USCG Healy in Arctic Sea Ice

Surviving the Arctic: Polar Class Icebreakers

The Polar regions of our planet are not pleasant. They demand uncompromising strength, vast reserves of energy, and flexibility to adapt with each challenge. To meet these demands, Polar class icebreakers go beyond anything we expect for a normal ship. How do they voyage into vast desolate regions and return home safe?

Icebreaker Mackinaw in Sea Ice

Ramming the Ice: Icebreaker Propulsion

A giant engine, set in the hull of a tank. That is an icebreaker. With massive electric motors. With cutting edge propeller that allow the ship to spin on a dime. Looking at icebreakers, propulsion is more than just a massive power plant. It’s smart power.

Freighter in Ice

Breaking the Ice: Icebreakers

Ice breakers drive into the ice pack and crack the ice, right? Ships this size involve a little more complexity. The trick isn’t breaking the ice. The trick is intentionally colliding your vessel . . . and surviving.

Electric Yacht Charging

Electric Yacht Charging

Electric power entices us with its flexibility and adaptability. And that extends to our charging sources. We gain the ability to recharge our batteries from nearly any source, assuming everything works together. Discover the critical issues to combine multiple charging sources for electric propulsion.

Comparison of Different Lithium Battery Chemistries

Batteries for Electric Propulsion

Which battery to choose? The batteries form one of the most expensive components in electric propulsion. Today, review the basic battery chemistries out there, allowing you to quickly identify the best battery strategy.

Electric Yacht System Design Title

Electric Yacht System Design

Going electric requires you to design a whole custom electric system for your ship. The challenge with electric systems is the interaction. The requirements for one minor component may determine key settings for the whole system. Today I cover some key settings for the electric system. After deciding these points, the complexity of shopping should simplify into a few simple paths.

Emergency Electric Propulsion

Designing an electric system requires more than just spinning a propeller. Much of an electric boat focuses around safety and emergency planning. This article covers several key decisions to design an electric system that delivers far more than propulsion. Instead, our electric system ensures reliable safety.

Title - 5 Myths with Electric Yachts

5 Myths with Electric Propulsion

Electric power and electric propulsion are still growing industries for yachts and small ships. In this field, a few marketers may stretch the truth a little to make sale. This led to many myths and misunderstand about electric propulsion. Today I debunk five common myths.

How to Design a Ship

How to design a ship? How to go from a blank sheet of paper to a sensible design for a ship, when you have nothing to start with? So here are my secrets revealed.

Lying with Numbers

A critical review of my previous analysis with an eye towards statistics and the importance of context in numbers.

The Value of Life

The Value of Life

Why would you pay more for engineering than for the ship? The value of engineering comes from the lives protected, not the design of the yacht. How much is that protection worth? This risk analysis has an answer to the value of safety.

Commercial Ship Safety

Commercial ships are a world apart from recreational yachts. They contend with tougher requirements, and they need far more safety features. But what are those differences? How is the commercial ship safer?

How Propulsion Works: Classifying Ship Propulsion

No doubt, the math of propulsion devices is complicated. But it is all the same physics. By dividing each of these devices into their essential tasks, we find new opportunities. New methods of propulsion from different combinations of old tricks. Insight into this continuum allows us to better classify marine propulsion and dissect past successes to search for new combinations.

Ever Given Maneuvering Options

Ever Given: Maneuvering Options

How to maneuver a massive freighter into port? CAREFULLY. We design freighters around the scenario of open ocean passage at full speed. But each freighter needs to enter port, pass through canals, and a host of other precision maneuvers executed at a fraction of their design speed. How do massive commercial ships manage precision maneuvers every day?

Ever Given: What We Don’t Know

Like everyone else, I watched the story of the Ever Given and formed my own theories about what happened. Except I was wrong. As the events unfolded, new information came out and I learned the increasing complexity of the accident. Each time, I developed a new theory, which failed with new information. Over a year later, what is the answer? Let’s review what we know and still do not know about the Ever Given incident.

Stability Letters Explained

For small vessels, the major problem with stability letters is explaining it to the captains. Today I will review a stability letter and give plain English interpretation of all the boring mumbo-jumbo.

