Hydrostats and how they apply


Hi Rhino forum, I am sending a photo with this post. Basically it is a hull drawn. Then created a plane representing a waterline. I split the hull with the waterline, then joined the lower portion of the hull with the split portion of the water plane. This gave me something I could get a volume on. It was converted to gallons and then multiplied by the water weight of a gallon. Answer was 2064 lbs. Assuming this is the weight displayed by the hull? I also did a volume centeroid .
My question is, did I set up this hull proper for a hydrostat analysis? What else can be done to get accurate information from hydrostats? This was a real-time waterline off an existing boat with everything on it(motor,batteries, trolling motor,etc.) no gas though. I was hoping @davidcockey might know something in this area. Thanks,Mark

That sounds correct as long as your model has both sides of the hull. (Its common to only model one side of the hull.) Rather than convert to gallons you can use cubic feet, with 64 lbs per cubic foot for salt water and 62.4 lbs per cubic foot for fresh water.

An alternative method is to use the Hydrostatics command in Rhino. No need to split the hull at the waterline. Just input the waterline height and the volume below the waterline is calculated along with centroids, wetted surface area, etc. Also has an option for using only half of symmetric hull.

Try doing calculations on a simple box and see if you get the expected results.