Shiphandler’s Guide - Rowe Flashcards
The disproportionate size ratio of windlass to DWT of ships today can de found in primarily
Ships of what size?
A. 100,000 DWT or greater
B. 50,000 DWT or greater
C. 40,000 DwT or greater
D. NONE OF THE ABOVE
B. 50,000 DWT or greater
Pg 49
What is a single greatest influence upon the magnitude of the title force?
A. Draft
B. Depth ot water
C. UkC
D. Trim
C. UkC
This is due to the blocking effect of a vessel as UK see reduces .
Pg 81
What is the conversion trom KW to Shaft horse power (SHP)?
Shaft HP to tones force?
.74 =1 SHP
100 SHP = 1 T
Pg 89
If their is a choice when entering a bend in a river which part of the turn would be prudent to take:
A. The inside of the bend
B. The outside of the bend
C. Middle Channel.
D, It mates no ditterence
B. The outside of the bend. The flow of the current is the strongest
Pg 77
To slow down a persistently high-speed with a following current, you will put the engines of stern. What will this do to the pivot point and control over the situation?
A pivot point moves after and are at the whim of transverse thrust
B. Pivot point remains forward and have complete control.
C. Pivot point moves after you have Control.
A pivot point moves after and are at the whim of transverse thrust
Pg 72
What technique can be used to keep speed low, controll heading with kicks ahead virtually drive to a desired position and remain there.
SHG- Rowe
Dredging two anchors
Pg 53
What speed Should the vessel be going when approaching the swing area and instant of letting go
the anchor? (turning short round)
A. Minimum for steerageway and SOG as low as possible as stern before applying brake on windless.
B. slow had engines and a stern
C. 2 knot speed through the water and one knot speed through the water.
A. Minimum for steerageway and SOG as low as possible engine astern before applying brake on windless.
Pg 74
Which direction should the bow be canted when turning short round?
A. Towards the deepest swatter in the channel.
B. So that the tide is on the correct quarter to the turn.
C. To starboard.
D. None of the above.
B. So that the tide is on the correct quarter to the turn.
Pg 74
What is the e downside to a diesel - powered Ship with a fixed propeller when utilising the kick ahead method?
The number of starts of the engine
Page 20
True or false the difference between the modern conventional bulbous bow, and the more traditional rounded bow has no significant influence on title flow
True, This should be taken into account in the interest of accuracy
page 81
When twin screws are design too close together the ability to torque or turn is quite poor. What is the best option for maneuvering?
A. Or stop one and use as a single screw.
B. Use them together as one like a single screw.
C. None of the above.
B. Use them together as one like a single screw.
Page 121 SHG – Rowe
How much does the location of the pivot point change when twin screw vessels are used?
A. Pivot point while backing is 1/4 length stern
B. Pivot point making headway 1/8 L to 1/3 L from forward
C. The fundamental concepts remain the same for pivot point.
D. All of the above.
All of the above. An exception would be immensely powerful ships that can turn on the spot.
Page 125 sHG – Rowe
What inherent design feature has limited the efficiency of the traditional tug?
A. The traditional propulsion unit.
B. The position of the towing hook.
C. The high superstructure.
D. A and B only.
D. A and B only.
Traditional propulsion unit and position of towing hook.
Page 129 SHG – row
When the tow line is slacked and the tug is making way, where is the pivot point?
A. Where the tow line contacts the tug.
B. 1/8 L from the bow.
C. 1/4 L from the bow
C. 1/4 L from the bow
Pg 131
True or false unless there are excessive, Highwinds or maximum current should be able to negotiate any turn in a river or channel without tug assistance
False the ships size, shallow, water, tides, or any combination would require tug assistance
Page 150 to 153
True or false the shrouded colors are only found fixed for colors
False shaded colors can be found on CP or fix propellers
Page 110
True or false when installed on larger, single screw shifts the nozzles are usually rid rigidly attached to the ship’s stern.
True in other cases, the shroud moves as one unit with the propeller becoming a nozzle or azimuth drive.
Page 110
Propellers in shrouds tend to have how much transverse thrust?
Very little. flow of water is concentrated on both sides of the whole equally
Page 26
When is Rudder force optimum for vessel?
When the ship is dead in the water and Ford movement is initiated with hard rudder
Page 27
The turning lever for a ship, making sternway is ________ than that of a ship making slight headway.
Smaller. This situation is not helped by the center of when moving aft as the wind comes to the quarter.
Page 41
Trim by the stern with sternway will have which effect on a ship?
A. Intensify wind effect.
B. Nullify wind effect.
C. None of the above.
A. Intensify wind effect. With a pivot point and waypoint further away, you create a larger turning lever.
Pg - 41
What forces may be used on the turning lever of a ship?
Rutter force transverse force, bowthrust force, tug force, and forces of the wind and tide.
Page 12 and 13
What two factors determine how much power should be applied for a kick ahead?
The size of the ship and the needs of the ship handler at the time.
Pg 18
What design may cause a reduction of transverse thrust to the extent that the bow may fall off in either direction?
Hull design
PG – 26
These three factors are the same to create the same turning circle?
RPM, Rudder force, and lateral resistance
Pg 27 - 30
When tidal force is exerted 19 tons of pressure on a 50,000 DWT tanker at anchor with a 3.0 draft ratio what is the force when the draft ratio is 1.1?
64 tons. Longitudinal title force increases by three times
Page 8164
when the tide goes out and a ship is left with a 1.1 draft to depth ratio, the __________ forces of the current have the greatest effect on a ship at anchor.
