Specialisation Practitioner → Specialist
Added Weather Resistance
What the weather costs a ship, term by term (wind, waves, current and the water itself), computed to a standard someone else can check.
- Courses
- 4
- Lessons
- 27
- Time
- About 5 hours
- Price
- €489+ VAT
- Assumed knowledge
- Our course Ship Resistance Fundamentals, which builds the calm-water floor every term here is measured against. Vectors, a cosine, square and cube laws, and a calculator for roots and logarithms are all the mathematics required.
€489 + VAT for the sequence
The 4 paid courses cost €646 bought one at a time; as a specialisation they are €489, a saving of €157 (24%).
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You own this specialisation. Every course in it is open to you.
A calm-water speed-power curve describes a ship that does not exist. Every real voyage happens in wind, in a seaway, and over moving water, and the gap between the curve and the measurement is where every performance argument lives. This sequence takes that gap apart term by term: the aerodynamic force on the superstructure; the hydrodynamic penalty of a seaway; the current, which in a uniform stream adds no resistance at all but moves the speed a ship is judged against; and the water itself, whose temperature and salinity move the resistance, and the shaft power with it, by about a per cent, one-signed on a given trade. It is the correction chain that sea trials, performance monitoring and weather routing all depend on, taught so that you can compute each term, state its uncertainty, and defend the total.
What you'll learn
- Compute a wind correction from a ship's above-water geometry, and state which of its eight inputs move with draught
- Explain the two mechanisms of added resistance in waves, and why a sea state given only as significant wave height underdetermines the answer
- Assemble a real seaway from windsea and swell rather than treating it as one regular wave
- Explain why a uniform current adds no resistance, and compute what it does instead through the speed reference
- Spot the three confusions that quietly ruin weather corrections: a current named by where it sets towards, read as if it came from there like the wind and the sea; a true wind used where the hull feels the apparent one; and a speed over ground used where the speed through the water belongs
- Compute the density and viscosity corrections the water itself adds, and explain why a term of about a per cent of shaft power still corrupts a performance trend
- Attach an honest uncertainty to each weather term, rank what drives it, and state the provenance that makes the figure defensible
The sequence
Each course stands alone; this order is the order the knowledge builds.
How the courses build on each other
The order is chosen so each course teaches a different kind of thinking. Added Resistance from Wind comes first because it is the term you can compute from a drawing: an area, a dynamic pressure and a coefficient, with the apparent-wind vector and the still-air subtraction as the two steps that decide whether the number is right. Added resistance in waves is the hardest number in ship performance and gets two courses: Part 1 builds the physics and the honest description of the sea, Part 2 builds the working method (the SNNM regression, the spectral machinery, real seaways as windsea plus swell, and what a validation does and does not promise). Currents and Water Properties comes last on purpose: in a uniform stream the current is not a force at all, and appreciating why takes a reader who already knows what a genuine added-resistance term looks like. It then prices what a stream does cost a ship holding her track across it, and ends on the water itself, whose density and viscosity are corrected for rather than filtered. Two topics recur by design: the relative-heading arithmetic appears throughout because every weather term needs it, and the ship's own velocity enters twice, added to the wind for the apparent wind and to the current for the speed through the water, while the direction convention flips between them (wind and waves are named by where they come from, a current by where it sets towards). The calm-water components themselves are not re-taught: Ship Resistance Fundamentals owns them and is cited rather than repeated.
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Paid Specialist
Added Resistance from Wind
The one added-resistance term you can compute from a ship's drawing, taught end to end: apparent wind, the coefficient that turns a superstructure into a force, the subtraction that makes it 'added', the Fujiwara regression and its traps, and what the number is worth once the anemometer has had its say.
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Paid Specialist
Added Resistance in Waves, Part 1: The Physics and the Sea
The foundations the hardest number in ship performance stands on: the two mechanisms that generate it, how one hull answers each wavelength, what a wave spectrum really says, where wave data actually comes from, and the three families of method that turn a sea state into a force.
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Paid Specialist
Added Resistance in Waves, Part 2: The Method in Practice
From physics to a defensible number: the SNNM method and how it earned regulatory standing, the spectral assembly that closes the 'which wave period' problem, real seaways as windsea plus swell evaluated as separate systems, what validation does and does not promise, and how the number is spent in trials, monitoring, routing and claims.
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Paid Practitioner
Currents and Water Properties
The weather term that, in a uniform stream, is not a force: what a current actually does to a ship, why it changes required power without adding resistance, how it disguises itself as hull degradation, and what the water itself, its density and viscosity, genuinely does add.
The specialisation certificate
Every course above ends in a graded final exam and a certificate. Hold the certificate for every course, and a capstone project unlocks: one scenario that draws on the whole sequence, marked on our server. Pass it and you get a second, separate certificate for the specialisation itself, naming every course it comprises: its own number, verifiable the same way.
Who teaches this
Common questions
Do I need all four, or can I take just the one I work with?
Each course stands alone and states its own prerequisites, with one pairing: the two wave courses are Part 1 and Part 2 of a single subject, and Part 2 assumes Part 1 throughout. The sequence exists because the terms are added together in practice, and because the errors that matter most are the ones at the boundaries between them.
Is this the same material as the sea-trials course?
No, and the boundary is deliberate. ISO 15016 & Speed Trials teaches the correction chain as a procedure: what a trial must do, in what order, to produce a defensible curve. This sequence teaches the physics of each term at a depth that procedure cannot carry, and it applies equally to continuous monitoring, where there is no trial and no ideal day.
Will this let me build my own correction model?
It will let you understand, implement and audit the published methods, and judge where they stop being trustworthy. Building a new validated method is research, and the courses are honest about where the published ones came from and what they cost to validate.