### Naval Architect Toolbox

The functionality of the previous Naval Architect Pro version is now included in the free evaluation plug-in. The plug-in can be downloaded at Food4Rhino.com or from the link on the left. The evaluation license is valid for 28 days. After 28 days please purchase a license in our Shop.

The Naval Architect Toolbox plug-in for Rhino enables 5 new commands. The commands allow calculation of the hydrostatic properties of relatively complicated hull geometries. This includes hulls with reverse chines, multihulls and classic V- shaped planing hulls which require a section close to the transom for accurate results. Further commands balance a hull in pitch, heel and sink depending on the location of the centre of gravity and displacement. Hydrostatic properties can also be determined at a range of heel angles to display the righting moment curve and other heel angle dependent data. To help with mass analysis, mass properties can be assigned to materials and the total mass and centre of gravity of multiple Rhino objects calculated.

The data can be written to .csv files which can be opened and analysed in Excel. A time and date is automatically added to the file name to keep track of multiple results.

The plug-in is ideal for quickly analysing hull surfaces during the iterative design stage. A symmetric half model is sufficient for hydrostatic analysis and hull balancing. Full models can also be used. All major hydrostatic data is calculated with minimum user input.

The following hydrostatic results will be computed:

- Hull length
- Hull width
- Canoe body draft
- Cb
- Displacement / LWL^3
- CBx
- CBy
- Cbz
- LCB / LWL
- Max section area
- Max section area coefficient
- Waterpane area
- Waterpane coefficient
- Centre of flotation x
- Centre of flotation y
- CF / LWL
- Righting moment
- Waterline length
- Waterline width
- Cp
- Wetted surface area
- Displaced volume

### Description of the tools

#### HullAnalysis

Options and inputs:

- Write results file
- Specify section near transom for analysis of V- hulls
- Draw section area graph
- Use symmetry
- Number of sections
- Hull surface

This command simply calculates various hydrostatic data. Select the options, number of sections and click on the hull surface.

#### HullBalance

Options and inputs:

- Write results file
- Specify section near transom for analysis of V- hulls
- Draw section area graph
- Use symmetry
- Number of sections
- Displaced volume
- Centre of gravity location (point object)
- Hull surface

This command calculates how a hull would float based on the specified mass and centre of gravity. The hull surface will be moved vertically and rotated around the y – axis until the displaced volume matches the input and the longitudinal position of the centre of flotation matches the centre of gravity.

Analysis results will be printed to the screen or written to a file.

#### HullHeel

Options and inputs:

- Number of sections
- Specify section near transom for analysis of V- hulls
- Heel angle increment (degrees)
- Number of increments
- Displaced volume
- Centre of gravity location (point object)
- Hull surface

This command balances the hull at zero degree heel angle and then copies the hull surface and balances it throughout the specified heel angle range. The results are multiple balanced copies of the hull and a file with all results data. The righting moment curve and various other data can be plotted over the heel angle in Excel.

Larger heel angles will require a deck! This command only works with a full model of the hull.

#### SetMatProp

This is a very simple command to populate the material database. Simply click on an object with a material applied either directly or via the object layer. The plug-in will ask for the density, area mass and point mass. The data is saved to the notes box of the material. Existing notes will be kept and moved to the end.

Depending on the units used for the Rhino model and preferences for mass results, different material values have to be specified. For example if the mass is to be calculated in kilograms and the model unit is millimeters the input has to be in kg/mm^{3}, kg/mm^{2} and kg. Inches and pounds will require lb/in^{3}, lb/in^{2} and lb.

#### GetMassProps

Simply select one or more objects. The command will read the material properties, compute the mass and centre of gravity of every selected object and calculate the total. The mass of solid objects will be calculated by multiplying the volume times the density. Surface areas will be multiplied by the area mass and point masses will have the mass of the material assigned. A point will be created at the centre of gravity.