Lateral forces
Page 83
The force on the beam of a 280,000 DWT ship with a 1.05 depth to draft ratio is 328 tons at .5 kn what is it at 1.5 kn?
700 tons
PG 83
The force of the tide is directly proportional to the _________ of the tidal force?
Square
PG 83
From a dead stop to turning with the ships propulsion in conjunction with the Bow thruster where does the pivot point move when the ship picks up speed?
Moves half ships length from forward. 1/2 L
Page 94
What is a Combinator in reference to CPP systems?
A. Gives the ability to the helmsman to change pitch or engine speed.
B. Built in control that balances a reduction of revolutions at slow speeds.
C. Built in control that balances an increase in revolutions at high speeds.
D. B and C are correct.
B. Built in control that balances a reduction of revolutions at slow speeds.
Helps with fuel economy
PG – 106
How does the stern power of a ship with a shrouded propeller compare to the same size ship with an unshrouded propeller?
The stern power of the shrouded propeller is very poor in comparison
Pg 112
True or false Twin shilling, Rutters are the same in concept of design and operation to single flap or shaped rudders.
False the system is totally different in design and operation
PG 116
True or false twin schilling, rudders act independent of one another to achieve maximum efficiency
False these writers are synchronized to work in harmony with each other in response to a single joystick control
PG – 116
With a single rudder and a twin screw response time is __________ and realize on what?
Exceptionally poor and vessel speed
Pg 119
When the starboard prop to an O /B turning fixed pitch twin screw prop is put a stern. How does it behave?
A. Like a left-handed prop.
B. Like a right handed prop.
C. No transverse thrust is noted.
D. None of the above
B. Like a right handed prop.
Prop heal discharge goes to the starboard quarter bow goes to starboard
PG – 122
True or false backing one engine is the best way to turn a twin screw vessel no matter what speed.
False this is fine at low maneuvering speeds. It is unwise at moderate speeds. Transverse thrust is a poor force.
Page 127
Where should the towing hook be to increase maneuverability of a tug as much as possible?
A. As forward as possible.
B. Aft close to the prop.
C. It does not matter
A. As forward as possible, this has a tendency to place a conventional tug at risk for interaction or gifting
Pg. 131
What does it mean to bows down or gob down when referring to tug operations?
A. Adjust the length of the gob line.
B. Work hard againt gob line.
C. Turn downstream.
D. To release the gob line.
A. Adjust the gob line
Pg. 138
What option to traditional tugs can be used to assist a turn when Ballard poll cannot be used?
A. Find a bigger more maneuverable tug.
B. Use the power of the tug to maintain position and tugs weight to lay on the tow.
C. Use a gob rope.
D. None of the above.
B. Use the power of the tug to maintain position and tugs weight to lay on the tow.
This can be done on the bow at higher speeds to assist, swinging the bow
Pg 138
When using the tugs weight to assist in return with a traditional tug, which tug is more restricted? Bow/Stern
The stern tug usually resorts to the following on a slack line until speed is reduced to get imposition
PG 138
Where are the two towing positions that an ASD tug is located?
One Forward and one mid ships propulsion is two aid units located after similar to traditional twin screw tag positions
PG – 144
Which tug position should be used with caution because of the healing angle with full side, thrust and backwash and turbulence?
Lashed up alongside backwash and turbulence is due to the close proximity of the hull
PG 147
Which tug position is best when moving a dead ship where the tug can work as a Rutter and propeller?
A. Lashed up tug aft
B. On a hawser forward
C. On a hawser aft
D. Lashed up forward
A. Lashed up tug aft. Should be as far after as possible.
PG Dash 149
When an ASD tug is working position, one it can paravane out as long as the tow line is coming off the bow it does not generate the same force as a tractor tug because of what?
A. ASD lack the BP of a tractor tug
B. ASd has propulsion aft
C. Tractor tug have a larger skeg.
D. None of the above
C. Tractor tug have a larger skeg.
Pg 150
True or false a ship with a good bow thruster can replace a tug up forward.
True. A ship without a bow thruster should have the tug placed close to where the bath thruster should be.
Pg 158
A 1000 KW baluster generates how much force?
1341 SHP or 13 tonnes
Pg 47
.74 kw = 1 shp
True or false It is often more expedient to use backing into a birth as a method for docking star side, two as opposed to bow in
Using a large reserve, power for positioning and control helps much more to control position of the stern and speed
Pg 104
What effect can be used to lift the ship bodily off the dock when backing out?
Wedge effect
Pg 24
CPP clockwise rotation acts like a traditional ______________ handed propeller. CPP counterclockwise acts like a traditional __________ handed propeller.
- Left-handed. Cut the bow to port.
- Right handed cuts the bow to starboard
PG 26
In general, where can the weakest current in a bend be found and what is the drawback to using this side during a turn?
A. Outside of the bend and too shallow for most ships.
B. Inside the bend and to shallow.
C. The middle of the channel in subject to rotary currents.
B. The inside of the band has the weakest current generally is shallow..
PG 77 all right
When may a ship lose the influence of the current in one part of the ship and cause an unexpected turning lever?
A. Passing close to the end of a jetty or shallow area.
B. Passing from shallow water to deep water.
C. Passing the ship at close quarters
D. None of the above
A. Passing the end of a yeti or shallow water, this can be remedied with a healthy kick ahead.
Pg 77 - 80
True or False: If a bow thruster is equal in power to a dead, slow ahead, kick dead, slow ahead should be the only thing used in working a ship laterally
False. More powerful kicks may be useful a compromise at lower power power may be used.
