Displacement
This might not be the standard way to calculate a vessel's displacement. I used this method when calculating specs for a SUP board, and practical experience confirmed it was sufficiently accurate. Calculating displacement is necessary to determine the vessel's draft and locate the waterline. You can then add the freeboard height to get the vessel's total height.
Displacement calculation: two people at 75 kg each, the boat at 50 kg, the motor at 7 kg, the battery at 15 kg, and miscellaneous items at 3 kg. That totals 225 kg. This means the waterline corresponds to a displacement of 225 liters.
I exported the model from Moi3D to SketchUp because the latter can calculate the volume of shapes. While one could use mathematical formulas or even an AI, I chose a different approach. I believe that if you are modeling in a CAD application, this is the most reliable method. In SketchUp, I created a cube larger than the boat. By subtracting the cube from the upper part of the boat, I was left with the lower section, the volume of which I then checked. I found that with the cube positioned at a height of 19 centimeters, the remaining boat section had a volume of 240 liters—a result that satisfied me. If you divide the lower section into two equal volumes (120 and 120 liters), you will find your vessel's center of buoyancy. Knowing this is useful for determining the best placement for passengers.
In DAZ Studio, I created two characters and imported them into SketchUp to verify whether there was enough room in the boat for two passengers—specifically, to see where their knees would be positioned and if there was space to stretch out their legs. I was satisfied with what I saw. I consulted an AI and learned that for my specific conditions—a calm river and a lake with light chop—the minimum freeboard height (the distance from the waterline to the gunwale) should be 20 centimeters, though 25 centimeters is safer. Therefore, the total height of the boat's side should be 19 + 25 = 44 centimeters. I went back to Moi3D and realized I needed to increase the height of the gunwales. Simply scaling the frames vertically wouldn't work, as it would distort the deck and hull lines. Instead, I selected only the deck beams and raised them, thereby establishing the boat's new profile. I added surfaces to the frame structure, cut the cockpit opening into the deck, beveled the transom, and arrived at the result you see here.