Three Neat Tricks with Marine Cranes

Three neat things you didn’t know about marine cranes! Every now and then, it’s fun to step back and appreciate the innovation that allowed us to adapt industrial cranes to the marine environment.

Extendable knuckle boom crane

Cranes on Ships: Introduction to Crane Integration

In the marine world, we see cranes daily; they are very useful pieces of equipment. Despite their common appearance, we need to remember their potential for disaster. Cranes on ships generate new, subtle risks for lifting operations. Unless you know what to look for, the risks can go undetected. This article reviews the major dangers of cranes on ships.


Strength and Stiffness: Design of Structural Foundations

No foundation is perfect. Each design reveals new insight and opportunities for further improvement. The art of foundation design finds an efficient arrangement to redistribute concentrated loads into the general ship structure. I review basic strategies for foundation design.

Example of Inspector

Class Societies

Class societies are not perfect, but they are absolutely necessary. We need organizations to provide quality assurance on ships, whose primary motivation lies solely in the quality of the ship, and not with national interests. Despite this necessity, a class society works best when we remember that they are not perfect. Everyone has their bias, and when we balance these biases, we create a fine seaworthy ship.

Kit boat construction supplies

5 Steps to (NOT) Build a Boat

No matter what, building your own yacht will always require more than you anticipated. Before making the commitment to build your own boat, take time to seriously consider all the hidden costs and extra effort required. The best yacht for you is the one you can finish.

shipwreck. Capsized ship.

Free Surface Moment

Without proper management, the shifting liquid in a ship’s tanks can create a lethal scenario. Free surface moment (FSM) is one of the most frequently misunderstood elements in ship operation. The deck officer that values their life wants to understand free surface moment. The physics behind it, and how it applies to ship operating limits.

Composite Materials

Theoretically, composites promise strength several thousand times greater than steel. So why don’t we have composite materials everywhere? The practical design of composites severly limits their capabilities. Once you understand the practical limits, it provides a useful design guide for how to apply composites and maximize their advantages.

Practical Stability Test: Naval Architect’s Guide

Every naval architect learns the theory of how to perform a stability test. But a well executed stability test employs very little theory, and a great deal of practical experience. This guide imparts some of that hard earned experience to make your next stability test go well.

Stability Test Theory

What science could possibly link moving a few weights on deck with calculating the light ship weight? Armed with knowledge, we carefully exploit physics to achieve high quality science without the fancy equipment. Today I explain some of the theory behind the stability test.

Extendable knuckle boom crane

Practical Stability Test: Chief Engineer’s Guide

A stability test requires extensive work to prepare the vessel. Where do you go to find that work list? This guide should give you some advanced warning of what to expect. It covers all the practical matters for a Chief Engineer to prepare for their next stability test.

shipwreck. Capsized ship.

Practical Stability Test: Master’s Guide

Smooth stability tests require planning, and practicality. As the vessel Master, you want to prepare for this thing that completely disrupts vessel operations. But you are a busy person, and engineers are very long winded. Instead, this guide provides a brief overview, focusing on the major elements that concern you with a stability test.

Extendable knuckle boom crane

Practical Stability Test: Owner’s Guide

What are the practical steps necessary to execute a stability test? How to avoid the pitfalls? Who do you call to arrange everything? This guide gives advice to the vessel owner on how to prepare for a stability test, from start to finish. Instead of theory, we focus on the logistics and coordination.

When Need Stability Test - Title Slide

When You Need a Stability Test

Certain as the sea, ships will require stability tests at some point in their life. Or maybe not. This article discusses the different types of stability tests and when regulations require them.

Stability Test Title Pic

What is a Stability Test

Stability tests do not arrive instantly after you order one. It takes time and planning, and you should expect extensive coordination with several different organizations. But the ultimate benefit justifies the expense: a ship with reliable stability performance. This article unravels some of the mystery behind a stability test and why you want one.

Weight Control

Weight Control

Weight control is not sexy, but the consequences of ignoring it can be very scary. If we ignore weight control, we risk a potentially unusable ship. That is why proper weight control starts with the right attitude: understanding the risks and the necessity of a weight estimate.

UNREP: Systems Integration

Underway Replenishment

Naval architects work daily as systems integrators, but it’s difficult to point to any one system and show where this adds value. So today I want to review some T-AO UNREP equipment, and show how none of this is possible without systems integration.

