Engineering Technical Support Services to Support Parametric Ship Hull Modeling in Rhinoceros Software

Page 1 of 10 PERFORMANCE WORK STATEMENT (PWS) FOR ENGINEERING TECHNICAL SUPPORT SERVICES TO SUPPORT PARAMETRIC SHIP HULL MODELING IN RHINO 1.0 GENERAL 1.1 BACKGROUND The Salvage Engineering Response Team (SERT) provides emergent naval architecture support to U.S. Coast Guard (USCG) field units responding to marine casualties. Naval architects at SERT use approved software to build computerized hull models to evaluate ship stability and strength using existing and available ship plans and information. SERT requires contractor assistance to build a parametric hull model creation tool using Rhinoceros software. Rhinoceros is a 3D computer aided design software application developed by McNeel & Associates and approved for use by the USCG. Rhinoceros has a built in Python script editor as well as the graphical algorithm editor “Grasshopper” which have the functionality to create accurate ship models using a rapid hull design and fairing methodology. During marine casualties on commercial ships, information is limited to basic drawings (general arrangements, capacity plan) and principal dimensions (length, breadth, depth, maximum draft, full load displacement). In most cases, some additional information regarding hull form is available including block coefficient and a deadweight scale. Salvage naval architects use this limited information and knowledge of other ship hull forms to generate computerized hull models. Models are tested for accuracy and used to evaluate the ship’s structure and stability during casualty events. A model creation tool capable of parametrically generating models for common types of commercial ships will improve SERT response time and abilities. Using limited information that is available, parametric hull models can be modified in Rhinoceros with minimal user intervention to increase accuracy. 1.2 SCOPE The purpose of this Task Order is to obtain Technical and Engineering Support Services to develop, test, and document a ship hull model creation tool. Software will be limited to Rhinoceros and modules included within the stock distribution of the software (no third-party plug-ins). Commercial ship types, plans, drawings and information for creating ship models will be provided by SERT for development and testing. The modeling tool will not contain protected or proprietary information or drawings. The contractor shall perform the effort required by this TO on a Time and Materials (T&M) basis for all labor. 1.3 OBJECTIVE The objective of this Task Order is to obtain contractor support to develop a Rhinoceros model creation tool that can generate a commercial ship hull model with accurate hydrostatic properties using only limited information available to salvage naval architects during marine casualties. -- 1 of 10 -- Page 2 of 10 1.4 APPLICABLE DOCUMENTS The following reference documents may be helpful to the Contractor in performing the work described in this document: • International Maritime Organization (IMO): MSC.1/Circ/ 1229 of 11 Jan 2007, “Guidelines for the Approval of Stability Instruments.” • U.S. Navy Salvage Engineer’s Handbook, Revision 1 2.0 SPECIFIC REQUIREMENTS/TASKS The Contractor must support the SERT in developing naval architecture tools within Rhino for utilization by the USCG. The development process is divided into three stages/tasks, as described below; specific responsibilities are defined in PWS Sections 2.1 through 2.3.: • Task One – Develop modeling tool for common commercial ship types. • Task Two – Generate ship models with developed modeling tool and validate against actual ship hydrostatic properties. • Task Three – Draft technical paper documenting methodology, use, assumptions, and limitations of the modeling tool 2.1 TASK ONE. Develop modeling tool for common commercial ship types The contractor will use a simplified ship hull modeling methodology to create sample ship hulls and validate their hydrostatic characteristics. The simplified hull modeling technique will be automated within Rhinoceros. 2.1.1 Contractor personnel assigned to this task must complete Hull Design and Fairing Training Level 1 and 2. This course is offered online by Rhino Centre and completion of the course will help the contractor personnel better understand hull design and fairing within Rhinoceros and introduce an existing methodology for parametric creation of hull models using Rhinoceros’ Grasshopper module. 2.1.2 The contractor will develop a written methodology that uses only a commercial ship’s Capacity Plan with a zero trim deadweight scale as input. The methodology will then outline the steps needed to generate a 3D model including iterative solving to attain a model that meets the accuracy of IMO’s “Guidelines for the Approval of Stability Instruments.” 2.1.3 The contractor will implement the rapid modeling methodology in Rhinoceros in a repeatable manner that is mostly automated using Python or Grasshopper. This may only use modules contained within the standard distribution of Rhinoceros software (such as Grasshopper or the built in Python script editor). Third party plug-ins and packages for Rhinoceros should be avoided. 2.2 TASK TWO. Generate and validate ship models The contractor will use the tool and methodology in Task One to generate parametric ship hull models. These models will be created by with limited information (e.g. without a vessel lines drawing). Existing hull models or hydrostatic data for each model created by the rapid modeling tool will be used to validate the results. The contractor will then modify the modeling tool and user interface within Rhinoceros to attain the best accuracy possible using the IMO’s “Guidelines for the Approval of Stability Instruments.” -- 2 of 10 -- Page 3 of 10 2.3 TASK THREE. Draft Technical Paper The contractor must document the creation and tested uses of the model creation tool. A draft technical paper format will be used for documentation. The technical paper should include methodology, te…