Lines plans show the hull form of a vessel. A lines plan consists of three views; the plan view (a top-down view of the vessel, with waterlines), the profile view (a side-view of the ship, with buttock lines), and the body plan view (a view of the ends of the vessel, with station lines). As ships are generally symmetrical, the plan view may be split on the centreline and the body plan may show the aft end on one side and the fore end on the other. Where drawing space is limited, it is tradition to place the views centred and overtop of eachother.
Traditionally, the starboard side is shown - the stern to the left and the bow to the right. The practice is reversed in the United States, where the bow runs to the left and the stern to the right. The aft perpendicular and forward perpendicular are marked with vertical lines, with an even 10 divisions between (stations). Locations where the stations cross the profile view are where transverse sections are taken for the body plan.
The baseline is marked, with waterlines taken at regular intervals (such as 1 meter draught). The design waterline if often noted as well. These show as horizontal lines in both the profile and body plan view. Where waterlines intersect the profile (or bodyplan) view, horizontal sections are taken and shown on the plan view.
The centreline is marked, with buttocks taken at regular intervals (such as 1 meter outboard). These show as vertical lines in the bodyplan view, and horizontal lines in plan view. They may be marked with roman numerals. Where buttocks intersect the plan or body plan view, elevations are taken and shown on the profile view.