SHIBU Flashcards
Naval Architecture
Types of Ship Resistance
- Frictional Resistance: water/hull interface
- Presssure (Form) Resistance: bow/stern, where water is pushed aside
- Wave resistance Cw: waves created by pressure differentials at bow, shoulders, stern (hence, bulbous bow to cancel out)
- Added Wave Resistance (pitching, rolling, heaving)
- Air Resistance
Hull Shape: influence on
- cargo space
- Seaworthiness (stability, movements, manoevrability, vibrations/forces)
- Speed (resistance ~ v^2)
Lll, Lwl
Load Line Length:
used for freeboard calculations, regulations, class certificate, etc
Lwl: distance between points where bow/stern are going through Summer draft mark , less shell plating (i.e. moulded!)
Moulded
dimensions outside frames but inside shell (without shell plating)
Ship dimensions, general
sheer: extra buoyance forward/aft
Camber & co
- Camber: drainage of deck
- rise of floor: lead water inside to centreline for pumping out
Plimsoll Mark
Carene & co
Carene V [m^3] = moulded underwater volume according to lines plan so without shell plating
Water Displacement [m^3] = V * c (coefficient for shell plating, rudder, prop, appendices) ~ 1.01
Displacement [t] = V * c * rho
Displacement
Displacement = Deadweight (DWT) + Lightship (LWT)
LWT: empty ship, no cargo, fuel, crew
DWT: everything a ship can carry
CCC (cargo carrying capacity) : everything the ship is designed to carry is part of the variable DWT
Ship heights
- Air draught: vertical distance from waterline to highest point of ship
- Depth: base line to upper, continuous deck
- Draught: maximal depth underwater, incl shell plating
- Freeboard: waterline to Freeboard Deck Line above Plimsoll Mark
GT ./. NT
Gross Tonnage: dimensionless, calculated based on (moulded) volume below maindeck and enclosed spaces above maindeck
Nett Tonnage: GT reduced by crew spaces, nav equipment, partly propulsion, ballast, etc (not less than 30% of GT)
Block Coefficient
CB
Other form coefficients
Waterplane coefficient: Cw
Midship Section coefficient: Cm
Lines plan
- Waterlines : horizontal slices
- Ordinates/Stations: cross sections
- Verticals/Buttocks: longitudinal slices => sheer plan
- Diagonals = Sent Lines
Lines Plan (example)
Greater spacing in water lines, buttocks, ordinates => finer lines = smaller coefficients
Drawings : general
A number of plans have to be submitted for approval by Flag and Class
Construction drawings to be approved by class
Safety generally to be approved by Flag
Drawings: Class required
- GA Plan
- Lines Plan
- Construction Plans Profile/Deck
- Transverse Sections, incl Midship Section
- Double Bottom Construction
- Fore-/Aft Ship
- Engine Foundation
- Deckhouse
….
Drawings: Flag required
- GA Plan
- Capacity Plan
- Safety Equipment
- Stability Calculations
- all Class approved drawings
GA Plan
Division and arrangement of the ship :
Views:
- Stb side view
- Plan view (horizontals) of most important decks
- Cross sections (like Ordinates/Stations)
division into compartments; location of bulkheads; location/arrangement of superstructure; major equipment
Data:
- principal dimensions
- volume of holds
- tonnage
- deadweight
- engine power; speed
- Class
Drawing: Midship Section
Transverse section
Principal dimensions, quality, and thickness of: shell plating; deck plating; longitudinal stiffening; transverse frames; web frames
maximum longitudinal bending moment
Equipment Numbers (anchors and chains)
Principal vessel dimensions, engine power, speed, Classification
Drawings: Shell Expansion
Showing every single shell plate and openings (eg for repairs)
Seems -
Butts |
Bulkheads
Minimum 3 watertight bulkheads:
1. Forepeak bh (= collision bh)
2. Engine Room bh
3. Aftpeak bh
Strakes
Forces on vessel
Forces from the outside:
* Static waterpressure
* Waves hitting the hull
* Wind
* Movement of ship
Forces on the ship from inside:
* Cargo
* Ballast water
* Hull construction itself
* Accommodation & Bridge
* Equipment (engineroom, cranes, etc.
Sheering forces
SWBM
Still Water Bending Moment
extreme fibres <=> neutral axis
WBM
Wave Bending Moment
extreme fibers <=> neutral axis
Local Stresses
-
Panting stresses, pitching (changing water pressure), hull frames and plating (bow and
sometimes stern) - Pounding stresses, extreme pitching (slamming), bottom plating bow
- Diagonal: Racking, due to rolling or unequal loading: transversal stiffeners required
Vibration stresses, by engine and propeller, good propeller design (no cavitation) and
heavy foundation in engine room - Dry docking stresses, vertical local upwards forces
- Vertical stresses, by deck loads and masts
Transverse Framing System
- for smaller ships < 70m
- frames transversal
- Girders for longitudinal stiffening
solid floor = full floor
Longitudinal Framing System
- longer ships > 120 m
- frames longitudinal
- Bulkheads and floors for transverse stiffening
solid floor = full floor
where members go through watertight floors: horseshoe plates
Shipareas
Double Bottom:
purpose
- Increase strength
- For ballast tanks in low point of ship, low KG
- List and trim control
- Tanks for fuel, water, oil, etc.