Which Engineer

Which Engineer

Ships evolved to require a combination of expertise from highly specialized disciplines. If you want a modern vessel, expect a modern team of experts. So let’s meet all the different roles and learn who it takes to create a modern ship.

Ship Model Scaling

The physics of model scaling make it impossible to perfectly convert between model scale and ship scale. Learn how to get around the scaling correlation problem and convert from model scale to ship scale measurements.

Next Level Hydrodynamics

Next Level Hydrodynamics

Time for an upgrade! Far beyond the single purpose testing facility, the modern towing tank expanded into a Swiss Army knife of experiments. Armed with new gadgets and advanced capabilities. Time to see what new tricks the tank holds for us!

The Ship Towing Tank

It may look like a swimming pool, but towing tanks exist for a different purpose. Dragging models down the tank propelled the science of ship design forward across the years. These pools deliver critical measurements for ship hydrodynamics. Discover why we pay such a high price for a fundamental tool of ship design.

Guts of CFD: Multiphase Modeling

In computational fluid dynamics (CFD), we often need to model scenarios that involve more than one fluid. Volume of fluid modeling (VOF) expands the capabilities of CFD to allow limitless combinations of different fluids. The world of VOF encompasses everything from droplets of diesel spraying in cylinder all the way up to tsunami waves crashing against the city of Tokyo. How does VOF achieve this, and what are the implications for CFD modeling?

Practical CFD Modeling: Mesh Deformation

Mesh deformation is incredibly frustrating, complicated, unstable . . . and unavoidable if you want to incorporate body motions into CFD. Modeling body motion demands mesh deformation, changing the mesh on the fly, while using it to solve transport equations. As you might expect, that brings a host of new challenges. This reviews several new strategies that the CFD engineers needs to consider.

Practical CFD Modeling: Time Variation

When we add the time domain, simulations change from modeling steady scenarios to unsteady, where boundary conditions change over time. Beyond the physics, modeling unsteady flow requires a few changes to the CFD solver. Inner iterations, timestep, Courant Number, and data management all enter into the strategy for the CFD engineer. Today we discuss each of these.

Practical CFD Modeling: Volume of Fluid Modeling

Computational Fluid Dynamics (CFD) can model multiple fluids with the volume of fluid method. (VOF) The volume of fluid method opens new horizons for advanced modeling, which requires additional planning from the CFD engineer. Dive into the boundary conditions, meshing strategy, stability concerns, and more. Discover the world of VOF modeling.

Practical CFD Modeling: Turbulence

Turbulence demands modeling just like any other equation in computational fluid dynamics (CFD). As the CFD engineer, you need to describe boundary conditions for your turbulence equations. This article describes how to define boundary conditions for turbulence and provides typical values for normal simulations.

How to Cut the Bunker Bill

Ready or not, here it comes! No matter who you talk to, IMO 2020 promises to be a time of uncertain fuel prices. If fuel prices will go up, your fuel consumption needs to go down. Here are eight practical ways to reduce your fuel consumption.

Guts of CFD: Near Wall Effects

Turbulence does tricky things near walls. Boundary layers and laminar sublayers compact interesting flow patterns into a very small space. Small it may be, but experience proved we cannot ignore it. The boundary layer forms on the body, which is our object of interest, arguably the most critical region. Turbulence is most critical near the wall, and we need to consider near wall effects.

Guts of CFD: Turbulence

How we address turbulence is the defining feature of modern computational fluid dynamics (CFD). No modern computer has the power to directly compute the full details of turbulence (as of 2019). Instead, we make approximations and develop empirical models. What type of approximation, and which models should you select?

Guts of CFD: CFD Linear Solution

The heart of any CFD program is an extremely efficient linear algebra solver. But CFD equations are non-linear. How do we stretch the limits of linear algebra to accommodate non-linear CFD equations? How do we take the mathematics from one cell and apply them to millions of cells?

How to Design a Waterjet: Key Elements of Waterjets

What makes a waterjet work? What is the difference between a good and bad waterjet? Waterjets may appear to be brutes of power, but they rely on delicately balanced design equations. Learn the common elements that go into all waterjets and discover the best practices that you should expect from any decent waterjet design.

