At sea · 2 min
When a ship needs help
GMDSS brings several communication methods together so distress information can reach the right people.
✓The knowledge library
One idea at a time. Read the essentials, follow a diagram, try a question.
No lessons match. Try another word or clear your filters.
At sea · 2 min
A name beside a moving dot
AIS shares vessel information, but a screen is only as good as the information reaching it.
✓At sea · 2 min
A memory for the voyage
A voyage data recorder preserves information that can help investigators reconstruct an incident.
✓At sea · 2 min
Clarity before eloquence
Standard maritime phrases reduce ambiguity when people with different first languages work together.
✓At sea · 2 min
Two networks, different consequences
IT handles information. OT monitors or controls physical processes. On a vessel, both can affect operations.
✓At sea · 2 min
Why orbit matters at sea
A satellite’s orbit influences distance, apparent motion and how a connection must be maintained.
✓Networks · 2 min
Follow one packet
A network moves small units of data through connected devices. Different devices solve different parts of the journey.
✓Networks · 2 min
Names need directions
DNS helps applications find information associated with a domain name, including IP addresses.
✓Networks · 2 min
Where does this address belong?
A prefix tells us which bits identify an IPv4 network and which bits remain for addresses inside it.
✓Networks · 2 min
An address on loan
DHCP can supply a device with an IP configuration for a limited lease period.
✓Networks · 2 min
Reliable delivery or timely arrival?
TCP and UDP provide different transport building blocks. Applications decide how to use them.
✓Networks · 2 min
Fast is more than a speed test
Bandwidth, delay, variation in delay and packet loss describe different parts of network quality.
✓Security & recovery · 2 min
Keep a way back
Good security considers what happens after a device, account or familiar recovery method is lost.
✓Security & recovery · 2 min
One secret should not open every door
Reusing a password lets a breach at one service create risk at another.
✓Security & recovery · 2 min
More than a password
MFA asks for more than one kind of proof. Passkeys use cryptographic keys tied to a service.
✓Security & recovery · 2 min
Pause before urgency wins
A convincing message can still lead to a false login page or a request you did not expect.
✓Security & recovery · 2 min
A backup earns its name when it restores
A backup is a recoverable copy from another point in time. Synchronisation alone may also copy mistakes.
✓Security & recovery · 2 min
Start with what matters
Risk management starts with what you value, what could happen and how you would respond.
✓Marine electrical · 2 min
Voltage, current, resistance
For an ideal resistor under fixed conditions, Ohm’s law connects three quantities: V = I × R.
✓Marine electrical · 2 min
A direction, or a rhythm
DC flows in one direction; AC reverses direction periodically. The shape and frequency matter to equipment.
✓Marine electrical · 2 min
Watts are not watt-hours
Power is the rate of energy transfer. Energy accumulates over time.
✓Marine electrical · 2 min
Two numbers on the same load
In AC systems, real power in watts and apparent power in volt-amperes are different quantities.
✓Marine electrical · 2 min
Isolate the fault, preserve the rest
Protection coordination aims to clear a fault while limiting unnecessary loss of supply elsewhere.
✓Marine electrical · 2 min
An early warning in the insulation
An insulation monitoring device watches insulation resistance in an unearthed electrical system.
✓Marine electrical · 2 min
A dark screen is not proof of isolation
Equipment can have more than one supply or retain stored energy after normal operation stops.
✓Marine electrical · 2 min
Read the route of power
A simplified single-line drawing helps you see electrical supply relationships before looking at detailed wiring.
✓AI & learning · 2 min
Ask for a guide, then do the thinking
Use AI to ask questions and uncover gaps in understanding, then check the result yourself.
✓AI & learning · 2 min
A fluent answer still needs evidence
AI can produce confident statements, quotations or references that are wrong.
✓AI & learning · 2 min
Make something to understand something
Explaining an idea with a drawing, recording or short video exposes what you do and do not understand.
✓AI & learning · 2 min
Design the question before the app
A prototype lets you test an idea before committing to a complete application.
✓AI & learning · 2 min
Close the page. Recall the idea.
Trying to retrieve an idea from memory is a different learning activity from rereading it.
✓AI & learning · 2 min
Use the summary as a doorway
A short summary helps you begin. Sources let you inspect the evidence and the limits behind it.
✓Beyond the horizon · 2 min
Looking far is looking back
Light takes time to travel. The view of a distant object arrives after the event that produced it.
✓Beyond the horizon · 2 min
A universe with a history
The hot Big Bang model describes an early hot, dense universe that expanded and cooled.
✓Beyond the horizon · 2 min
An ancient glow, everywhere
The cosmic microwave background is relic radiation from when the young universe became transparent to light.
✓Beyond the horizon · 2 min
A star is a balance
A star’s life is shaped by gravity, internal pressure and the energy generated inside it.
✓Beyond the horizon · 2 min
A boundary light cannot cross outward
A black hole has an event horizon: a boundary beyond which light cannot escape to a distant observer.
✓Beyond the horizon · 2 min
The Moon changes its appearance
Moon phases come from the changing view of the Moon’s sunlit half as it orbits Earth.
✓Beyond the horizon · 2 min
Read the light
A spectrum separates light by wavelength, revealing information hidden inside a single bright point.
✓Beyond the horizon · 2 min
What we infer from what we can see
Dark matter is inferred from gravitational effects that visible matter alone does not adequately explain.
✓Security & recovery · 3 min
Three questions for a safer system
Confidentiality, integrity and availability describe different things that can go wrong. On a ship, the consequences may be physical.
✓Security & recovery · 3 min
Know what depends on what
An asset list becomes useful when it records function, ownership and dependencies, not just serial numbers.
✓Security & recovery · 3 min
Separate networks, control the crossings
Crew Internet, office IT and operational systems need deliberate boundaries. A different Wi-Fi name alone does not create one.
✓Security & recovery · 3 min
A small USB can cross a large boundary
A removable drive can move files between networks that are otherwise separate. Its origin and handling matter.
✓Security & recovery · 3 min
A maintenance window should close
Remote support is useful when access has a known person, a specific purpose and a defined end.
✓Security & recovery · 3 min
An update is a controlled change
A security patch may improve protection while changing operational behaviour. OT maintenance needs both security and engineering judgement.
✓Security & recovery · 3 min
The first report can preserve the next choice
A useful first response limits further interaction, protects safe operation and preserves observations for the responsible team.
✓Security & recovery · 3 min
Keep a clean route to recovery
Ransomware may encrypt data and steal it. Recovery needs a trusted source, a controlled environment and a check that the service works.
✓Security & recovery · 3 min
Two screens may share one wrong position
Agreement between displays is not independent confirmation when both depend on the same input.
✓Security & recovery · 3 min
Cyber risk belongs in daily ship management
Cyber risk management connects people, systems and safe operation. It needs responsibilities and exercises as well as technical controls.
✓Security & recovery · 3 min
The ship and the equipment: E26 / E27
IACS E26 considers the ship’s cyber resilience; E27 addresses onboard systems and equipment. Their scopes complement each other.
✓Security & recovery · 3 min
42% is a survey result, not your attack probability
The Allianz Risk Barometer 2026 ranks business concerns. Reading the denominator prevents a striking number from becoming a misleading claim.
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