1. Framing Systems Double Bottom Construction Stem & Stern Construction
Ship Construction
Framing Systems
Double Bottom Construction
Stem & Stern Construction

2. Transverse Framing: Many, closely-spaced Frames
Deck Beams tie upper ends of frames
Fewer, deeper & more widely spaced Longitudinals …
Support Inner Bottom & give longitudinal strength
Longitudinals
supporting Decks are called
(Deck) Girders
Additional Decks (supported by
Beams & Girders) increase
Transverse & Longitudinal strength
Transverse Bulkheads provide watertight boundaries, contribute significantly to transverse strength, and provide vertical support for Decks

3. Transverse Framing: Many, closely-spaced Frames Advantages
Open, nearly rectangular interior space
Ideal for stowing large, irregular, break-bulk items, or
Vehicles (Ro-Ro’s)
Disadvantages
Vertical support for decks requires more closely spaced transverse bulkheads (hence smaller compartments) or
Pillars (stanchions) or
Longitudinal bulkheads

4. Longitudinal Framing:
Deep (Web)
Transverse Frames
Few & widely spaced
Smaller, closely-spaced Longitud-nals support shell plating
Side shell longitudinals call stringers
Inner Bottom gives
additional longitudinal &
transverse strength
Girders in high-stress areas:
Double bottom spaces and …
Under main deck

5. Longitudinal Framing:
Deep (Web)
Transverse Frames
Advantages
Widely spaced transverse bulkheads allow for large (i.e., long) continuous cargo spaces (“tanks”)
Ideal for stowing liquids (reduced free surface effects)
Disadvantages
No large, open interior spaces
Difficult to load or unload break-bulk items
Difficult to stow large, irregular shaped items

6. Framing Systems:
Typically, most ships have some combination of transverse & longitudinal framing
L L L L L L L L L L
T T T T T T T T T T T T T T T T T
Bulkhead STIFFENERS
UPPER TWEEN DECK
LOWER TWEEN DECK
Stringer
(LOWER) HOLD
Web Frame
Typical
Transverse
Frames
SECTION VIEW
FLOOR C L
PLAN VIEW C L

7. Double Bottom details:
Rider
Plate
Inner Bottom
(Tank Top)
Air-
hole
Margin
Plate
Frame
Bilge
Bilge
well
Center
Vertical Keel
Limber
hole
Longitudinal
“SOLID” FLOOR
Keel
Plate
Outer
Bottom
Lightening
hole
Reverse Frame
“OPEN” FLOOR
Frame
Longitudinal
Strut

8. Shell Plating details:
(Longitudinal) Rows of plating are called “strakes”
The Keel Plates form the “Keel strake”
The strakes outboard (P&S) of the Keel are the “A” Strakes or “Garboard Strakes”
Strakes are consecutively lettered moving outboard and up the side shell
“G”
Strake
“F” Strake
(Bilge Strake)
“B”
Strake
“C”
Strake
“D”
Strake
“E”
Strake
Keel
Strake
Garboard Strake
(“A” strake)

9. Shell Plating details:
(Longitudinal) Rows of plating are called “strakes”
Welded horizontal joints between strakes are called seams
Welded vertical joints between plates in a given strake are called butts
Strakes that do not run the entire ship length (as the hull surface area decreases at the ends) are drop strakes
“K” Strake Sheer Strake
“J” Strake Through 
“H” Strake drop 
“G” Strake
Bilge (“F”) Strake
Strakes running stem to stern are called through strakes
An oversized plate merging a drop & through strake is a stealer plate
The strake at the deck edge is the sheer strake and is heavier than typical side shell plating

10. Openings in shell plating must:. have rounded corners
Openings in shell plating must: *have rounded corners *be reinforced to make up for missing material
… and on weather deck -- COAMINGS
portholes
Hatch openings below decks
Watertight doors

11. Stem Construction Decks Forward Wrapper Collision Plate Stem Bulkhead
Stringers
Vertical
Stem Post
Rider Plate
Breast
Hooks
Deep
Floors
C.V. Keel
Keel Plate

12. Stern Construction UNBALANCED RUDDER SEMI-BALANCED RUDDER Stern Frame
After
Collision
Bulkhead
Stern
Frame
Steering Gear Room
Deck
Mach’y Rm
Cant
Frames
Rope
Locker
Lug
Rudder
Stock
After
Peak
Tank
Stern
Tube
Pintle
Gudgeon
Rudder
Post
UNBALANCED RUDDER
Propeller
Post
SEMI-BALANCED RUDDER