Originally Posted by TANSL
Could we know what program/s is/are involved? I would like to try it.
In addition to the weight of the hull, can it calculate the weight of the equipment, of the accommodation, etc. ?
Is it valid also for GRP hulls?
TouchCAD only ( www.touchcad.com
). All described features are standard features in the program.
Normally, I would say that I extract about 85% of the total project weight in this way. The rest can be described as nuts and bolts or other smaller parts that for sure has a weight but would simply be too expensive to specify in a normal design project, not having the budget of say a Formula 1 team.
There are three basic ways to add weights to objects:
1/ As a weight per area unit, where you figure out the weight of for example per square meter. On solid materials, such as for example aluminium, you simply multiply the density of the material 2,7 kilos per liter, by the thickness (1 square meter times a thickness of 1 mm equals one liter of volume). For materials being a combination of materials, such as GRP, sandwich panels, etc., it may be a good idea to measure the actual weight of a sample panel, and extract a weight per square meter weight from that. This method works well for all parts that can be described as real surfaces, for example hull and outer skin, glass panels, sails, tubing and rails, bulkheads and frames, etc.
2/ In some cases, it's more practical to define the weight and location as a given point weight, not being associated with their object area, say a stove, an engine, or a radar unit, which consists of many parts, but where you only have access to the total weight. I then draw a reasonable representation of that unit, being good enough so that you can see what it is, and to make sure that it fits well into the given space. I then specify that the panels are to be ignored by the spreadsheet, and add a simple point at the estimated center of gravity in the 3D model, having the true weight of the object. In this way, I can include almost all major parts of any significant weight, and can move them around if required to adjust the floating balance of the boat. Point weights can be associated to surfaces, curves of points, where the center of gravity is based on the given graphical properties of the respective object.
3/ Curves and polylines (as opposed to surfaces or points) can also be used for weight calculations, for example of rigging. In this case a weight per length unit is applied (unless it's specified as a point weight of course). Also worth noting is that any 2D or 3D lines can be used as measurement lines, showing either segment lengths or accumulated total true 3D length. Quite handy for rigging.