Specialisation Foundation → Specialist
Propeller & Propulsion
The machine that spends the power, opened up: blade geometry, open-water performance, life behind a hull, and a match to an engine that has to survive twenty-five years of fouling and weather.
- Courses
- 4
- Lessons
- 32
- Time
- About 5 hours
- Price
- €529+ VAT
- Assumed knowledge
- Our course Ship Resistance Fundamentals owns the calm-water resistance the propeller has to overcome, and Naval Architecture for Performance introduces the propeller in three lessons. Neither is compulsory: this sequence builds what it needs where it needs it. School algebra on a scientific calculator (powers, roots and, here and there, a logarithm), a little trigonometry, a square law and a cube law are the whole mathematical requirement.
€529 + VAT for the sequence
The 4 paid courses cost €696 bought one at a time; as a specialisation they are €529, a saving of €167 (24%).
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You own this specialisation. Every course in it is open to you.
Most of the fuel a ship burns at sea ends up as torque on one disc of spinning bronze, and most performance work treats that disc as a single efficiency number. This sequence opens it. It starts with the drawing, because a propeller is a geometry before it is a performance: every open-water coefficient later in the sequence is the consequence of a pitch distribution, a skew line and an area ratio that somebody chose and had reasons for. It then measures that geometry in open water, puts it back behind a hull where the water arrives slowed and uneven, and finally marries it to an engine whose own operating envelope decides whether the match still works when the hull is dirty and the sea is up. The mathematics stays at the level a practitioner computes with, and every method is worked in numbers on one reference ship that runs through all four courses.
What you'll learn
- Read a propeller drawing properly: pitch distribution, rake, skew, the three area ratios, and what each choice was bought with
- Compute KT, KQ and open-water efficiency at a given advance ratio, and find a ship's operating point on an open-water diagram
- Evaluate the Wageningen B-series polynomials as an independent check on a yard's open-water curve, and say where the series stops being trustworthy
- Separate nominal from effective wake, compute hull and relative rotative efficiency, and assemble the chain from effective power to brake power
- Apply the ITTC 1978 method to turn a model result into a ship prediction, and state which coefficients it scales and which it deliberately leaves alone
- Place a specified MCR inside an engine's layout diagram and an operating point inside its load diagram, and explain what sea margin, engine margin and light running margin each protect against
- Diagnose light and heavy running from shipboard data, and estimate what the drift is costing
The sequence
Each course stands alone; this order is the order the knowledge builds.
How the courses build on each other
The order is the order the subject is actually built. Propeller Geometry & Blade Definition comes first because nothing later can be discussed without it: an open-water curve belongs to one blade geometry, a slip figure means nothing until pitch is defined, and a cavitation limit means nothing until blade area is. Open-Water Performance then measures that geometry in the only condition where the propeller can be studied alone, and ends with the systematic series that turn a measurement programme into a design tool. The Propeller Behind the Hull puts the ship back: the wake the propeller really swims in, the thrust the hull takes back, and the ITTC 1978 bookkeeping that lets a tank result predict a ship. Propeller Selection & Engine Matching closes the sequence with the decision the first three courses exist to support: its first half sizes the propeller, and its second half is the only part of the sequence that goes into the engine room. Three boundaries are drawn on purpose. Naval Architecture for Performance introduces the propeller in three lessons; this sequence starts again from the definitions and takes each idea much further, so that course is a useful warm-up rather than a requirement. Shaftline, Stern Tube and Propulsor (available shortly) owns the propeller as machinery: the taper fit, the hub oil, the seals, the watchkeeping. Marine Engineering & Main Engines owns the engine as a commercial object (fuel, emissions, retrofits, and what a derating costs to buy), and its lesson on the operating envelope meets the load diagram and the margins from the engine's side; the fourth course here builds the same diagrams from the propeller's side and works them in numbers. Throughout, the propeller is a hydrodynamic machine, and the engine is the field its operating point has to sit inside.
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Paid Foundation
Propeller Geometry & Blade Definition
What a propeller drawing actually specifies, and how to read one without being caught by its conventions: three views and the quantity each of them owns, pitch in its several incompatible meanings, the blade section as a hydrofoil, rake and skew as two shadows of one line, three different blade areas, and a blade number chosen for a frequency rather than for efficiency.
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Paid Practitioner
Open-Water Performance
What a propeller does on its own, before a hull is put around it: the four coefficients that describe it, the tank test that measures them, the scale correction that makes them usable at full size, and the constructions that turn one chart into a shaft speed, a torque and an independent opinion on somebody else's efficiency claim.
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Paid Practitioner
The Propeller Behind the Hull
What changes when you put a hull in front of a propeller: the wake field it really swims in, the thrust it has to add to overcome its own suction, the efficiencies that reconcile the tank with the ship, and the model test and scaling rules that turn all of it into a power prediction.
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Paid Specialist
Propeller Selection & Engine Matching
The propeller and the engine chosen as one decision: the diameter and revolutions that win or lose most of the efficiency, the blade area and cavitation checks that fence them in, the layout and load diagrams the engine imposes, the three margins that separate a design point from a rating, and how to read a ship's own records once the match starts to age.
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
How is this different from the propeller lessons in Naval Architecture for Performance?
That course gives the propeller three lessons and treats it as one component of a hull's performance story: how thrust is made, what changes behind a hull, how the match to an engine works in outline. This sequence gives the same subject thirty-two lessons and takes every idea to the point where you compute with it on one reference ship. Where that course says open-water efficiency peaks between 0.55 and 0.70, this one has you read the peak off a diagram, see why the ship's own design point sits short of it, as every well-chosen propeller does, size the diameter and revolutions against the limits that set her loading, and defend the blade area you chose.
Will I be able to design a propeller when I finish?
You will be able to size its diameter and revolutions against the limits that bind (draught, aperture and the engines on offer), using thrust loading to see which way to move, check its blade area against Keller's formula, work out the loading and cavitation numbers Burrill's chart is read with, benchmark it against a systematic series, place it against an engine, and audit somebody else's design. Detailed blade design is cavitation-tunnel, lifting-surface and CFD work done by propeller makers and model basins, and the sequence is honest about where the published methods stop and that work begins.
Do I need a towing tank or any special software?
No. Everything is worked with a calculator or a spreadsheet, and the fourth course ships two Excel workbooks: one takes your own ship's propeller design point and three margins to a specified MCR and computes the corner points of the load diagram around it, the other turns a measured power and shaft speed into a light running percentage and the extra fuel at those revolutions.
Do the courses have to be taken in order?
Propeller Geometry & Blade Definition stands alone, and Open-Water Performance asks only for its vocabulary: pitch ratio, blade area ratio, blade number. The Propeller Behind the Hull assumes you can read an open-water diagram, so take it after Open-Water Performance; the fourth course defines again each term it leans on, but reads best after the other three. The order above is the order the subject is built.