HOW DOES A SHIP MOVE?
The Adventuress as an Engineering Masterpiece
Table of Contents
Interested in engineers? Take a look at: What do engineers do?
Interested in engines? Take a look at: How does a ship move?
Interested in the ship's electricity? Take a look at: How is a ship powered?
Interested in ship structure? Take a look at: An Introduction: The Rudder and The Keel
This is Bosun's Locker! The senior officer of the deck crew, known as the Boatswain, or Bosun, is charged with regularly inspecting and maintaining the ship hull and deck. And for all that, they sure don't have a lot of space to keep tools!
What do engineers do?
Engineering is a broad field, but there are two main aspects that make up most of the work: solving problems and preventing problems. This is no different when it comes to engineers that work on the Adventuress.
As you can probably imagine, the Adventuress is a unique system to work on for multiple reasons. One is that it lives on the water, so the whole structure and weight of the Adventuress itself must be well thought-out and constantly maintained to prevent itself from sinking. This unique structure is also difficult to work in, since the confined space of the ship means engineers have to work without the help of large machines and cannot access everything very easily.
The other is that the Adventuress is a portable and moving vessel. This means that it must be able to sustain itself for periods at a time without connection to a power supply grid or water supply.
When it comes to daily work, an Adventuress engineer can find themselves all over the ship. When plans require complex pieces of machinery like the engine or generator to work safely and properly, engineers must be checking at every point to ensure that things are running smoothly, and be ready to alert someone and shut down operations should anything be out of the ordinary. Afterward, it is also the engineer's job to find the source of the issue and figure out what needs to be done to address it. All along the way, the engineer acts in close partnership with the captain, giving reports and updates with their many different checklists.
Engineer have many other jobs like...
operating maintenance machines (pumping out bilges, which are a collection of seawater that trickles into a ship through cracks and seams)
ensuring that systems that aren't used too often still work (emergency water pumps, shutoff switches and valves)
cleaning up (oil absorbing, lubing, tracking any spills)
monitoring all systems, tracking issues, and finding solutions
To learn more, click below!
Engineer Angi, right
Engineer Drew
Engineer Gray
Want to learn more about ship maintenance?
Between these important events, engineers must also go through routine maintenance and monitoring of each system that needs to function, no matter how often it will get used. There are a lot of things that must be looked at:
fuel levels: checking fuel levels are called "fuel soundings". Just like making sure a car doesn't run out of gas on a trip, a ship's fuel must be monitored often so that refuelings can be scheduled.
white water levels: In plumbing, "white water" is the term for clean, drinkable water. Making sure that there is enough white water stored on the ship is important for the crew's sanitation and health, and refilling water levels must also happen when docked.
yellow (pee), grey (sink drainage), and black (poop) water levels: As much as the Adventuress intakes water, it must also get rid of it. The ship's tanks must be watched so that they can be pumped out far from shore or at a designated site before overflowing.
bilge levels: while sometimes program participants (possibly such as yourself!) help monitor the bilges, engineers are charged not only with checking the bilge levels, but also cleaning up any oil that may have made it's way there before operating the pumps to empty them out.
battery voltages: there are an array of batteries that hold charge to power different systems, and they must be charged while the engine or generator is running, and monitored for their overall health.
Engineers keep many schedules running. On top of these daily tasks, they must also flush the heads (bathrooms), clean the stoves, clean batteries and refill some with water, clean out water strainers, and test various alarms and emergency equipment. Maintenance of engines often require checking various oil and coolant levels, lubricating any moving parts, looking for any dripping and cleaning out the pans that catch any dripping, and inspecting any belts or gears for wear and tear. Smaller systems, such as the refrigerator and the stoves in the galley (which you can read more about on the Galley Stop on our tour), must also be periodically taken a look at. All of these tasks are aimed at lengthening the life of any expensive or important equipment and making sure they run as efficiently as possible.
How does a ship move?
Yes, the Adventuress can use sails to travel long distances, but when captains need precise control in a small area, they rely on motors and engines.
A ship engine is in many ways, similar to a car engine. It's main principle is to take the potential energy stored in the chemical bonds of a fuel source (diesel for this particular engine), and mix it with air and compress at a high pressure to cause it to explode (kinetic energy and heat), which pushes a piston. This piston rotates a shaft (mechanical energy), which would be connected to a transmission and ultimately to the wheels of a car, or to a propeller on the back of a ship.
Adventuress' Traditional Engine Before Exchange
above: Engine Before Installation, Susan Brittain
below: 6.8L John Deere Heat Exchange Engine Models, John Deere Manuals
Here are some interesting specifics about the engine:
The Adventuress has a diesel engine: diesel engines are more efficient than gasoline engines because more of the heat is turned into mechanical work with more power. Why is this important? Well, this means that the engine can spin at a much slower speed while still maintaining the same torque. Slower moving parts means that the engine can last for longer.
The Adventuress uses diesel fuel: diesel is refined differently from gasoline and is more energy dense because it has more long-chain hydrocarbons (bonds with energy!).
The main engine has six cylinders while a car will normally have four.
The Adventuress' engine is cooled with sea water which comes in on the port side. This is why you will sometimes see water dropping out of the side of the ship- it's carrying heat away from the engine!
Ever wonder how turning a propeller moves an entire ship forward?
