This document provides an overview of ship geometry and lines plans. It defines key elements of a lines plan including profiles, body plans, and half breadth plans. It explains that lines plans provide a scaled 2D representation of a ship's complex 3D form through descriptive geometry. Various views, components, and their uses are described, including stations, waterlines, buttocks, and diagonals. The document also outlines common uses of lines plans for calculations related to hydrostatics, stability, capacity, structure, and hydrodynamics.

1. SHIP THEORY
Basics Of ship geometry : Lines Plan
By Jishnu Saji ,
Dept. Of Naval Architecture & Ship Building ,
SNGCE ,
Kerala , India

2. NOTE :
• This ppt covers the basics of ship theory with
lines plan and the very basics of ship geometry
only ,which I had undergone during my first
course of naval architecture recently .
• So ,it is recommended to read textbooks for more
knowledge.
• Some textbooks I would recommend are :
1. Basic Ship Theory Volume 1
2. Principles Of Naval Architecture Vol 1
• Many Of the Pictures in this ppt is taken from
internet , courtesy is extended to the sources.

3. LINES PLAN
• Lines Plan is a 2-d scaled representation of the 3-D complex form of the
ship through descriptive geometry.
• VIEWS:
1.Profile,
2.Body plan
3.Half breadth plan

4. 1. PROFILE
: Projection of the ship on a longitudinal vertical plane
: Stations are vertical lines
: Stations are equally spaced
: Numbering of stations can be 0 to 10 or 0 to 20
: Numbering starts from aft
: Waterlines are horizontal lines
: Waterlines are marked as WL1, WL2 etc.
: Waterlines are equally spaced
: Buttocks are curvilinear
: Buttocks are marked as BTK1, BTKII etc.

5. Actual Projection Of Profile view

6. 2. HALF BREADTH PLAN
: Projection of the ship on a longitudinal horizontal plane
: Drawn below the profile view
: Stations are marked as vertical lines
: Buttocks are drawn parallel to centerline
: Buttocks are straight lines equidistant from the centerline
: Waterlines are curvilinear
: Only half the projection with respect to centerline is drawn
: No. of waterlines in profile and half breadth plan is same
: Diagonals are drawn on the other free half

7. half breadth plan of ship

8. 3. BODY PLAN
: Projection of the ship on a transverse plane
: Drawn on the right side of profile
: Waterlines are horizontal
: Buttocks are vertical lines
: The centerline is marked
: BTK I is closer to centerline
: Stations are curvlinear
: Stations from middle to forward are drawn on the right side
: Stations from aft to middle are drawn on the left side
: Total number of stations in all views is the same
: Diagonals are drawn as inclined lines

9. A computer generated Body Plan

10. Lines Plan

11. USES AND FUNCTIONS OF LINES PLAN
Lines Plan is used for the calculation of the following:
• Hydrostatic calculations
• Capacity calculations
• Trim calculations
• Flooding calculations
• Cross curves of stability calculations
• Fairing and offset reading
• Launching calculations
• Resistance calculations
• Model making
• Calculation of hydrodynamic derivatives
• Calculation o0f hydrodynamic derivatives
• Calculations of bending moment, shearing force etc.
• Shell expansion drawing.

12. OFFSET TABLE
It is a rectilinear tabulation of the following:
• The heights above base line each section where it is
crossed by a buttock line.
• The half breadths at each section where they are
crossed by waterline.
__________________________________________
Use and functions Of Offset Table
• For lofting
• As input to computers for fairing and further
calculations

13. A typical OFFSET TABLE