Pg 94 - 96
If the ship is allowed to creep ahead, where does the pivot point move the instant it begins to make headway?
1/8 length from the bow
Pg 104
What 2 forces come in to play when making headway? Where does the pivot point go when making steady speed forward?
- Forward momentum and longitudinal resistance to forward momentum.
- 1/4 L from fwd
Pg 12 - 13
What is SHP?
What is BHP?
Shaft horsepower: the power generated to turn the prop
Break Horsepower: the actual power developed by the engine
Pg 20
An 80,000 deadweight ton ship with full ahead power of 20,000 SHP how much force is applied to the starboard when backing assuming 50% of is applied a stern and transverse thrust 5% to 10%
1,000 SHP or 10 tonnes
100 SHP = 1 ton
Pg 23
Shaft horse power is an important factor in determining the magnitude of transverse thrust. What must also be considered when going astern?
Location of pivot point
Pg 23
When does transverse thrust start to create a turn moment on a vessel?
When it is moving slow enough for the propeller wash to meet the hull
Pg 24
When does the magnitude of transverse force reach its peak when making headway?
What will maximize transverse force?
- Just prior to the ship being completely stopped.
- When stern power is applied it’s at its maximum.
Pg 24
What is the only thing that changes with changes in speed in regards to turning?
Rate of turn
Pg 30
During a turn the exposed side experiences increase in water resistance which acts as a brake. A ship may see _______ % to _______% speed loss during a turn.
30% to 50%
Pg 30
Standing turns and kicks ahead can reduce a turn radius this is because a reduction in _________.
Lateral resistance
Pg 30
When the stern is sweeping to port during a turn in shallow water where does the water pressure build up?
A. Fwd of the pivot point
B. At the pivot point
C. Abaft of the pivot point
C. Abaft of the pivot point. Due to restricted UKC
Pg 33
True or False: If the wind is on the port beam, transverse thrust from a fixed right hand prop may be nullified, depending on the strength of the wind/prop power will determine which way the stern swings (while backing).
False a port beam wind will intensify bow swing to stbd stern to port. Starboard beam wind will be unpredictable
Pg. 41.
At best how much power percentage is used with a kick ahead at full power?
A. 50%
B. 35%
C. 45%
D. 80%
C. 45%
Pg 43
When using lateral motion to walk a crossed the tide this is called?
A. Crab
B. Poor man’s tugboat
C. All of the above.
C. All of the above.
A kick ahead at full power will produce approximately what percentage of sideways thrust?
A. 70% - 80%
B. 10% - 20%
C. 40% - 50%
D. 20%-30%
C. 40% - 50%
If the Main Engine produces 12,000 SHP - 120 T that’s 48 - 60 tonnes of thrust.
Pg 94
What is the weakest link on the ground tackle assembly?
A. The anchor chain
B. The anchor
C. The windlass
D. The Jews harp
C. The windlass
Pg 49
Where would the windlass most commonly fail?
The brake
Pg 49
Safety parameters for dredging anchors include:
A. Cable length not to exceed 1.5 x depth of water
B. Windlass gypsy head speed of 30 ft/min
C. Windlasss designed to lift deadweight of anchor + 4 shackles
D. All of the above
D. All of the above
30 ft / min is .3 kts ship speed over the ground
Pg 50
What is the optimal speed for dredging anchor so that it does not dig in and holds?
A. .3 kts
Pg 50
Dredging anchors is very effective for controlling what two major problems when berthing?
A. Control of heading & speed
B. Control of heading & drift
C. Control of speed & drift
A. Control of heading & speed
Pg. 50
When dredging two anchors where does this bring the pivot point?
Between the two anchors
Pg 50
True or False: even if the vessel with two anchors down may slow or stop the pivot point stays forward and Lateral resistance remains low.
True
Pg 50
What are the three rules of thumb when dredging two anchors?
- Speed must be low
- Max cable depth x 2
- UKS must be 20% of max draft
Pg 51
True or False: Dredging one anchor is easier to control speed then dredging 2 anchors.
False
pg. 53 - 54
When dredging with one anchor where does the pivot point go?
The hawse pipe of the anchor being dredged. And effectively acts like a back spring.
Pg 54
True or False: excessive swings can develop if a helmsman allows too much of the swing in either direction. Sluggish rudders may cause violent sheering and grounding.
True longitudinal pressure forces can be easily brought to an exposed side due to shallow water effect.
Pg 59
What can develop from prolonged use of kick ahead?
A violent sheer or unwanted build up of speed.
Pg 18
Which way does a right hand prop swing coming ahead?
Slight swing to port
Pg 23
True or False the effect of wind making sternway is generally more complex and less predicatable.
True
Pg. 41
Assuming HP is a little over half of the ahead power, how much power will be used for transverse thrust?
10%
Pg 47
When a ship is running with a 1.5 kt current from astern where is teh pivot point if it is running at a considerably higher speed over the ground then the current is running?
Forward, in order to keep the pivot point forward the ship will have to run at a considerable higher speed than the current.
Pg 72
True or False: today’s modern tugs are capable of pulling a fully loaded ship against a tide with a 1.05 depth to draft ration.
False, the force of tide can exceed the BP of todays tugs
Pg 83
If thruster is 10 T and the pivot point is 145 M away from the thruster what is the turning moment?
1450 TM
Pg 90
A gop rope clearly limits the maneuverability of tugs stern under the towline to a relatively small arc. What advantage does it provide?
A. Keeps the stern up to the ship
B. It allows the tug to dig in at suitable slow speeds
C. It moves the pivot point over the Propellers
D. A and B only.
D A and B only. The tug master can slack the rope to reposition and come back on again.
