- Speed vs. power vs. boat loading
- Response to waves (seakeeping)
- Possibilities of wave slamming
- ...or do you need to model test as a sales tool to sell your design?
MMC personnel can assist you in constructing accurate models for tank testing or free-running experiments.
- Convert your paper or CAD-based design to a model design using state-of-the-art hull design software
- Recommend a model construction technique (built-up wood, FRP, foam, etc.) for your project
- Build or manage the construction of your model
| || ||Lexan model of deep-Vee offshore fishing boat mounted on dynamometer at Webb Institute.|
Maine Marine Composites has established relationships with most of the hydrodynamics testing facilities (towing tanks) in North America, and can manage your entire testing program
- Create a test matrix appropriate for your budget and design needs
- Recommend the best test facility for your project, taking into account both your budget and your engineering requirements
- Consult during the test program, or manage the entire program
- Analyze the test data and create the final report, including recommendations for design changes if necessary
We will work with you to determine the model loading conditions, operating speeds and wave conditions. Tank testing can be expensive, and proper planning is required.
- Develop a test plan (address issues listed above)
- Select a test facility based on ability to perform your desired tests, geographic proximity, professional reputation, and cost
- Construct an exact scale model of your design including appendages, thrust objects, and anything else that will be wet during the test. We can help you with modeling issues ("Tankery") such as scaling issues and modeling techniques, and we can arrange for the construction of models from wood, plastic, or syntactic foam.
- Consult with the tank staff to select one of the common wave models. You may want to use a simple ideal model such as Pierson-Moskowitz, or you may want to test against an actual spectrum obtained from an NDBC buoy located near your expected operating area.
- Travel to the tank and set up your model. Preparation time for a typical set of tests can extend to a number of days, depending on how complicated your test procedure is.
- Tank personnel will run the tests and collect the data. You should observe this process and participate if you can so that you understand exactly how the tests were performed.
- The tank personnel will post process the data and issue a report. Neglect this step at your peril -- do you really know exactly how they ran the tests and how to scale the results?
- Repack the model and ship it home (or ship it to your client to be placed in a glass showcase).
We can help you with any or all of this -- we've done it many times and we've collected a lot of tankery tricks over the years.
Testing personal watercraft (PWC) on high-speed carriage at NSWC Carderock Division.
| ||Personal Watercraft mounted for high-speed run at NSWC Carderock.|
Free-Running (Radio Controlled) Tests
Some tests have to be run in large basins or even lakes. It is difficult to perform maneuvering tests in a long, slender tank so engineers create radio controlled models and test them in sheltered lakes or basins.
MMC can design and construct radio-controlled models, including everything from the hull-form to the data telemetry system.
Virtual Tank Testing
Tank and model testing can be expensive. An alternative to tank testing is to simulate your design with a computer model, to perform virtual tank testing. Maine Marine Composites has a number of computer analysis tools that can meet some of your analysis needs at a fraction of the cost of a full-blown model testing program.
|Results from radio-controlled MV Hugh Sharp model replicated using ANSYS-AQWA|
The POWERSEA program
Developed by MMC staff, the POWERSEA program predicts the motion of a planing boat in calm water, regular or irregular seas. We specify the forward velocity or thrust and the shape of the waves or wave spectrum, and POWERSEA calculates the hull’s motion including surge, heave and pitch displacements, velocities and accelerations.
POWERSEA is used to predict time dependent effects such as porpoising, deck wetting and boat accelerations:
- Speed/Power analyses of high-speed planing craft in calm water or waves.
- Predicting heave, surge and pitch amplitude, velocity and acceleration at any point on the design.
- Investigating porpoising (vertical oscillations) behavior.
- Estimating dynamic natural frequencies of hull with respect to incident waves.
- Investigating time dependent effects such as porpoising, deck wetting and boat accelerations.
Contact MMC for more information about the POWERSEA program.