Paid SpecialistCertificate

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.

Lessons
6
Quiz questions
51
Exercises
1 (10 min)
Calculators
1
Time
About 60 min
Price
€149+ VAT
Certificate
Graded final exam, then a PDF certificate with a number anyone can verify
Who it's for
Performance analysts, naval architects, weather-routing users and anyone whose work depends on knowing what the seaway costs: this part builds the physical understanding; Part 2 builds the working method.
Assumed knowledge
Our course Ship Resistance Fundamentals: the calm-water floor every added term is measured against. Comfort with a squared quantity and a ratio is all the mathematics needed.
Taught by

Christos Papandreou

CEO & Founder, Blue Autonomy

  • Naval architect and marine engineer, National Technical University of Athens
  • 15 years of experience in fleet performance and operational data
  • Chief Scientific Officer, NEMO, previously DeepSea Technologies, StormGeo, Athenian Sea Carriers, PwC

Part of the Added Weather Resistance specialisation.

What you will be able to do

By the end of the course. Each outcome names the lessons that deliver it, and the final exam samples every one of them.

  1. Define added resistance in waves, place its magnitude against the calm-water floor, and name the four places in performance work where the number is decisive. Lesson 1
  2. Distinguish the reflection (diffraction) and motion-induced mechanisms of added resistance, and predict which dominates for a given ship, sea and heading. Lesson 2
  3. Read a hull's added-resistance response curve (reflection plateau, motion resonance, long-wave decay) and place a given sea on it from the wavelength-to-ship-length ratio, heading and speed. Lesson 3
  4. Explain what a wave spectrum says, relate significant wave height to wave energy, and avoid the classic error of feeding Hs-derived amplitudes into regular-wave formulas. Lesson 4
  5. Name the three sources of wave data and their honest characters, read what a wave model actually serves per grid point, and feed the right period (peak, zero-crossing, first-moment mean or energy) to the right method. Lesson 5
  6. Compare towing tanks, CFD and semi-empirical formulas as prediction routes, and explain what a transfer function is and why arbitrary headings were the field's long-standing gap. Lesson 6

Of all the numbers in vessel performance, added resistance in waves is the one experts argue about most, and the one everything else quietly depends on. Sea-trial curves are corrected by it. Weather routing optimises against it. Performance monitoring filters around it. Voyage claims stand or fall on it. It is genuinely hard: a complicated physical response, driven by an input, the sea state, that is itself only ever estimated.

The subject is big enough that this academy teaches it in two parts, and this is the first: the physics and the sea. What the added resistance is and why it rules so much of practice. The two distinct mechanisms, wave reflection at the hull and motion-induced radiation, and why they dominate in different seas and on different headings. How a single hull answers each individual wavelength, which is the response curve every later method is secretly a model of. What a wave spectrum actually says, why significant wave height alone underdetermines the problem, and the honest confusion of wave periods, four different "periods" circulate for the same sea, and feeding the wrong one into a calculation is one of the field's quietest large errors. Where wave data comes from at all: hindcast models, buoys and human eyes, and what each can and cannot know. And finally the three families of method, tanks, CFD and semi-empirical formulas, and how the industry composes them.

Part 2 takes over from there: the SNNM method itself, the spectral machinery that turns a response curve and a sea state into one number, and the discipline of trusting and spending that number.

The opening lesson is free to read as a sample.

What the course covers

  1. The Second Resistance: What Waves Add and Why It Rules So Much 9 min
  2. Two Mechanisms: Reflection at the Bow, Motion of the Ship 8 min
  3. The Response Curve: How One Hull Answers Each Wave 8 min
  4. Describing the Sea: Regular Waves, Spectra, and the Hs Trap 18 min + exercise
  5. Where Wave Data Comes From: Models, Buoys, and the Period Zoo 9 min
  6. The Methods Landscape: Tanks, CFD, and Formulas 8 min

€149 + VAT

€184.76 including 24% VAT, which is what an individual in the EU pays. Outside the EU no VAT is added. A company in another EU country pays the net price once its VAT number is confirmed in VIES, the EU's register; a company in Greece pays the 24%. Checkout shows the total before you pay.

Paid once, for one person, for as long as the Academy runs: every lesson, the Excel workbook, the final examination and the certificate. Part of the Added Weather Resistance specialisation, which costs less than its courses bought one at a time.

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All prices · Refunds: 7 days, unless you have started

Common questions

What exactly is included?

6 lessons (about 60 minutes in total), 51 quiz questions with explained answers, and 1 working Excel calculator: Wave energy and regime reader.

How much does it cost?

€149 plus VAT, paid once: €184.76 with 24% VAT, which is what an individual in the EU pays; outside the EU no VAT is added, and a company in another EU country with a VAT number valid in VIES pays the net price. That buys every lesson, the Excel workbook, the final examination and the certificate, for one person, for as long as the Academy runs. The course is also part of the Added Weather Resistance specialisation, which costs less than its courses bought one at a time. Everything else is on the pricing page.

Is there work to do, or is it only reading?

1 lesson carries a required exercise, about 10 minutes of hands-on work in total. You download that lesson's Excel workbook, follow the numbered steps against the numbers the lesson states, then change one input and watch the answer move. The exercises are where the method stops being something you have read and becomes something you can run; the stated course time includes them.

Do I get a certificate?

Yes. The course ends with a graded final exam, marked on our server rather than in your browser: you see your score and which questions you got wrong, but not the answers, because the questions are drawn from a pool. Pass it and you get a PDF certificate in your name, with a certificate number on it.

That number is the point. Anyone you show the certificate to can check it themselves at academy.blueautonomy.gr/verify, with no account and no email to us: the page states the name, the course and the date we issued it. A certificate nobody can verify is a decorated PDF, and we would rather issue one that stands up.

Can I preview the course?

Yes: the first lesson, The Second Resistance: What Waves Add and Why It Rules So Much, is free to read in full. It is a real lesson, not a trailer: same depth, same quiz.

Do I need prior knowledge?

Our course Ship Resistance Fundamentals: the calm-water floor every added term is measured against. Comfort with a squared quantity and a ratio is all the mathematics needed.