Practical CFD Modeling: Judging Convergence

CFD convergence is not an exact science. The CFD engineer relies on three tools to judge when a simulation finishes: monitors, flow patterns, and residuals. But none of these tools work 100% of the time. The well-trained engineer understands how to use these tools and how to combine them into a cohesive picture and reliably judge a converged CFD simulation.

Guts of CFD: Interpolation Equations

The core of all calculus problems require us to consider something infinitely small. Ask a computer to ponder the concept of infinity and watch its circuits fry. If we want to solve the equations of computational fluid dynamics (CFD), we need a way to fake calculus. This impacts the stability, the mesh quality, and the ultimate simulation quality. Enter interpolation equations.

Guts of CFD: Transport Equation

What is the utility of a transport equation? What do they achieve? Transport equations form the fundamental language of computational fluid dynamics (CFD). CFD engineers use them to communicate ideas, program CFD software, and diagnose problems with their simulations. But they only work if you understand the language. Today we explain transport equations and the significance of their terms.

Guts of CFD: Navier Stokes Equations

Navier Stokes Equation. Shrouded in mystery and intimidation. Navier Stokes is essential to CFD, and to all fluid mechanics. This equation defines the basic properties of fluid motion. But there is more to gain from understanding the meaning of the equation rather than memorizing its derivation. Today we review Navier Stokes Equation with a focus on the meaning behind the math.

Practical CFD: General Approach

Just fresh out of college, and the boss assigned your first project for computational fluid dynamics (CFD). You are excited. You can’t wait to begin the challenge. You sit down at your computer, start up the CFD software . . . and freeze like a deer in headlights. How to begin? What to do first? Today we discuss the general workflow for a CFD project and highlight some general modeling advice.

CFD Workflow

What happens behind the curtain when the CFD engineer goes to work? What goes into making a CFD simulation? As a project manager, you need to understand the workflow of a CFD project; this helps you plan the project and track budget expenses. When we understand the workflow, we know the right questions and can anticipate project delays.

Which CFD?

Is there anything that CFD can’t do? Practically speaking, we can achieve the result, but you may regret paying for the answer. Several CFD projects involve combinations of different CFD methodologies. Combined together, they evolve into a major project risk. Gain some insight about the risk factors for your next CFD project. Plan a strategy to minimize project risks so that you don’t get caught by combining unknown cost increases.

What is CFD

What is CFD? It uses the computer and adds to our capabilities for fluid mechanics analysis. If used improperly, it can become an incredible waste of time and money. With the right engineer, CFD can be cost effective, incredibly informative, and offer unparalleled flexibility. But what is this wonder of modern science? Learn more about this expansive tool.

Six Ways to Break the Ship

Why are ship structures so labor intensive to design? Engineers need to anticipate multiple methods of failure, which makes a lot of work. The trick of efficient structural analysis focuses on recognizing which methods of failure are likely in each scenario. This article reveals six major methods of structural failure, with examples of common applications. Because it will be the failure mode you didn’t consider that ultimately leads to catastrophe.

Waterjets: When to Use, Pros and Cons

Waterjets: When to Use, Pros and Cons

Waterjets are fun. They give you great maneuvering control and promise much higher efficiency at high speeds. But that flexibility comes with the price of more subtle limits on performance. Used incorrectly, waterjets perform worse than propellers. This article focuses on the merits of waterjets, with focus on the most important factor: efficiency.

Improve Engineering Value: Extract the Most from Engineering Simulations

Improve Engineering Value

We all want to feel good about paying for engineering analysis. Sometimes the best answer drives us to maximize value, rather than minimize cost. In those cases, you do better to go beyond basic safety and search for enhancements. Today we discuss four engineering tasks where you can maximize your value. Extract every last drop of knowledge from your engineering project.

America’s Cup Hydrofoils: Dangers and Solutions

No discussion of hydrofoils is complete without addressing their application to the 2013 America’s Cup yachts. Catamarans screamed across the ocean. But with all that excitement, we sometimes forget how the crew jeopardized their lives in every race. This article presents an engineering perspective on the America’s Cup hydrofoils of 2013, with options for improvement.

