Good morning to every member of this forum! This is my first post on this forum and I've just done the registration in order to open this thread. I'm no professional designer, i'm just a guy who recently got interested in yacht world, and in my free time I started figuring my dream yacht and besides not having the technical knowledge to design it perfectly, I'm trying to make it as realistic as possible! Since now I've cleared many doubts by using google or looking to different specs and layout on true finished yacht, but I'm now at a point where an hand from more experienced designers is necessary! To keep this simple, i'm just asking in this post few questions on measures and dimensions: forgive if I make errors or i don't know all the correct terms but english is not my mothertongue and ship parts are not words that are taught commonly Actually my yacht is a LOA 62,5 m (205 foot) displacement yacht with a full beam of 10,8 m. These dimensions seem right to me after i've confronted them with specs of many models on the market. 1) My first questions is about the beam: how is usually intended beam on online brochures and specs? I've found many definitions that say that the beam has to be measured at the waterline: In this case by observing the shape of most of the ships you can be sure that above the waterline the hull gets a bit wider until "main deck floor level" meaning more space for decks, but how much can i expect it to be wider? In another spot on the internet i read that the term "beam" commonly used on websites is referred as the maximum width of the ship at "main deck floor level", and because the hull restricts toward the bottom we'll have less space in the lower deck. And also in this case i would ask: "How much do i reasonoably have to expect?" 2) How much would "tickness" of the hull in the lower deck in this kind of yacht ? i intend the metal plates that separate the inside from the outside like traditional walls, i hope you get what i mean. I've seen in every layout that it varies from stern to bow and not progressively (it's not always increasing or decreasing) 3) How high can be the lower deck? I mean from floor to ceiling since i don't know if the lower deck floor coincides with the waterline or it's above/below it. for now is all i need to know, thank you in advance for your attention!