Initially start by creating a list of your bulky items, then look to get their dimensional details...
Again, we’ve tried to simplify this process for you by creating a pdf download detailing the most common equipment dimensions. Click the following hyperlink to download our canal boat equipment dimensional data sheet
Armed with these dimensions begin a jigsaw like task of arranging and rearranging the items until you begin to get some interesting layouts, pay special attention to those that make good use of the available space.
Keep this process basic just use outlines of the equipment as no doubt you'll run through many different configurations. Either use pencil so you can erase and rework the design or prefferably trace over previous designs, this way you can look over old designs and compare concepts side by side.
What we’ve found is one piece of the jigsaw often leads to another. For example the location of a bed can determine the position of a bulkhead wall which then creates a corridor or a doorway which then starts to create the foundation for the adjacent room.