Pg 138
With a ship making way what kind of turning lever does a tug have on the bow?
(Ship 160 m long) (tug 20 T)
A. 40 x 20 = 800 tm
Pg 153
Where is the best position for a tug in an emergency when you need to slow down?
A. On the stern digging in and braking
B. On the bow pushing
C. On the quarter lashed up
D. All of the above
A. On the stern digging in and braking.
Pg 153
A 160 M ship has a tug on the bow and stern (20 T tugs). What is the turning lever for the tugs when the ship is DIW?
Making headway? Making sternway?
A. Stopped FT 80 m x 20 t = 1600 tm
AT 80 m x 20 t = 1600 tm
B. Headway FT 40 m x 20 t = 800 tm
AT 120 m x 20 t = 2400 tm
C. Sternway FT 120 m x 20 t = 2,400 tm
AT 40 m x 20 t = 800 tm
Pg 154
Where is the pivot point when a vessel is stemming the tide moving at a very little speed over the ground but making headway through the water?
Pivot point is forward
Pg 72
When operating against the current and the ship is allowed to drift back where is the pivot point?
Midships
Pg 72
True or False: Crabbing or using the current to create sideways motion can be accomplished by bringing the ships SOG to zero and directing the tide to the appropriate bow with the rudder along.
True. A short kick ahead can be used to ease the tide to stop bring the head back towards the tide.
Pg 72
What may be encountered by using the bow thruster?
A small amount of headway. A buildup of positive water pressure along the ship’s side which creates water flow around the bow causing low pressure ahead of the ship
Pg 93
What is true concerning twin schilling rudders?
A. This system is incredibly complicated and hard to learn.
B. This system is a little strange at first but after some instruction it’s picked up relatively quickly.
C. This system is the same as a conventional rudder system.
B. This system is a little strange at first but after some instruction it’s picked up relatively quickly.
Pg 118
True or False some twin screw props are designed well beyond the fore and aft line of a ship if this is the case the master may have to stop the inboard propeller while coming close to the dockside.
True
pg 121
True or False:
The effect of inward turning fixed pitch propellers upon a ship is extremely severe and unmanageable from a shiphandling prospective. Often one engine is stopped and maneuvered like a single screw.
True.
Pg 124
Transverse thrust is more noticeable with _____________.
A. Ahead movement
B. Astern movement
C. Equally noticeable
B. Astern movement
Pg 23
Which movement of the ship is of greater significance to teh ship handler when considering transverse thrust?
Astern movement
Pg 23
True or False: The large superstructure and funnel of a vessel is the only thing to consider when estimating the effect of wind on a ship.
False. The freeboard forward of the house to the bridge should also be considered
Pg 38.
True or False: The center of wind is sometimes much farther forward than expected.
True
Pg 38
True or False. Small increases in wind speed mean small increases in wind strength.
False. They can mean large increases in wind strength. Gusting can have an enourmous strain on a ship.
Pg . 43
Large full bodied ships have ___________ turning circles. (Poor or good)
Good, mall lined ships have poor turning circles
Pg 36
True or False the same ship doing a full ahead and slow ahead turn will create virtually the same turning circle for 20º and 35º turns.
True. Pg 27
When a vessel is backing down and intending to work the ship to starboard and checking the swing on the bow with the thruster what can be an unintended consequence?
The ship sets itself to port with the bow operating bow thruster and the stern transverse thrust.
Pg 96
When is the bow thruster most efficient?
A. When working astern
B. When the ship is stopped
C. When working ahead
D. A and B only
D. A and B only
Pg 96
What is the maximum angle a Becker rudder will give you when the helm is put hard over?
70º
This adds much more turning ability over the conventional rudder.
Pg 115
The maximum rudder angle for twin schilling rudders is what?
110º
Pg 116
By splitting the engines of a twin screw propeller system in a turn where does the pivot point go? What happens as the vessel gets headway or sternway?
- 1/8 L of the bow permanently.
- The pivot point moves aft
Pg 125
What is the best way to turn a twin prop vessel at moderate speeds?
A. Put one engine astern and one engine ahead w/hard over rudder.
B. Hard over rudder with sufficient power kicks ahead.
C. Hard over rudder.
D. Both engines astern.
B. Hard over rudder with sufficient power kicks ahead.
This results in a much tighter turning circle.
Pg 127
When a tug takes the weight of the tow where does the pivot point go? What happens to the turning moment?
A. After and is reduced
B. Stays the same and stays the same
C. After and increases
D. Fwd and increases
A. Aft and is reduced
Pg 131
What is the safest practice for tug approaching a ship from the stern?
A. Approach at full speed
B. Have the vessel slow down
C. Have the vessel stop engines
D. Approach at slow speed
C. Have the vessel stop engines. The tug mast should be fully informed as to the status of the ship’s propulsion.
Pg 134
Where is the best place for a tug to be to prevent gifting?
A. 1
B. 2
C. 3
A. 1
Regardless of the ship speed it has a small angle on the bow position 2 may be out run with too much speed or stbd helm position 3 is the worst it is pulled along the radius of the towing line.
Pg 136
Which position is the best for a conventional tug on the stern? What is the worst most risk in girting?
A. 1
B. 2
C. 3
A. 1 is the best and most effecient for a conventional tug with max bollard pull in all directions
Position 2. The tug keeps in the heading and has a tendency to get the tow line on the bow.
Position 3 is the worst position tug dragged around the radius.
Pg 136
These two things should be remembered if a conventional tug is working forward.
