1. Nomenclature & Principal Views Lines & Offsets Coefficients of Form
Ship Form
Nomenclature & Principal Views
Lines & Offsets
Coefficients of Form

2. Forward Perpendicular Designed Waterline Plane
Ship Dimensions
Length Overall (LOA)
After Perpendicular
Forward Perpendicular
Designed Waterline Length (DWL)
Length Between Perpendiculars (LBP)
Beam
Designed Waterline Plane
Parallel Midbody
Afterbody (STERN)
Forebody (BOW)
Depth
Midship Section

3. Lines Drawings: waterlines
DWL
WL2
WL1
Baseline
Length Between Perpendiculars (LBP)
Half-Breadth Plan

4. Lines Drawings: sectionsAP FP
Sta
After Sections
Forward Sections
Sta 10 (AP)
Sta 0 (FP)
MIDSHIP SECTION
Sta 2
Sta 8
Sta 6
Sta 4
Body Plan

5. Section Nomenclature Tumblehome Flair Camber Freeboard Depth Beam DWL
Half-breadth
Draft
Deadrise
Baseline

6. Lines Drawings: buttocks
DWL
DWL PLANE
Centerline Plane
BP1
BP2
BP3
Sheer Plan
Butt 1
BP1
Butt 3
Butt 2

7. Sheer & Camber Sheer DWL DWL PLANE Centerline Plane Camber BP1
Sheer Plan
Camber
BP1

8. Lines Drawings Three sets of drawings define the hull shape
Half-Breadth Plan
Body Plan
Sheer Plan
BP1

9. Offsets Ships lines may be represented numerically in a table
For example
Sta No.
30’ (DWL)
25 ‘
20’
… etc.
Baseline
0 (FP) 16 12 10 4 2 35 33 30 6 50 48 45 40
5 (F) 8 42
10(AP) 32 15

10. Offsets
Sta No.
30’ (DWL)
25 ‘
20’
… etc.
Baseline
0 (FP) 16 12 10 4 2 35 33 30 6 50 48 45 40
Half-breadths for different WL’s at a given station may be used to determine the AF of that station
(DWL)30’
25’
20’
15’
10’ 5’
(BL) 0’
B1 = 35
h= 5
A1= ½ (35+33) x 5 = 170
B2 = 33 A2 A3 A4 A5 A6

11. Hull Volume Section Areas define hull shape
Volumes between sections summed to determine displacement volume, 
Midship Section (Station 5)
Area below DWL
Section Volume V5 = ½ (A5+A4) x d

12. Offsets
Likewise, waterplane areas may be calculated from Offset tables
Sta
Sta No.
½ 30’
½ 25’
0 (FP) 16 12 2 35 33 4 50 48
5 (F) 6 8 45 42
10(AP) 40 32
NOTE: The above is distorted because the frame spacing (probably 60’ is not at the same scale as the half-breadths. (Plot to scale below.)

13. Other Hull Form Dimensions
Besides areas & volumes, hull form determines the location of other critical dimensions.
The centroid (geometric center) of the underwater portion of the hull is the Center of Buoyancy B
LCB KB
The vertical location of B is measured from the keel (KB).
The Longitudinal Center of Buoyancy (LCB) is measured from the Forward Perpendicular
The location of B changes with draft (displacement).

14. Other Hull Form Dimensions
Besides areas & volumes, hull form determines the location of other critical dimensions.
The centroid of the waterplane area is the Center of Floatation (F)
Its location (distance from the fwd perpendicular – LCF) is also a function of displacement
LCF F

15. Other Hull Form Dimensions
Besides areas & volumes, hull form determines the location of other critical dimensions.
The distribution of waterplane area determines the Metacentric Radius (BM)
The Center of Buoyancy moves along this arc as the ship rolls
With KB known, the Metacentric Height (KM) becomes an important parameter in stability calculations.
Waterplane Area M B K

16. Hydrostatic Curves
MEAN DRAFT (FT). KM
(FT)
LCF
(AFT FP) (FT)
LCB
MT1
(FT-TON)
TPI
DISPL
in S.W. (L.TONS)
MEAN DRAFT (FT) 27 26 25 24 23 68
1800
268
279
31.1
31.05
31.2
278
277
276
275
274
267
266
1700
1600 67 66
19000
18000
17000
16000
15000 65

17. Hull Volume,  (under DWL)
Coefficients of Form
Block Coefficient: CB =  / (L x B x T) AP
Beam, B
L (along DWL} FP
Hull Volume,  (under DWL)
Block Volume, L x B x T
Draft, T

18. Coefficients of Form Prismatic Coefficient: CP =  / (AF x L)
Hull Volume,  (under DWL)
Prism Volume, (AF x L)
Midship Section Area, AF

19. Coefficients of Form AF Midship Section Coefficient: CM = AF / (B x T)
Beam, B
Note that CM = CB / CP
COF’s are used in the early stages of design to compare characteristics of new design with existing types for estimating performance AF
Draft T
Rectangle, B x T
Same B & T smaller CM