Why are trucks and planes controlled from the front, but most big ships controlled from the back?


Why are trucks and planes controlled from the front, but most big ships controlled from the back?

In: Engineering

Many modern ships have aft accommodations because it simplifies construction. The accommodation is the big structure that contains the sleeping cabins, the galley, the bridge, etc. Under the accommodation, is the engine room casing. It is a cheaper and easier construction to place the accommodation directly on top of the engine room casing. You don’t need to build additional bulkheads, thus cutting down on weight. Less ship weight means more cargo.

If the engine room casing and accommodations are places forward of the ship instead of aft, then you need to construct a long shaft that goes from all the way forward to aft. This shaft connects the engine to the propeller. By building a shaft, you add more weight to the ship, take away room (a shaft needs a shaft tunnel) and you increase the amount of moving parts which need to be maintained.

Even if you want to use a long shaft, you would still need an aft compartment for certain pieces of machinery. Many ships use a CPP (controllable pitch propeller). This is a hydraulic setup which changes the pitch (angle) of the propeller blades to adjust the speed of the ship, and you can also make the ship go astern. You would also need a steering flat, which is a hydraulic pump setup which turns the rudder. According to regulations, you need bulkheads at the aft, forward, and in front and aft of the engine room casing. With an aft house, the aft bulkhead and the aft casing bulkhead can be the same one, meaning you need one less bulk head. With an engine not aft, you need that extra bulkhead. So, even if you have a forward engine room, you would still need a lot of machinery aft.

There is also a safety consideration. Ships have a limited amount of engineers, sometimes there aren’t any on watch at the time. Should something happen, like a steering failure, it could take a long time for an engineer to make it all the way back aft to the steering flat and activate the emergency steering mode. In an after accommodation ship, you only need to go down the stairs.

As for maneuvering and navigation, there may not be a definite advantage. Many of the older ships on the Great Lakes had forward wheelhouses. The guys that sailed most of their time on them swear by them and claim that is the best way to sail. Myself, I have never been on a front end job and don’t see any positives. There might be an objectively better setup, but then it might come down to preference.

It may be hard to see the path in front of you if you are stuck behind the cargo compartment. But if you sit in front of the vehicle you do not see the sides for when you are turning. So in all of the vehicle types you mention the operator sits as far back as possible while still being able to see in front of him. For example on a cruise ship the bridge is at the front. However on an agricultural tractor the drivers seat is often right over the rear axle. A lot of sports cars put the drivers seat close to the center of the car or even a bit behind the center. Some planes now have taxi cameras mounted at the tail allowing the pilot to taxi from the vantage point of the tail instead of only looking out the cockpit windows in the front. Cargo ships is different from cruise ships as cargo is heavier then the mostly empty space of a cruise ship. And because the weight of a ship equals its displacement you can not stack containers as high as a cruise ship so you can mount the bridge further back so you can see over the containers and still boats and docks on the side of the ship.