- The risk of girting is increased and the tug master must keep a close eye on ship’s speed.
- Tugs may imapart an insidious increase in speed to the ship which needs to be monitored
Pg 140
True or False: the tractor tug suffers from a lack of directional stability when steaming at speed without a tow.
True
Pg 142
What are the advantages of tractor tugs? 10 things
- Full thrust 360º
- Rapid power on response
- Outstanding maneuverability
- Able to reposition quickly
- Simple control systems
6.very low risk to girting - Can more effectively overcome interactive forces
- Improved operational capability in a restricted area such as enclosed dock
- May decrease the turn around time of port movements that use tug assist
- Reliable robust prop units
Pg 142
What are the disadvantages of tractor tugs? 8 things
- High capital investment costs
- Less bollard pull per KW power
- Repair and maintenance of complex underwater units may be expensive
- Handling in open seaway might be poor with the short distance between pivot point and thrust creating a short turning lever
- Heeling angle with full thrust may be up to 21º with some tugs. There fore risk of damage can exist when laying alongside a ship
- Sophisticated underwater units may damaged or grounded
- Draft may be up to 5 meters, which is large in comparison to conventional tugs
- The re-training of conventional tug masters in order to fully max a tractor tugs potential
Pg 144
What are the advantages of ASD tugs? 6 things
- Better directional stability at speed
- More suitable hull form for open waters and working in a seaway
- Improved bollard pull per KW power
- Azimuth units easy to withdraw for maintenance and repair
- Maximum heel with side thrust less than 15º
- Shallower average draft of 3m
Pg 144
What are the disadvantages of ASD tugs? 6 things
- Side stepping ability not as good
- Squat at the stern and flooding of the aft deck has been known to occur with certain design types when backing full power
- Still susceptible to girting from effects of interaction
- It is not uncommon for 99% of all towing to be limited to fwd position
- Complex control systems
- More susceptible to rubbish damage in propellers.
Pg 144
Note on Tractor Tugs
Position 1 and 2 if the ship’s speed is sensible it can assist in swinging and positioning this is similar to a conventional tug.
Position 3 shorten but retaining the tow line, this will give it more push pull position during breasting.
Note tractor tugs working tug fwd
Position 1 is good for lifting off from the berth and can move in to push or check ship’s speed.
Position 2 is lashed up alongside is used in lifting off with a lot of power.
Pg 147
What is paravane effect?
A. Tug on a hawser aft uses its weight and water pressure to assist in swinging and steadying
B. Tug on a hawser aft direction pull aft
C. Tug aft quarter pushes or pulls
D. Tug on the bow shoulder uses its weight and drag to turn the vessel.
A. Tug on a hawser aft uses its weight and water pressure to assist in swinging and steadying.
Also known as indirect towing.
Pg 149
When in indirect towing mode the pull on the tow line can increase by a factor of ________ to ________ times the bollard pull.
1.5 to 2 times
Pg 149
These are questions you should ask when positioning a tug. 5 things
- What is the intended movement or maneuver?
- Will the ship be predominantly with headway?
- Where will the ship’s pivot point be?
- Where will the tug be in relation to the ship’s pivot point?
- What type of tug being used?
Pg 150
What are some reasons to require a tug escort?
A. Wind, current, ship size or shallow water or a combination exceeds the ship’s normal turning ability
B. Legislation requires it based on previous accidents or pollution
C. Serious equipment failure of ship
D. All of the above
D. All of the above
Pg 153
What is the benefit of having a tug forward when the vessel has fwd momentum?
A. Best place to assist in swinging the vessel
B. This is an ideal place to help brake and stop up
C. Most effective spot to create lateral movement
D. All of the above
C. Most effective spot to create lateral movement
Coupled with hard over rudder and kicks ahead.
Pg 156
When using an anchor to turn short round and it doesn’t seem to have the desired effect what should the first move be?
Let out more chain
Pg 76
Where does the pivot point go when going astern?
1/4 L from the stern
Pg 12 - 13
Trim in which direction will change a vessels wind handling characteristics? (While moving fwd with headway)
Trim by the stern with a pivot point close to the wind point wind effects the turning lever is reduced.
Pg 41
Rudders that include flaps, rotors or rotors with flaps are called what?
Becker rudders also jastram rudders
Pg 115
A rudder where the top and bottom is constructed with flanges which helps channel water flow across the rudder face as it run into the concave section before being deflected at a sharp angle at the end is what?
C. Single schilling rudder
Pg 115
Single schilling rudders and Becker rudders that are capable of 70º are used like conventional rudders they have one advantage which is?
A. Excellent turning ability
B. Excellent fuel economy
C. Excellent response time
D. Excellent backing power
A. Excellent turning ability when used in combination with the bow thruster the lateral motion with kick ahead can be even too excessive.
Pg 115
When handling a twin screw ship at moderate speeds the following is true?
A. Transverse thrust is a good turning force
B. Transverse thrust wash will not reach the hull if the speed is too high
C. Rudder force generated with ahead power is a poor turning force.
D. Correctly applied kicks ahead will not be the most effective way to tighten a turn.
B. Transverse thrust wash will not reach the hull if the speed is too high.
Every thing else is opposite
A. Transverse thrust is a poor turning force
C. Rudder force generated with ahead power is a good turning force
D. Correctly applied kicks ahead is the most effective way to tighten a turn.
Pg 127
What is the formula for calculating wind speed in meters / second from knots? What is the formula for calculating wind force in tonnes?