Hydrofoil Control: How to Stay on Foil

Why would an airplane company design a ship? When considering hydrofoil ships, aircraft share many of the same requirements. More specifically, every hydrofoil vessel needs a method of motion control, even sailing hydrofoils. This article discusses the problem of hydrofoil control and several solutions.

Meet Intercon Articulated Tug Barge Connector

Meet the Intercon AT/B connector system. A beautiful piece of engineering used to connect tugs and barges for inland and coastal trade.

Stability Fails at Seakeeping

Stability and seakeeping are frequently misunderstood. To understand the limits of these sciences, we must unveil the motivation behind their development. How to guarantee ship safety on an uncertain ocean?

Hydrodynamics and Hull Design

A refined hull shape epitomizes the link between tradition and science. When we link the science of ship design with the experience of past ships, we identify the successes and isolate previous failures. This article glimpses into the background of hydrodynamics by exploring the link between the science of Bernoulli’s equation and the shape of ship hulls.

Graph: Hullform Design Space

Video: Selecting the Right Hullform

Monohull, catamaran, trimaran . . . so many choices. Which hullform to pick? Can we draw upon any science to guide our choices, or we beg Lady Luck to guide us? This article provides a rational and design map for selecting hullforms applicable to any type of mission. This organized approach allows us to see past the limitations of historic examples and consider new alternatives.

Tons in a Pound Advert

How Many Tons in a Pound?

How man tons in a pound? When ships weigh thousands of tons, you really need to know which type of ton. So take five minutes and get clarity on the esoteric measurements of ship design.

Example of FEA Mesh [2]

Six Tip to Improve Your FEA

An experienced engineer doesn’t have some magic button to deliver great FEA. Masters of FEA trade-craft hoard many little tricks and nuggets of wisdom to deliver better FEA. These tricks yield better ways to detect human errors and ensure model reliability. Or methods to deliver faster results. Today we share six nuggets of wisdom for better FEA.

Graph: Hullform Design Space

How do I Select the Right Hull?

Monohull, catamaran, trimaran . . […]

Control Fins on Bow of SWATH

Smooth Sailing: Pros and Cons of a SWATH Vessel

Welcome to luxury cruising.  Glide […]

Fred Olsen

Why You Want a Trimaran: Pros and Cons of a Trimaran

Three hulls are better than […]

Yacht Owners Cabin

Me and My Six Imaginary Friends: The Practicalities of Yacht Layouts

What distinguishes a yacht designer […]

Plate Bending - Medium Resolution Mesh

Six Keys to Better Marine FEA

Tips to Improve Your FEA […]

Example of a Stress Singularity

Trust Your Singularity

Why FEA Singularities Are Acceptable […]

Stress Results – Small Element Size

Mesh Size Does Matter

FEA Errors from Mesh Size […]

Example of an FEA Stress Plot [1]

Reviewing FEA Analysis

Get The Most From Your […]

Miami Bridge Collapse and Professional Engineers

  Many heard about the […]


I confess.  I get excited […]

Example of FEA Results

How to Run FEA

An Overview of FEA Work […]

Example of FEA Mesh [2]

Five Minute FEA

How to Contract an FEA […]

How to Make a Boat Propeller

I love to learn how […]

Blade Sections

Propellers By the Numbers: Propeller Dimensions

How Propeller Dimensions Affect You […]

In-Cad Simulation

FEA: A Beautiful Lie (Until Proven Otherwise)

The widespread availability of FEA […]

Propeller Force Diagram

Propeller Limits: The End of the Line

Efficiency Limitations of Propellers Propellers […]

Speed Demons – Clipper Ships

Today, we pause for a […]

World Fleet by Principal Vessel Tyipe

2017 Shipping Market Review

I love data and science.  […]

FEA Optimization

Skynet is ready to perform […]

Propeller Shoe Fit

Why We Care About The Ship’s Propeller

Propellers are dull, unimaginative, and […]

Single Point Mooring

What Are Single Point Moorings?

Avoid the hassle and frustration […]

Duck with Waves

Why Don’t Boats Look Like Fish?

1.0 The Limitations of Mechanical […]

GHS Tutorials: Macros and Scripting

GHS is nothing without macros. […]

Title Testing List and Loll

Do We Have a Problem: Testing for List and Angle of Loll

EVER WASTE MONEY ON SPECIALISTS!  Here are a few simple-do-it-yourself tests to check for ship list and angle of loll.