- Additional safety for load and ship in case of damage by collision or
running aground - Flat cargo deck / square box hold
Double Bottom:
constrution drawing
Double Bottom:
parts in picture
- Full Floor
2 Side girder
6 Airholes
8 Tanktop
19 Bottom Shell
20 Heating coils
21 Ballast Tank pipe
Double Bottom
construction longitudinal
Lightening and Manholes in girders and floor: to reduce weight and for
accessibility / inspection.
Bracket Floor, Solid Floor & Solid Floor Watertight for transverse strength
Buckling vs Bending
Double Bottom
construction longitudinal (2/2)
Ship bottom
longitudinal
Longitudinal:
* Every transverse frame length a bracket floor
* Every third or fourth transverse frame length a solid floor
* Fore ship, pounding area: Every second transverse frame length a solid floor
* Engine room: Every transverse frame length a solid floor
* Watertight floors are thicker because of a corrosion addition, if frames go through: horseshoe plates to make it watertight again
Double bottom:
transverse framing
- For shorter ships, the SWBM and WBM are less, so for longitudinal
stiffening the girders are sufficient. - Every frame spacing the frames are constructed as floors.
- In Engine room and pounding area’s: all solid floors
- Elswhere: in between solid floors 2 or 3 bracket floors:
Double Bottom
Construction traverse
Double bottom construction transverse
* Centre girder
* Side girder
* Bottom strake
* Tanktop
* Bottom frame
* Inner bottom frame
McGregor hatches
1. Coaming
2. wheels
3. hatch panel
4. horse
5. pull wire
Pontoon hatchcovers
- pontoon hatch cover
- hatch cradle
- beam
- hatch coaming
- top rail
- hold
- tanktop
- wedges
Hydraulic hatches
- (hatch) hinges
- hatch
- main hinge
- hydraulic cylinder
- wheel
- ramp
bulkheads:
goal
- Strength and stiffness
- Watertight divisions
- Segregated spaces for cargo, ballast, fuel, etc.
- Slowing down or preventing fire
3 transverse bulkheads minimum
Watertight subdivision
3 transversal bulkheads: requirements
Collision bulkhead
* Extra requirements for strength and location
* No openings, manholes or doors allowed in collision bulkhead
* Position between 5 and 8% of total length of ship from FPP
=> Too far forward?
> danger of damage in case of collision
=> Too far aft?
> working deck will be flooded when fore peak fully flooded
Engine room bulkheads (fore and aft)
* Fore: for watertightness and fire protection towards cargo / passengers
* Engine room aft bulkhead and aft peak bulkhead mostly the same.
* Stern tube is constructed in watertight aft peak tank. Water in aft peak tank can be used as cooling for propeller shaft.
Watertight vs Weathertight
- Watertight as defined in SOLAS is: capable of preventing the passage of water in any direction under the head of water likely to occur in intact and damaged conditions.
- Weathertight is defined as that in any sea conditions water will not penetrate the ship.
Watertight doors: swing or sliding
More than 5 closing devices (Vorreiber); activation must be possible from bridge
Anchor equipment
Anchor windlass
5 Electro-motor
4 Gearbox
3 Band brake
7 Anchor chain
13 Chain stopper
Anchor
Parts
- crown/shackle
- shank
- flukes
- crown pin
- crown plate
- anchor chain w swivel
anchor chain
each lenghth = shackle: 27.5 m
- anchor shank
- anchor link
- swivel
- open link
- enlarged link
- kenter shackle
- crown shackle
Rope buildup
protection agains shaving & UV
1 fibre
2 thread
3 yarn
4 strand
5 3 strand rope
Turnbuckle
- Gaff
- House
- Thread
- Eye
Shackles
- bow with safety pin
- bow with screw-bold
- D-shackle with safety bolt and nut
- D-shackle with screw bolt
Pounding - Panting
3 main strakes
cargo gear:
advantatges ./. disadvantages
+
faster
everywhere/anytime available => flexibility
control condition / quality
greater t/c earning potential
familiarity w system
layout specific for this vsls cargo carrying characteristics
-
extra weight
extra space
extra Class inspections / certifications
crew occupied / certification
extra mainenance
stability
visibility
upfront CAPEX and OPEX
Why to anchor
SHIBU
- safety / emergency
- manoevring
- waiting
- cargo operations
Different anchor types
(SHIBU)
no need to know the anchor pics/names
conventional: SPEK, Hall, Pool
HHP anchors: high holding power
SHHP SUPER HHP (for yachts only)
where to find equipment number
Class certificate
Midship Section
Why ballasting
Stability
Trim
Decrease bending moment
Increase manoeuvrability
Heeling angle during on/of loading
water piping diagram
diamond w interrupted line: strainer
non-return vv: from white to black
seacocks
Steering System components
- steering wheel/autopilot
- transfer system: bridge -> steering engine
- steering engine
- rudder stock
- rudder blade
3 most important bulkheads
forepeak (5-8% from Fpp), aftpeak, engine room
can have doors/penetrations but not in collision bulhead
duct keel
space in between 2 centre girders
transversal frames
Floors
If manholes in floors: solid floor
If no openings: watertight floor
+ bracket floors
Mixed framing
FWD (pounding; panting) / AFT (weight; vibrations => needs stiffness for e.g. prop alignment): transversal
Midships: longitudinal
Bracket floor
If not full across; but just pieces (individual plates)
Webframe
above double bottom
À big plate (almost like a huge bulkhead; but open in middle)
tansversal framing:
why?