V = wind speed in meters/second
V = wind speed in knots / 2
Force (tonnes) per 1000 m2 = V2 / 18
Pg 43
Ship’s length is 280 m, freeboard is 25 m what is the total wind area?
280 x 25 = 7000 sq m
Pg 160
Which statement is true concerning a bow thruster?
A. Thruster is always fast coming to full power
B. The ship will steer sluggishly with a tendency to flop to either side
C. The thruster will be quick to correct ROT
D. Looking astern ROT is easily perceived
B. The ship will steer sluggishly with a tendency to flop to either side
The thruster may be slow coming to full power.
The thruster may be slow to correct ROT
Looking astern ROT is not easily perceived
Pg 99
A 200 m ship with a 12,000 shp main engine will use how much of this to go astern power? How much will be transverse thrust?
60% ahead and 10% transverse thrust
720 shp or 7 tonnes
Pg 99
True or False shrouds are especially effective at low speeds and high loads at zero fwd speed and full power about 50% of thrust comes from the duct.
True
pg 110
What happens to the water flow a crossed the rudder when angles that exceed 45º are put on the rudder?
It is progressively turbulent until the rudder stalls out is much less effective
Pg 115
How does a joystick control work with twin schilling rudders? Full ahead? Bow to port? Full astern? Stop engine? Astern?
Full ahead: joystick fully forward as eased back open outwards to reduce speed.
Bow to port: joystick forward and to port one rudder 70º and one is 35º
Full astern: joystick is pulled back until rudder rotates to 110º closing gap between
Stop Engine: achieved by adjusting the joystick to appropriate intermediate neutral setting
Astern: stern to port when operating full aster backing or slowing joystick is eased to port quarter control bow with kicks ahead.
Pg 118
If the wind is on the port beam how much does this effect transverse thrust when backing with a fixed right hand prop? What is the best way to overcome it?
- It will be nullified.
- Overcome with kicks ahead
If the winds over ride the power of the bow thruster and attempting to back down what should be done?
Do not attempt to back down
Pg 103
What can be done when backing down to limit transverse thrust?
Take every opportunity to stop the engine and keep the pivot point aft.
Pg 103
How should the ship be angled to allow for transverse thrust?
Bring the stern around sufficiently to allow for transverse thrust.
When backing down how often should you used the bow thruster?
As often as need to boldly and vigorously steer to keep the stern on an inter track.
What are two advantages to backing a ship to a berth and using engine power?
- You can correctly position the stern
- You can check the stern speed and keep it to a minimum.
Pg 104
True or False it is unwise to use kick ahead with full stbd rudder if the ship is starting to creep ahead because you may never get back in position when going stbd side to the dock.
True
Pg 104 the stern will swing to port.
When going stbd side to with a left hand cp propeller which direction will the natural flow of water go when approaching or departing?
Along the stbd side pushing off the dock. This is coming ahead.
What is true about a tug aft when backing into a berth?
A. It is best placed to help develop bodily lateral motion
B. It will be useful in lifting the ship off the dock
C. It is not the best position to turning
D. All of the above
D. All of the above
Pg 158
As the ship slows down when approaching a berth with the wind upon or abaft the beam the effect of twine will be:
A. Staying the same
B. Progressively greater
C. Decreasing
B. Progressively greater. As the vessel slows the pivot point moves forward and the turning lever is greater.
Pg 38
True or False when approaching a berth with the wind dead ahead it is much easier to control vs. wind on the beam.
True
Pg 41
What is the best way to back into a berth when going starboard side to when considering stern placement?
Keep the stern close to the berth. Keep the heading so that it leaves sufficient distance to work alongside this tendency can then be used to swing the ship forward of the pivot point towards the berth and keeps the pivot point back when using the thruster.
Pg 103
When going starboard side to a berth and approaching with the bow what may be the best way to dock?
A. Run past the berth and back in
B. Continue straight into the berth
C. Dredge the port bow anchor as you approach
D. None of the above
A. Run past the berth and back in.
Pg 104
True or false when working aster to a berth a good idea may be to get the ship moving smartly aster initially and keep it moving.
True this avoids lingering under the effects of leeway at slow speeds. Use kick ahead with caution they can take the way off of a ship.
Pg 103
When the ship is dead in the water with little or no outside forces and fwd movement is initiated where is the pivot point?
1/8 L from the bow
Pg 27
When a ship begins to build up speed ahead the water resistance ahead of the ship balances fwd power and pushes the pivot point back to this spot?
1/4 L from the bow
Pg 27
True or false when turning at a steady speed the rudder becomes progressively less efficient.
True the turning lever is reduced.
Pg 27
If a relatively large ship is turning in the bend of a tidal river where should the stern be positioned and where should the bow be positioned to take advantage of the best turning lever?
Stern positioned in the strong current
Bow positioned in the weak current
Pg 77
If a vessel is in a situation with a large turning lever in a tidal river what actions can be taken to aid in the turn?
Kicks ahead with full power.
Pg 77
Propeller wash from tugs can enhance the ________ pressure area between a jetty and ship causing even more _________ that can result in the vessel going aground.
- Low
- Suction
Pg 80
When the ship is stopped and the bow thruster is activated where does the pivot point go?
Ship’s width from the stern
Pg 90
When making way with turning the pivot point moves to where? This results in a _______ turning lever if trying to use the bow thruster.
- 1/4 L from the bow
- Small
Pg 93
A standing turn using kicks ahead where is the pivot point. What kind of turning lever does it have?
- 1/8 L
- Large
Pg 93
If the ship is allowed to wonder off the intended course what is the first action to take when working astern?
