups.
Now, why were there LH-steering boats? These became popular after WWII, when the country (USA, that is) prospered, people had money, and manufacturers wanted to get people into boats. The easiest way, they figured, was to configure the boat much like an automobile, so that new boaters would not be intimidated. A typical case where marketing dominated over "form follows function", and resulted in boats that likely performed below what they optimally could have. Also, in the case of jet boats, there was practically no prop torque to contend with.
) In my 1946 MG TC, the gearshift lever is on my left, right hand drive...
