It's not easy to design a high performance boat. Engineers need tools for composite structural design, and to manage and mitigate injurious shock and vibration. Maine Marine Composites has developed one of the few simulator programs available for high-speed planing craft.
MMC's POWERSEA program has been used in a number of new-design projects, including the SOCOM Combatant Craft Medium Mk 1 project. MMC recently entered into a contract with the Office of Naval Research (ONR) to enhance and extend the program to improve its accuracy and range.
POWERSEA predicts the motion of a planing boat in calm water, regular or irregular seas. You specify the forward velocity or thrust and the shape of the waves or wave spectrum – POWERSEA calculates the hull’s motion including surge, heave and pitch displacements, velocities and accelerations.
POWERSEA can be controlled via OLE Automation and can be extended using external DLL models to satisfy virtually any design simulation requirement.
You can specify the surge velocity or the thrust – POWERSEA predicts the corresponding thrust or velocity for you. Thrust can be specified in terms of steady or ramped force, power or velocity. In all cases POWERSEA will predict three vertical degrees of freedom: surge, heave and pitch.
POWERSEA can tell you whether the ride will be comfortable and safe. Acceleration time-data generated by POWERSEA can be used to predict the probability of damage to materials stowed on deck due to extreme accelerations. You can use the POWERSEA acceleration spectra to predict the incidence of seasickness in a given set of sea conditions.
The dynamic stability of a planing craft is a serious concern to the designer. It is much more cost effective to use a computer to predict porpoising behavior in advance than to build the boat and find out that it porpoises afterwards. POWERSEA can predict the rang of loading and operating conditions that will lead to porpoising.
When you design a high-speed planing boat, one of your concerns is the dynamic stability of the vessel. Each planing hull will respond strongly to certain frequencies of encounter – you need to know that your hull-form does not have a strong negative response to waves that you are likely to encounter.
You can use the Response Analysis capability of POWERSEA to run repeated analyses at different wavelength-to-boat length ratios, finding the surge, heave, pitch and power response to each frequency. A Response Analysis is especially useful when you want to make sure that your high-speed craft does not exhibit extreme responses to waves in a given lake or river, or to commonly-encountered wakes in a particular shipping channel.
To increase your confidence in the results of a POWERSEA analysis, POWERSEA can perform Savitsky planing and pre-planing analyses. These analyses use the same geometry data that you use for time-domain simulation, so you know you are comparing "apples to apples."