Maersk Propeller

Red Hot Bronze: How to Make a Ship’s Propeller

1.0 Introduction How do you […]

Angle of Loll Title Page

Angle of Loll: Hidden Dangers to Stability

PANIC! That should be your reaction if your ship developed a permanent list. Angle of loll shines like a bright red warning sign, indicating serious stability problems. Today we discuss an angle of loll (AOL): what it is, how to find it, and what to do about it.

GHS Tutorials: Structural Analysis

Did you know that GHS can also do structural analysis?  Often, we only require a simple longitudinal strength analysis.  GHS provides all the tools for this.  


Keep An Even Keel: Dealing With Ship List

Why is Ship List Bad? If ignored, it continues grow and place your ship at risk.  Be proactive and stop the list once you first suspect it.  Your crew

Understanding Steering Gear in Ships

How many different ways can […]

The True Cost of Steel

Steel is cheap.  No one cares about reducing the structure weight just to save on some steel costs, right?  WRONG!  And when you see the next bunkering bill, you will care too.

GHS Tutorials: Intact and Damage Stability

How to perform a stability analysis in GHS? These tutorials explain the process.

Wave Power May Allow Skype for Sailors

Imagine a technology that delivers cheap and reliable vessel communications with land.  Bandwidth high enough for every sailor to enjoy daily video conferencing with their loved ones.

Ten Forgotten Uses for A Catamaran

1.0 Introduction Behold the lowly […]

Bulk Carriers and Ballast Water Treatment

I found this wonderful article that gives a great overview of bulk carriers.  A great reference to quickly understand the essential design aspects of a bulk carrier.

Why Catamarans are Awesome

Consider the use of catamarans as massive industrial equipment.

More GHS Tutorials: Reports And Hydrostatics

General Hydrostatics (GHS):  The de facto standard software for hydrostatics and stability in the USA. Watch these tutorials to learn GHS.

CFD of Bulbous Bow

The Limits of Bulbous Bows

Bulbous bows are not miracle devices. They only work under specific circumstances. Understand the limits of bulbous bows.

How Does a Drillship Work?

We all know that a drillship goes out and drills wells, but can you name all the steps required to drill that well?  Here are a series of fun videos that give an overview about how a drillship works.

Do Bulbous Bows Really Work?

This video provides a quick introduction to bulbous bows.

Newcastle Towing Tank

Understanding Ship Model Testing

Your beautiful new ship is […]

Job Hunting Sign

Finding a Job When No One is Hiring

Advice for unconventional places to find a job for naval architects. Useful when the the economy is slow.

Extreme Roll

Extreme Stability

Ship stability is not about operations in normal weather. See a few examples of how stability protects you from extreme emergencies.

Ship Capsize

Stability Decay

Did you know that a perfectly stable vessel can become unstable and useless?  Understand how stability decay affects your vessel life.

Resistance – Displacement Hull

Many ship designs require a resistance and powering study. This provides an overview of the resistance study.

Project Management

An overview of what you get with project management services.

Global FEA

An overview of the services provided for a global FEA analysis.

FEA for Structure Foundations

An overview of the services provided for FEA of structural foundations.

Structural Detail Design – Component from First Principles

An overview of what you get with services for structural design of foundations.

Stability Test

An overview of what to expect from engineering services for a stability test.

Scantling Calculations

An overview of engineering services to provide structural scantling calculations.

Damage Stability Analysis

What to expect from a damage stability analysis.

Trim and Stability Booklet

What to expect from your engineer when ordering a stability book.

Intact Stability Analysis

Intact stability analysis is part of the process to determine your vessel’s operating limits and satisfy regulatory authorities.

Floodable Lengths Analysis

Floodable lengths are one factor that determines the load line.  This is a measure of reserve buoyancy in the vessel.  Other fac

Skippers Guide to Stability Tests

Every vessel and owner must […]

Ship Deflection in Waves

Watch a big strong ship bend like a reed in the wind.

FEA Quality

This video from NAFEMS covers […]

Brilliant Stern Loading Landing Craft

A brilliant example of naval architecture at its finest. The stern landing craft!