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.

Virtual VCG Diagram

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.

Naval Architect's Guide to Stability Test

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

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.

Chief Engineer Guide to Stability Test

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.

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.

Owners Guide to Stability Test

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: Preparing for IMO 2020

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.

Breakthrough Technology for Oil Spill Cleanup

Extreme spill technology (EST) developed a new approach to oil recovery. It works on the ocean, simpler and more reliable. Want to learn more?

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.

Low Cost / High Performance Computing

If you want it done best, do it yourself! DMS developed a custom built high performance computer (HPC) for CFD calculations. But the exciting part: it cost about what you paid for that Dell workstation!

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 . .

Planing Hull Clickbait

Go FAST Boat: Pros and Cons of a Planing Hull

ZOOM!!!  No better way to

Control Fins on Bow of SWATH

Smooth Sailing: Pros and Cons of a SWATH Vessel

Welcome to luxury cruising.  Glide

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

Six Hours of AWESOME SUPERSHIPS!

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

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,

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

1.0 Introduction NEVER WASTE MONEY

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

1.0 Introduction PANIC!  Well, at

GHS Tutorials: Structural Analysis

Did you know that GHS

VideoList_Clickbait

Keep An Even Keel: Dealing With Ship List

1.0 Introduction List is everywhere

Understanding Steering Gear in Ships

How many different ways can

The True Cost of Steel

1.0 Introduction Hull structural designers

GHS Tutorials: Intact and Damage Stability

Will the ship flip over?

Wave Power May Allow Skype for Sailors

Today, I invite you to

Ten Forgotten Uses for A Catamaran

1.0 Introduction Behold the lowly

Bulk Carriers and Ballast Water Treatment

I found this wonderful article

Why Catamarans are Awesome

If you use a catamaran

More GHS Tutorials: Reports And Hydrostatics

General Hydrostatics (GHS):  The de

CFD of Bulbous Bow

The Limits of Bulbous Bows

I hate bulbous bows!  It

How Does a Drillship Work?

When I first began work

Do Bulbous Bows Really Work?

Do Bulbous Bows Really Work?

Updated GHS Tutorials

I recently improved the audio

How to Evaluate Marine Consultant

Six Steps to Evaluate Your Marine Consultant

Hang in there.  You almost

Consider the Size of Your Consulting Firm

Four Things to Consider in Size of Marine Consultant

Bigger is always better!  Biggest

Newcastle Towing Tank

Understanding Ship Model Testing

Your beautiful new ship is

Where to Find Your Marine Consultant

Finding Your Marine Consultant

Marine consultants provide a valuable,

Stream of code

Wave Macros Updated

You may have noticed that

Job Hunting Sign

Finding a Job When No One is Hiring

Introduction I’m sorry.  I’m so

Rocket Launch

Datawave Marine Science is Back!

It started as an experiment

Experts Expect the Unexpected

What to Expect From a Marine Consultant

Even if you find the

Ship Designer

Why You Need A Marine Consultant

You face a conundrum when

Extreme Roll

Extreme Stability

A contractor comes up to

Ship Capsize

Stability Decay

I knew a ship owner

Resistance – Displacement Hull

  A resistance and powering study

Project Management

Project management is all about

Global FEA

A global finite element analysis

FEA for Structure Foundations

Foundations for large structures are

Stability Test

The purpose of a stability

Scantling Calculations

 Ship structural scantlings are a

Damage Stability Analysis

Damage stability analysis is required to

Trim and Stability Booklet

The trim and stability booklet

Intact Stability Analysis

Intact stability analysis is required

Floodable Lengths Analysis

A floodable lengths analysis happens

OpenProp

We all love open source

OpenSEA Philosophy

1-Nov-2014 In long term projects

oFreq: Hydrodynamic Forces Added

01-Oct-2014:  Hydrodynamic Forces Added It’s

Waves Added

oFreq now has complete sea

Documentation Updated

We now have a rough

Skippers Guide to Stability Tests

Every vessel and owner must

Sorry For the Lack of Response

Hi all, I want to

Ship Deflection in Waves

That big strong ship is

oFreq Core Works!

Mar 13, 2014:  The first

oFreq Debugging Continues

Update.  Debugging of oFreq continues. 

OpenSEA Development Plan

The current plan is to

Interpolation Macros Published

DMS has published a set

Wave Macros Published

DMS has published a set

oFreq Released

oFreq version 0.20 is released. 

Generic Documents

Navy Electrical Engineering Training Series

NEETS – Navy Electrical Engineering

G108 – Commercial Technology in the Yacht Market

The commercial boat industry is

Ankida – A new sail mast concept

Sailing ships were largely dominated

Vortex Hydro Energy – VIVACE

Vortex induced vibrations – Send

Generic Documents

Northlake Shipyard Rates

The following is billing information

FEA Quality

This video from NAFEMS covers

Brilliant Stern Loading Landing Craft

Engineering really shines when we

Welcome to DMS!

Welcome to Datawave Marine Solutions

CONTACT US