cheaper, lighter, easier to build
when bending moments are lesser (shorter vsls; fore-/aftship)
sternframe
at stern (12)
other name for centregirder, which continues after prop
11: rudder horn
hatches: goals
access holds
close holds weathertight
strength of the vessel
space for deck cargo
watertight doors ./. weathertight
differences
5+ latchings (Vorreiber)
sliding/hinged
withstand water column, if entire adjacent compartment flooded
weathertight: only for above water
Forces on Ship
SHIBU
static ./. dynamic
Forces from the outside:
* Static waterpressure
* Waves hitting the hull
* Wind
* Movement of ship
Forces on the ship from inside:
* Cargo
* Ballast water
* Hull construction itself
* Accommodation & Bridge
* Equipment (engineroom, cranes, etc.)
* vibration
Bending moment
def
SHIBU
The result of vertical forces acting on a ship as a result of local differences between weight and buoyancy. The total of these forces should be zero, otherwise
change of draft will occur. At sea, the bending moment will change as a result of wave impact which than periodically changes the buoyancy distribution.
Note: The maximum allowed bending moment of a vessel is restricted by the class society to certain limits, which are different under port and sea conditions.
Flagstate
SHIBU
National authorities (ILT) by choice of Flagstate
- safety of people on board and interaction with environment
- Often on basis of IMO conventions
- Certificates like Tonnage Certificate
- And often but not always the rest is delegated to classification societies
- Surveyors
types of floors
SHIBU
solid floors
wateright floors
bracket floors
Double bottom construction longitudinal
-
Keel strake + centre girder/centre keel + top plating = backbone of the
ship see page 162 for all strakes - Centre girder (vertical keel) is watertight and can be double constructed: page 172 nr 6 Duct keel, can be used as a cofferdam or pipe tunnel
- Keel strake, from bow to stern is part of the hull plating / bottom strake, very important for longitudinal strength, always thicker or doubled
- Side girders, as long as possible, 1 or 2 on each side, sometimes
watertight
holes in e.g. full/solid floors
SHIBU
- lightening holes
- manholes
./.
- air holes
- drain holes
3 different floors
SHIBU
watertight floors
solid = full floors
bracket floors
Longitudian framing
floor layout
SHIBU
- Every transverse frame length a bracket floor
- Every third or fourth transverse frame length a solid floor
- Fore ship, pounding area: every second transverse frame length a solid floor
- Engine room: Every transverse frame length a solid floor
- Watertight floors are thicker because of a corrosion addition, if frames go through: horseshoe plates to make it watertight again
Transversal framing
floor layout
- Every frame spacing the frames are constructed as floors.
- In Engine room and pounding area’s: all solid floors
- Elswhere: in between solid floors 2 or 3 bracket floors
Holland Profile
type of stiffening profile: a rolled steel section with a distinctive asymmetrical shape, designed to provide structural strength while reducing weight.
Key Features of the Holland Profile:
* Asymmetrical Shape: Unlike traditional flat bars or angles, the Holland Profile has a wider flange on one side and a narrower web, improving load distribution and efficiency.
* Efficient Strength-to-Weight Ratio: The design optimizes structural strength while minimizing the amount of steel used.
Steel vs Iron
difference: composition and properties
Composition
* Iron (Fe): A pure metal extracted from iron ore.
* Steel: An alloy of iron and carbon, sometimes with other elements like chromium, nickel, or manganese for enhanced properties.
Strength and Hardness
* Iron: softer and more malleable in its pure form (wrought iron), but brittle in its impure form (cast iron).
* Steel: stronger and harder due to the carbon content, which improves durability and resistance to deformation.
