Term
| What are the purpose of cant frames in steel vessels? |
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Definition
| provide strength to shell plating at stern |
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Term
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Definition
| a vertical strength member |
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Term
| what are the synonyms for pillar? |
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Definition
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Term
| why should pillars always be fitted in a vertical line? |
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Definition
| To transmit load directly down to the keel, and not onto beams and deck plates. |
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Term
| why is a pillar fitted under the windlass? |
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Definition
| to absorb the stress, vibration, and weight of the windlass |
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Term
| what is a partial bulkhead |
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Definition
| bulkhead that does not extend across a compartment; used to strengthen the structure |
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Term
| what three things does the size of a pillar depend on? |
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Definition
| load, location, and length |
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Term
| How does acceleration affect the size of the pillar? |
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Definition
| dynamic load can be double the static load |
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Term
| what is the purpose of deck girders? |
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Definition
| support deck beams by reducing span |
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Term
| why should pillars be well protected when cargo is loaded/unloaded? |
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Definition
| to prevent damage, bent pillars provide little to no vertical support |
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Term
| what is the purpose of wood sheathing |
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Definition
insulates - wood has low heat transmission
absorbs damage and protects deck
keeps outer decks cool for passengers
prevents sweating due to rapid temp change under deck
add aesthetic value to appearance of ship |
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Term
| what is the purpose of the stringer plate? |
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Definition
| thicker outboard plating to prevent racking and provide support for cargo hatchess |
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Term
| why should corners of all hulls cut into the strength deck be rounded, doubled, or both? |
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Definition
| to prevent cracks and notches from forming due to stress |
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Term
| differentiate between side stringer, girder, and longitudinal |
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Definition
side stringer: longitudinal strength member inside deck plating
longitudinal: fore and aft strength members in bottom structure
girder: fore and aft longitudinal strength members supporting decks |
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Term
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Definition
provide additional vertical support & act as structural diaphragms to resist racking
create fire & flooding boundaries |
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Term
| what is a 2 compartment ship? |
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Definition
| A ship that can be flooded in 2 compartments and stay afloat |
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Term
| max number of passengers a merchant ship can carry without being considered a passenger vessel? |
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Definition
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Term
| what is the maximum distance the collision bulkhead can be from the stem? |
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Definition
| 1/20th the vessel length at summer load line |
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Term
| what are the functions of the stem? |
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Definition
vertical extension of the keel
gives strength and rigidity to hull along center-line
ties shell plating
gives rigidity to entire bow |
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Term
| advantages of a clipper bow? |
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Definition
additional space and buoyancy
flare throws water away from bow when headed into heavy seas |
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Term
| what is the function of the stern frame? |
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Definition
vertical extension of the keel
provides strength for rudder and single prop
ties shell plating together at stern |
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Term
| pillars give vertical support to... |
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Definition
girders
deck beams
decks
heavy concentrated loads: ground tackle, anchor windlass, line handling winches, capstains |
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Term
| why place pillar under deck beam or girder? |
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Definition
redices deflection by reducing span
relieves stress on beam brackets & transverse frames |
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Term
| top/bottom of pillar (names)? |
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Definition
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Term
| purpose of doubling plate at bottom of pillars? |
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Definition
| to spread the load over larger portion of deck plating |
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Term
| ideal depth of beam brackets |
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Definition
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Term
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Definition
| increases seaworthiness by forming watertight top of hull and contributes strength by acting as upper flange of hull girder |
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Term
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Definition
working platforms for operation of machinery and loading of cargo
living spaces for passengers and crew |
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Term
| Additional purpose of all decks |
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Definition
| serve as horizontal diaphram, keeping the ship in shape longitudinally |
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Term
| Girder stress concentration? |
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Definition
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Term
| 2 methods of insulation on ships? |
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Definition
insulation bats fixed to underside of deck via wire studs
spray on insulation applied directly to steel deck |
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Term
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Definition
insulate space
prevent sweating
noise barrier in engine room decks and bulkheads on passenger vessels |
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Term
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Definition
paint
cement composite that flexes with deck
carpet, tile or linoleum over top of cement composite |
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Term
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Definition
flat plate steel
or
corrugated (adds strength, reduces need for additional framing) |
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Term
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Definition
| acts as auxiliary watertight bow in event actual bow is punctured in collision |
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Term
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Definition
encloses shaft in watertight compartment
required on all screw type vessels
prevents broken prop shaft from flooding aft section of vessel |
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Term
| machinery space bulkheads |
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Definition
enclose machinery spaces - watertight
regulatory requirement due to large through-hulls in engine rooms |
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Term
| 3 bulkheads required by regulation |
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Definition
collision bulkhead
afterpeak bulkhead
machinery space bulkhead |
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Term
| Bulkheads are usually plated... |
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Definition
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Term
| plate thickness thicker towards the bottom of the ship.. |
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Definition
| due to increased water pressure |
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Term
| Why are longitudinal bulkheads avoided |
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Definition
danger of capsizing due to collision and flooding of one side of the ship
but they are seen in tankers |
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Term
| longitudinal bulkheads in tankers |
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Definition
single hull: port and starboard longitudinal bulkheads form boundaries between port, center, and stbd tanks
double hull: usually only centerline longitudinal bulkhead |
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Term
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Definition
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Term
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Definition
straight up and down
classic passenger ship, aided with riveted construction |
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Term
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Definition
| flared bow, extra space and buoyancy, throws water when headed into seas |
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Term
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Definition
| ice breaker, allows bow to ride up on ice and break it with the weight of the vessel |
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Term
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Definition
curved connection between stem and keel
sometimes cast |
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Term
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Definition
| lower stem section joining forefoot to upper stem |
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Term
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Definition
| plate heated and rolled to form plating around upper stem |
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Term
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Definition
| triangular plate that joins plating and reinforces the solid stem bar |
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Term
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Definition
located forward of collision bulkhead
serves as forwardmost ballast tank
exerts greatest moment for trim changes, good for lessening sag |
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Term
| components of forepeak tank |
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Definition
valves and piping
reach rods to open and close valves
swash bulkheads reduce wave motion, can be longitudinally or transverse (generally longitudinal) |
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Term
| Bulbous bow - what vessel speed? |
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Definition
higher vessel speed - improves vessel flow through water, overcomes wave making resistance
acts to fill in trough of bow wave = less power needed to reach medium/high speed |
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Term
| two primary types of sterns |
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Definition
cruiser: rounded, requires cant frames and beams to make curve. older construction
transom: flat, modern construction cuz its cheaper, and waterline is carried further aft |
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