A. Use a bold and vigorous bow thruster power
B. Use a kick astern
C. Use a kick ahead
D. Stop the engine and use small bow thruster corrections
A. Use a bold and vigorous bow thruster power
Consider the effect of transverse thrust
Pg 99
True or False if on a CP prop ship the sod is not reduced slowly and progressively the rudder will be shielded and steering may become erratic and poor.
True
Pg 107
What is true concerning the shroud on a propeller?
A. It will improve the quality of steering
B. It will improve response to kicks
C. It may give better directional stability
D. All of the above
D. All of the above
Pg 112
How much transverse thrust will a shrouded propeller see when backing?
Very little or no transverse thrust. The ship will run in a relatively straight line.
Pg 112
How is lateral motion used to maneuver to a berth with the tidal current from ahead?
It is put fine on the bow and wait to see if it takes the desired effect. If a big angle is taken it may take too much time and room to maneuver back into the tide.
Pg 72
Where is the pivot point when the ship is working astern?
1/4 L from the stern
Pg 98
True or False
With stern power, hull design and transverse thrust varying from ship to ship. Transverse thrust is still considered a relatively poor force.
True. Because of the short turning lever.
Pg 99
True or false the kinetic energy that develops with a ship threat is allowed to drift sideways when backing down the channel is more pronounced on vessels with larger tonnage.
True
Pg 100
The basic rudder is not hydrodynamic efficient beyond what rudder angle?
35º
Pg 112
What is the greatest enemy to work against you when turning a twin screw vessel?
A. Excessive speed
B. Squat
C. Bank effect
D. Transverse thrust
A. Excessive speed
Pg 127
When a ship is at a stop or suitable slow speed and a kick ahead is used where does the pivot point go?
Pivot point moves well forward
Pg 36
What is drift angle?
The angle between the ship’s head and the direction the bridge (aft) is traveling.
Pg 36
Is it more obvious when the ship’s speed is too slow or too fast? What can be adjusted easier?
- Too slow
- Slow can be adjusted easier
Pg 16
When a ship develops forward headway where do the center of wind and pivot point go?
- Wind stays the same
- Pivot point moves forward
Pg 38
True or False it is likely that transverse thrust power will be overcome by most wind speeds.
True. Transverse thrust is a weak force against most wind.
Pg 47
In calm conditions and still water what point does the pivot point coincide with and where?
- Center of Gravity
- Midships
Pg 12
True or False:
A kick ahead should only be used at full power to achieve the desired effect.
False, slow head can be used on smaller ships. Full power may be needed on VLCCs to get the desired effect.
Pg 20
With a 26, 000 DWT ship with 6,000 SHP astern what is the transverse force working on the starboard quarter going astern? What is the turning moment with fwd movement (pp 110 m away)?
Transverse thrust 10% of 6,000 is 6 tonnes
Turning moment 6 tonnes x 110 = 660 tm
Pg 24-25
At a steady speed while turning the pivot point is here?
1/2 L from the bow
Pg 27
The balance between __________ force and _________ plays a crucial part in shaping all turning circles.
- Rudder force
- Lateral resistance
Pg - 27
Rudder Force try’s to do two things what are they?
- Turn the ship
- Drive the ship forward
Pg 27
When a ship starts a turn from DIW what initially resists the ships tendency to come ahead?
Ship’s inertia
Pg 27
The large build up of water along the ship’s side which apposes rudder force in a turn is called what?
Lateral resistance
pg 27
After ______º of a turn care should be given as the ship may start to build up again as rudder force and lateral resistance return to normal.
90º
Pg 30
Where is the best turning moment achieved while using the bow thruster?
A. When stopped
B. When coming ahead
C. When a coming astern
D. When in a constant RPM turn
A. When stopped
Any headway or stern way will move the pivot point and shorten the lever.
(Pp is at 1 W from the stern when stopped)
Pg 90
In shallow water where does the pivot point moved due to the build up of longitudinal resistance?
A. Back towards the center
B. Fwd to the bow
C. Back to the stern
A. Back towards the center due to an upset in the imbalance of fwd momentum and longitudinal resistance
Pg 33
Ship’s with the ability to have large drift angles have _______ turning circles.
Good , finer lined ships do not have large drift angles and have poor turning circles.
Pg 36
Even in a weak tide if a ship blocks the tide between it and a jetty it causes what? Resulting in what?
- Low pressure
- Resulting in more suction toward the jetty.
Pg 80
You should always avoid ________ angles when passing jetties to avoid suction to the bank.
Acute
Pg 80
A depth to draft ratio of 1.05 the tidal force is _______ times stronger than a draft ratio of 3.0.
3 times
Pg 81
Except for a few powerful units performance of the bow thruster will fall off quite rapidly after the ship’s speed rises above _______ kts.
2 kts , high speed turbulence through the entrance tunnel impairing performance externally water flow deflects thrust output.
Pg 93
Twin CPP handed propellers refers to what?
I/B turning props.
O/B turning cp props are very uncommon and be used like a single screw ship.
Pg 124
True or False: Full bodied ship’s like bulk carriers are difficult to ship handle because of their inability to generate lateral motion.
False, these ships have large drift angles and the lateral motion they generate can be used to advantage.
Pg 36
With a ship initially stopped where is the center of a beam wind in comparison to the pivot point?
Amidships
Pg 38
In general which is more effective against a wide range of wind strengths, kicks ahead with full power or bow thruster power.
Kicks ahead with full power
Pg 47
If it takes 15 min to turn a ship short round in a 2 kt current, how far will it have moved over the ground in that time?