Corrosion Resistance
* Iron: rusts easily when exposed to moisture and oxygen.
* Steel: more resistant to rust, especially stainless steel, which contains chromium to prevent oxidation.
Equipment number:
relevance
SHIBU
- anchor weight (smaller for HHP than conventional)
- size of chain studlinks
- length of anchor chain
- towing lines
- number, lengths and MBL of mooring lines
why ballast
SHIBU
- trim
- stability
- decrease bending moment
- increase manoevrability
- compensate healing during loading/unloading
Rudder types
SHIBU
Spade
Flap
Mariner
shipbuilding material:
considerations
SHIBU
- Usability / practicality
- Costs
- Strength
- Toughness
- Hardness
- repairability (worldwide!)
- sustainability en recycling ability
different shipbuilding materials
SHIBU
- Wood
- Concrete
- Iron
- Steel
- Aluminum
- Synthetic: Polyester / Epoxy / polyethylene with reinforcing fibers as glass, carbon, aramid (Kevlar, Twaron), composite with foam, wood, etc.
steel: weakening
SHIBU
- corrosion
- erosion (caviation)
- fatigue mechanical wear&tear (vibration; bending; etc)
corrosion:
types
SHIBU
- electrochemical (slow/non aggressive; prevent through coating, epoxy, paint)
- galvanic (less noble eaten up: Magnesium, Zinc, Aluminium, Steel, Copper, Nickel, … Gold)
prop/hull corrosion
SHIBU
bronze prop would eat up steel hull
=> sacrificial anodes:
Magnesium (FreshW)
Aluminium (brackish)
Zinc (SeaW)
paint coat buildup
SHIBU
Primer
Paint system
Antifouling
- Tough layer releasing the biocide
- Soft layer with binding agent which slowly dissolves
- Self Polishing where outer layer continuously shreds.
Dry Docking preparation
SHIBU
- Tanks and holds clean and free of gasses
- Certificate gas proof when welding or cutting is required
- Ship cleaned according to Marpol
- Cranes or derricks parked
- Deck closed
- Toilets cleaned and locked
- Dock list with duties prepared
- Appropriate trim / ballast
- Switch off depth gauge
- paint/consumables/spares ordered and delivered
Dry Docking: procedure
SHIBU
- Dock master is supervisor (time in logbook)
- Centre the ship with lines in dock
- Engine stopped – dock based winches used to position the ship
- Dry dock is pumped empty
- Draft marks to know water level above keel blocks
- When ship touches keel blocks: on the blocks (time in logbook)
- Stability of ship decreases when half afloat / half on blocks / deballasting
- Stability of dry dock! Large Free surface area
- Clean outside of hull immediately, dirt and fouling easier to remove when still wet
Dry Dock
surveys
SHIBU
- Propeller, tail shaft, stern tube
- Rudderstock, rudder
- Underwaterhull
- anchor, anchor chain, chain locker
- Water inlet / outlet; overboard valves
- Sea chest, cooling system
- sacrificial anodes
- sterntube
why practically all ships build in steel
fire resistance
dry dock layout
keel blocks; side blocks; side sponso; crane rail
floating; graving; slip; lift
bulkhead fire protection
A (best) - C
C: only non-combustible
B: preventing 30 min flame & smoke passage standard fire test
A: preventing 1 hour flame & smoke passage standard fire test
-30; -60 …
minutes within which temperature rise on non-exposed side must not exceed +140 deg bzw max 180 deg
how to calculate equipment number
arguments:
displacement; windage area
find where: SOLAS
main components of any steering gear
SHIBU
- Steering wheel / automatic pilot
- Transfer system brigde – steering engine
- Steering engine
- Rudder stock
- Rudderblade
Steering gear: requiremnets
SHIBU
Rudder has to be strong enough to withstand:
* Shifting from maximum angle PS to SB or back within time frame
* Maximum rudder angle running ahead and aft
* Helm to SB, ship to SB
* Helm straight ahead: rudder straight ahead
* Helm place where helmsman has non obstructed view over fore part ship
* Emergency steering gear
* Rudder angle indicator
transverse framed stern
(example pic)
SHIBU
1: frames
2: ice strengthening frames
3: web frames
4: (transversal) deck beams
5: (longitudinal) deck girders
6: duct kee
longitudinal framing w double bottom
(example pic)
SHIBU
1: shell plating
2: longitudinal bulkhead
3: transverse bulkhead
4: longitudinal bulkhead
5: lower hopper
6: tanktop
7: d//b tank
8: side longitudinals
9: bottom longitudinals
10: upper longitudinals
11: bulkhead stiffener
13: cross tie
16: water tight floor
17: bracket floor
18: side girder
static forces
(also; examples)
- water on deck
- ice accretion
- cargo on deck
structural members of various panels
