eli5: Why is a ship’s steering at the back and not at the front like cars?


eli5: Why is a ship’s steering at the back and not at the front like cars?

In: 5

I think it is because the turning-torque thingy is in the back instead of the front (eg. A car’s front wheels).

A ships steering is much more efficient if it is behind the propeller, since the water current is much higher behind the propeller. Since the prop is in the back, so is the steering.


Cars have their steering in the front because the steered end is the end that swings out when you steer, so you want good visibility of that end, and car drivers are sitting in the front

There’s some tradition and exceptions to the rule which I can elaborate on later.

But the simplest answer is because in a car, the steering mechanism is at the front, while in a boat the steering mechanism is at the back. Mechanically, keeping the driver close to the steering mechanism has benefits (smaller mechanism, lower weight, less of a problem to extend steering to wherever they are sitting). And for the driver, being as close as possible to the point of turn makes spatially understanding driving s lot easier.

In a car, the front wheels turn to turn the whole car.

In a boat, the rudder (which is what does the turning) sits in the back of the boat at the bottom. You could design a way to transfer the power of the steering wheel from the front of the boat to the back, but this is a larger engineering challenge and could mean cutting back on usable space inside the boat. The easier solution is to put it in the back.

There are lots of reasons, primarily by having the rudder behind the rudder behind the propeller it’s more effective, it also means the hull can be designed to optimise the flow over the rudder, this isn’t possible at the front. Being at the rear make it lees vulnerable to collision which is a fair consideration (especially if it’s me sailing)

For cars it’s different because the friction is far higher, steering at the rear means there’s a far greater imbalance of forces which causes all sorts of issues and would make for a horrible ride.

It’s not particularly eli5 but have a read of https://www.marineinsight.com/naval-architecture/rudder-ship-turning/?amp for boats

https://www.oponeo.co.uk/blog/steering-systems-understanding-the-forces-of-front-wheel-turning for cars

E:forgot about cars – added

Aside from the comments you have on the rudder placement, think about driving a car in reverse. The vehicle is highly responsive. Imagine that level of response but driving forward – it’s far too responsive to drive at high speed with only rear wheel steer.

Rear wheel steer is used on certain cars and heavy duty vehicles, but tends to be to stabilise the vehicle at higher speeds, and reduce turning circle at lower speeds.