Ship design involves thousands of details

How do you verify ship motion performance as early in your project as possible?

Components, weight distribution, materials, layout, accommodations, electrical and IT systems, and power systems make ship design one of the most challenging juggling acts to pull off successfully. Fortunately, software has evolved with the practice to help keep the myriad details in check and help move projects forward.

Yet the ship’s performance at sea is a complex function of all the particulars of the design

The customer is waiting with their list of requirements to check off in terms of motion performance at sea, turning capabilities, and more. So how do you verify performance and increase the chances of a design that meets and beats those requirements?

Tank testing is the most accurate, but it’s a slow and expensive prospect. A detailed CFD study is more cost-effective than tank testing, but can still be far too time-consuming to complete many different variations in the ship design. But CFD is not the only software technique available in ship motion analysis.

What’s needed is cost-effective ship motion analysis software tools that are flexible enough in the early stages of ship design

At this stage, the hull is conceptualized but not necessarily all the fine details. Software like this must quickly resolve ship motion across a range of sea states and maneuvers. This seakeeping and maneuvering software is even better if you can make design changes and compare.

ShipMo3D is ship seakeeping and maneuvering software. It can be used at any stage of a vessel’s operational life, from the early stages of design to confirming a loadout for a specific operation. With standard vessel information like hull lines, inertia, hull appendage, and propeller performance, designers and analysts can calculate ship motion in a range of sea states in a straightforward and consistent process. 

Introducing ShipMo3D

ShipMo3D is ship seakeeping and maneuvering software. This tool gives a clear picture of ship motion performance based on all fundamental ship parameters. ShipMo3D helps you evaluate ship motion using a consistent and standardized process.

How can ShipMo3D help you?

Rapidly evaluate seakeeping ship motion response. Ship design projects have a million details that all interact with each other. It can take time to unwind how all these factors affect ship performance. Use ShipMo3D’s frequency-domain seakeeping analysis to rapidly calculate specific ship design performance across a broad range of sea conditions and forward speeds. This rapid feedback helps you quickly cut through the confusion and incrementally improve the ship design.

Calculate acceleration at any location on the vessel. Acceleration is the primary factor in establishing the effects on crew and equipment. But ship motion can result in complex changes in acceleration through the entire hull. Spot-check detailed statistics on accelerations anywhere on the ship as it moves in a seaway using ShipMo3D’s virtual probes called Seakeeping Positions.

Verify ship motion maneuvering response. Ship maneuvers, like the zig-zag test, require varying commands based on the ship condition over time. ShipMo3D’s time domain maneuvering tools allow ship designers to explore and verify the control of ships. Explore maneuver control capabilities of the rudder, propulsion, and turning performance.

Assess maneuvering in a seaway. Ship response is complex while maneuvering through a seaway. A time domain capability that integrates a seaway with maneuvering is needed to understand a complete picture of ship motion. Explore the combined seakeeping and maneuvering capabilities, including nonlinear buoyancy and wave excitation, to see the changes in ship maneuvering response in severe sea states.

Forget limiting hull form factors. Accuracy of strip theory tools break down with squat or awkward-shaped hulls. ShipMo3D is based on 3D potential code to address any midline-symmetric mono or multi-hull vessel.

Use hydrodynamic calculations that account for forward speed. Hydrodynamic parameters like diffraction and radiation can be sensitive to the forward speed of a hull in the water. Without accounting for the effects of forward speed, errors and uncertainty start to grow in the forces and motions. ShipMo3D uses hydrodynamic effects, including diffraction and radiation, that account for the effects of forward speed of the hull.

Compute performance of active stabilizer fins. Active stabilizer can have a large impact on controlling ship motion, but only when sized correctly. Evaluate performance yourself using different foil sizes. Rapidly check the effect of ship motion with and without active stabilizer fins to illustrate the potential for improved performance at sea and during maneuvers.

Easily apply commonly used hull appendages. Hull appendages are small but can have a big impact on ship motion response. Use ShipMo3D’s ship model construction interface to easily define commonly used hull appendages, like bilge keels, skegs, and more.

Validated at full scale.

Ship motion software needs concrete validation to be trusted. In 1998, the Canadian Navy measured sea state and full-scale ship motion of the HMCS Nipigon in a wide range of speeds and directions. The data from this is used to validate new versions of ShipMo3D on an ongoing basis.

Dig into the details of ship motion analysis:

  • Resolve hydrodynamic response of symmetric hulls of any aspect ratio or shape
  • Automatically resolve wet and dry numerical hull mesh from displacement and trim
  • Verify the fully assembled virtual ship hull with appendage models using built-in 3D viewer
  • Capture the effects of forward ship speed on wave excitation and radiation
  • Capture the effect of changing wetted hull area in extreme seas with time domain nonlinear buoyancy and wave excitation
  • Easily calculate and view ship motion RAO in different combinations of forward speed, wave heading, and frequency
  • Maintain heading with active rudder control
  • Control specific course with combined active rudder sway and heading control
  • Schedule maneuver commands at stage points in time
  • Automate reporting of common performance metrics like Motion-Induced Interruption and Sea Sickness Index

“We find the numerous roll reduction models of particular use for the evaluation of anti-roll devices”

At Robert Allan Ltd. ShipMo3D is a valued tool for the prediction of ship motions and seakeeping performance. It is quick and easy to set up an analysis for preliminary predictions; while subsequent customization allows complexity to be added as the design of the vessel progresses, increasing the accuracy of the seakeeping predictions. We find the numerous roll reduction models of particular use for the evaluation of anti-roll devices.