The blades of a propeller each look similar to plane wings, just curved. Plane wings have an interesting shape: they are smooth on top to allow air to move quickly over it, while angled on the bottom to slow down air flow. Slower air creates a higher pressure than faster air, so the higher pressure beneath the wing pushes the plane up.
A propeller makes use of the same concept, creating a difference in pressure backwards-forwards (instead of up-down) by increasing the water's movement in front, lowering the pressure in front of the propeller. The higher pressure behind the propeller moves it forward through the water.
Did You Know?
A transmission in a car might say, "Drive", "Neutral", and "Reverse",
but the Adventuress' says "Ahead", "Neutral", and "Astern" (the stern of a ship is the back or rear side!)
How is a ship powered?
Now, you may think of "electricity" in your daily life as a resource that comes from an outlet to power things like lights or phones. For houses and buildings in city areas, electricity is easy to obtain simply by plugging in to the city's power grid. However, ships like the Adventuress can't have a cord connecting it to land at all times. This means that it must be able to either generate it's own electricity on board, or store electricity that it can take in when docked.
Ship Electrical System, Simplified, Ellie Chew
The Adventuress can get power from a variety of sources. There are multiple batteries on board, one specifically for the console (interface to control the boat) and two for general use. However, the ship can also switch to shore power input, running it through inverters to match the current and voltage of the internal system. Finally, the ship also has a generator that turns fuel into electrical energy in a similar way to an engine. These three power input sources are labeled in the diagram in pink.
The electrical system of the Adventuress is complex because it must balance both DC and AC current. DC current is used for various pumps, alarms, fans, and lights as well as for important navigation equipment like radars, GPS's, depth sounders, and the console. AC current is used for the common lights, outlets, and refrigerator. To change from one type of current to the other requires inverters. Additionally, the engineer must aid in the control of what sources the electricity from where, taking note not to drain batteries when disconnected to shore power.
Adventuress Side Plan, Labeled
An Introduction: The Rudder
and The Keel
How do ships turn?
Turning a boat is a little different than turning a car. When turning a car, you can change the direction the car is moving in by changing the speed and direction of the wheels that are touching the ground. Because a ship is not in contact with the ground, it must use an understanding of water physics to change it's direction.
An important piece of the puzzle is the rudder. It is easiest to think of the rudder as a large door that is stuck behind the propeller on the stern (back) of the ship. The rudder is controlled by the ship's steering wheel (which is why the steering wheel is so far aft). When the wheel is turned towards port, the giant door turns towards port as well, and so forth. The complicated term for it is a "hydrofoil", which hints at it's similarity to "airfoils" like wings, sails, or propellers.
Modern Ship Rudder, Wikipedia, Labeled
Propeller and Rudder Labeled on
the Adventuress
The Adventuress Drydocked, 2021 (Can you spot the rudder?)
However, the rudder cannot do all the work itself. A rudder would have to be very structurally strong and very large in order to push a whole boat on it's own. So instead, a regular rudder will usually just send the boat into a slight drift angle. The rest of the work is done by the hull. (This is why it takes a bit of time for the ship to "respond" to someone turning the steering wheel! Turning is a multi-step process.)
When a ship is turned slightly sideways, the hull on the outside is suddenly pushing against a lot of water, battling against the unwillingness of water to move, the "inertia" of water. The shape of the boat is made specifically so that when this happens, the hull in the front will be pushed against a lot more than the hull in the back. The force of the water pushing on the front helps the force of the rudder on the back to complete the turn.
Now, the rudder must return straightforward to stop the ship from turning. This increases the force of the water pushing on the back of the ship to equal how much it is pushing on the front of the ship, and balances forces so it moves in a straight line again.
One thing to note is that a rudder is not a source of power. If a ship is not moving forward, the rudder will have no impact on it's direction, like turning the wheels of a car while it's sitting still. This also means that the faster the ship is moving, the more quickly and powerfully the rudder can turn the boat.
This was a huge oversimplification of how rudders and ship turning work. There are a ton of different types of rudders and different shapes of ships to deal with the complexity of fluid dynamics!
Why don't ships flip upside down?
Take a look at a sailboat and you will probably marvel over how tall the sails are. When they are filled with wind pushing sideways, how come the ships don't tip over?
That's because there is a countering force on the bottom side of the ship called the keel. It looks like a fin sticking out of the bottom of the hull, with varying sizes... some can take the entire length of the ship! It's often made of the same material of the ship, which for the Adventuress is wood!
The keel acts as a stabilizer: because it's aligned with the ship, it doesn't add drag when the ship is moving forward. But if a strong wind threatens to push the ship sideways, the keel pushes the opposite way. This is because its large surface area is being pushed on both sides by water, creating a strong pressure force. In other words, it takes advantage of the resistance of water from moving, or inertia. Additionally, there might be an added weight called the ballast attached to the bottom to help the keel stay upright.
For a large ship like the Adventuress, the keel was probably the first part of the ship to be made, with the hull being built around it. This ensures that the keel can survive the magnitude of forces it will face, especially on rough seas. This is also why people often call the keel "the backbone" of the ship.
Fin keels aren't the only types of keel to exist. There are all kinds of differently shaped keels, each usually made to accommodate different types of boating. There is the bilge keel, bulb keel, and wing keel to name a few. The type of keel a ship has determines how large of an angle the ship can recover from when pushed before capsizing. This angle is called the Angle of Vanishing Stability. If you would like to learn more, click here!
Created by Ellie Chew, 2022, as part of a Science Communication Internship.
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