The thorough ShipMo3D documentation and the many papers published by Dr. Kevin McTaggart provide transparency in the calculations and numerical methods, and the validation studies instil confidence in the results.

The integration of ShipMo3D with ProteusDS further opens up possibilities for even more complex seakeeping analysis without the need to replicate fundamental work, streamlining the analysis process. We have no hesitation in recommending ShipMo3D.

 

Scott Newbury, Naval Architect and Hydrodynamicist
Robert Allan Ltd, BC, Canada

“We found that we were able to quickly analyze ship maneuverability. This allowed us to confirm that the ship would pass requirements put forth by ABS and IMO…”

If ShipMo3D only provided maneuvering calculations, it would be harder to justify the price. The program has a lot more features which we have not begun to look at in depth but think will help our engineering team on future projects.

We found that we were able to quickly analyze ship maneuverability. This allowed us to confirm that the ship would pass requirements put forth by ABS and IMO, as well as to get turn rating such as rate of turning ability as defined in ABS’ Guide for Vessel Maneuverability.

Being able to model Azimuthing propulsors as well as Traditional rudders when analyzing Maneuverability in FreeMo was a huge advantage. This allowed us to compare characteristics between a traditional rudder design and that of an azimuthing propulsor design.

Working with DSA Ocean staff to support ShipMo3D has been a real pleasure. They respond to all questions and concerns in a timely manner and they take the time to walk the user through any problems that might arise.  Additionally, the online tutorials are a huge help and provide the knowledge needed to get working in the program.

I would recommend ShipMo3D as it provides a user friendly interface with a relatively easy learning curve.

Chanse M. Riess, Naval Architect
TAI Engineers, LA, USA

“The validation from the documentation of the software seemed strong, but the vessels used in the validation differ from the ships we typically work with.”

The main concern we had was regarding the accuracy of the results, particularly looking at full and model scale validation. ShipMo3D is slightly intricate to get working as intended but after a good amount of time and experimenting, I was able to get the hang of it and help provide data in different forms of analysis needed for different projects.

The validation from the documentation of the software seemed strong, but the vessels used in the validation differ from the ships we typically work with. Our own validation for both seakeeping and maneuvering from known model and full scale tests from our end was mixed, but the software was able to give some level of confidence mainly on the seakeeping end. The maneuvering capabilities seems mainly suitable for shaft line propulsion and I would still be interested in more validation of the software, especially with podded propulsion.

My favorite feature is the capacity to directly import model meshes into the software that eased the process of new runs and rapid development alongside our hull form development. The large sets of appendages provide great benefits for more complex hulls. The large options of outputs and visualizations also help considerably in double checking runs, too.

One of the other greatest benefits would be the excellent customer service and support that is quick to reply. I have spent many days back and forth with ShipMo3D, with quick and patient help from those at DSA Ocean to help me get well acquainted with it.

While I am interested in more validation of the software and continual improvements for new features and refinements, I would recommend it for the core seakeeping capabilities of the software in its capabilities of using Green’s theorem.

Aaron Tam, Naval Architect
Finland

“...we are a defense contractor in the US. We have significant cyber security requirements that took some time to work through to use commercial software…”

We had a seakeeping software in house that we were happy with for strip theory solutions. The majority of our contracts only required strip theory validation for seakeeping. But recently, some study and concept design contracts were coming through that required a panel code software for seakeeping analysis. We had one panel code software program that was available to us, but it was too cumbersome to use, also only operating in the time domain, led to long and complex analysis. ShipMo3D offered a panel theory code which operated in the frequency and time domain. It was the best of both worlds!

But an obstacle we faced was the fact that we are a defense contractor in the US. We have significant cyber security requirements that took some time to work through to use commercial software like ShipMo3D, but we were able to get there in the end.

We found ShipMo3D had an easy to use interface that worked well for standard preliminary design seakeeping analysis. It was only slightly more complex than a strip theory tool, but at a higher level of accuracy. I would recommend ShipMo3D as it is great value with highly customizable inputs and a good customer support team.

Robert Lanoue, Senior Engineer
General Dynamics NASSCO, CA, USA

ShipMo3D Overview

ShipMo3D is the best place to start ship motion analysis

Download ShipMo3D using the button below. After installation, you need a license key to activate the software product to use it. Contact DSA Ocean staff at support@dsaocean.com if you need a commercial key to activate your software.

ShipMo3D Features

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Team

Generate hull form from station-keyed hull lines
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Add common hull appendages like bilge keels, skegs, and foils
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Combined time domain seakeeping and maneuvering capability
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Nonlinear option for wave excitation and buoyancy in maneuvering response
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Antiroll U-tube and slosh tank capabilities
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Active stabilizer capability
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Heading, course, and forward speed control in maneuvering simulation
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Rapid calculation of RAO
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Rapid calculation of irregular sea state response
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Download and install on a single computer
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Download and install on multiple computers for registered Regular Users
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No limit to concurrent use of software
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