.5 nm
Pg 70
If a ship finds itself rounding a bend where the bow is in a stronger current and stern is in a weaker current what action should be taken?
A. Use appropriate helm and power
B. Hard rudder only
C. Stop engines
D. Drop the appropriate anchor
A. Use appropriate helm and power
Pg 77
The force of the tide upon a ship is directly proportional to the _________ of the ________ of the tide.
- Square
- Velocity
Any smaller increase in velocity has a much larger increase in force.
Pg 81
What are the two aspects that need to be monitored when using a thruster while stopped?
- Unexpected movement ahead
- Position of the pivot point
Pg 90
When interacting with a bank which has a larger turning lever?
A. Bow cushion
B. Stern suction
B. Stern suction
On the greatest turning lever with the pivot point closer to the bow.
Pg 55
What causes low buoyancy in a vessel moving into shallow water?
A. High pressure created by high speed water moving under the bow
B. Low pressure created by high speed water moving under the bow
C. Low pressure created by high speed water moving along the side of the ship
D. None of the above
B. Low pressure created by high speed water moving under the bow.
Pg 55
When a vessel squats in shallow water what happens to the steering lever and pivot point?
Pivot point moves back and steering lever is reduced
This is because of the build up of water on the bow and increase in longitudinal resistance.
Pg 55 - 59
General ship’s squat by the __________ when moving into shallow water.
Head
Pg 59
True or False: The ship’s wave system catching a ship up as it slows in shallow water, may affect trim for a short time and enhance sinkage at the bow.
True
Pg 59
Why does a ship lose rudder efficiency in shallow water?
A. Rudder force has to overcome a larger amount of lateral resistance
B. A larger amount of pressure builds up on the bow because of reduced UKC
C. The pivot point gets pushed back
D. All of the above
D. All of the above
Pg 33
True or False a ship maneuvering through a large turn in shallow water may experience an increase in draft due to list.
True . Due to an increase pressure along the side which the ship is turning this results in an increase flow of water under the ship this produces a low pressure under the ship.
Pg 33
True or False: When meeting in a narrow channel it is essential to move over to your side of teh channel as close to the edge as soon as possible.
False, working over too soon may cause an unexpected sheer acrossed the path of an approaching ship.
Pg 60
What are two possible causes for a ship under sternway cutting the wrong direction in close proximity of solid jetties, banks or shallow water?
- Wedge effect - excessive stern power creates was between the ship and obstruction this may be enough to swing the bow to port.
- Shallow water effect flow of water is being deflected.
Pg 24
At what depth of water is considered shallow water?
2 x the draft or less.
Pg 55
Shallow water may be experienced when the depth of water is less than _______ the ship’s draft.
2 times
Pg 33
True or False as vessel A overtakes vessel B. Vessel A will have a tendency to turn towards vessel B. When the bows high pressure comes into vessel bs low pressure full rudder and power should be used to counter act.
True
Pg 64
True or False: when two ship’s are interacting in an overtaking situation and are abeam of one another a strong turning lever exist. In the low pressure midship and high pressure bows turning away from each other, powerful force and correction is needed to overcome.
True
Pg 64
As two ship’s pass abeam when one is overtaking the other, a powerful suction exists and will draw the ship’s together the overtaken ship may be dragged with the overtaking ship. How do you break the suction?
A. Both ship’s increase speed
B. Bother ships turn away from each other
C. Both ship’s slow down
C. Both ship’s slow down.
Pg 64
What two forces will a ship being overtaken in a narrow channel experience when the two ships are abeam of each other?
A. Squat and bank suction
B. Bank effect and low pressure area of the overtaking vessel
C. Bank effect and high pressure area of the overtaking vessel
Bank effect and low pressure in the area of the overtaking vessel. Creates a turning force.
Pg 64
In an overtaking situation in a narrow channel what adverse effect can the overtaken vessel have on the overtaking vessel?
A. Overtaking vessel experiences a speed up
B. Overtaking vessel can turn unexpectedly across the path of the overtaken vessel
C. No adverse effects felt
B. The overtaken vessel can turn unexpectedly across the path of the overtaken vessel due to the positive pressure from the overtaken vessel
Pg 64
In an overtaking situation in a narrow channel which vessel will probably experience a speed up?
The overtaken vessel
Pg 64
What actions should be done when two ships are going to interact in a narrow channel?
- Prior to the maneuver bother ships should stay in center for as long as possible
- Speed should be reduced to reduce interactive forces
Pg 68
True or False
When ship’s are about to interact engines should be brought to dead slow ahead so that power is instantly available to control with kicks ahead.
True, this is especially important with turbine or fixed pitch propeller ships.
Pg. 68
What might a tug experience when approaching from the stern?
A. An increase in speed
B. A sudden sheer toward the stern of the ship.
C. Less water resistance ahead
D. All of the above
D. All of the above.
Pg 134
Where is the riskiest place for a conventional tug to work?
On the stern
It is frequently obliged to lay with the tow line much more inclined toward the beam.
Pg 136
What are five things that a traditional tug may be at a disadvantage compared to a tractor or ASD?
- Interaction
- Girting
- Excessive ship speed
- Confined locks and dock areas
- Traditional maneuverability
Pg 138
The directional stability of a tractor tug can be improved by what feature?
A large skeg
Pg 142
What best describes a combination or combi tug?
A. A combination of tractor tug and ASd tug
B. Traditional tug retrofitted with a thruster system forward
C. An ASd stern drive tug with a thruster fwd
D. Two thrusters forward like a tractor and one aft centerline
B. Traditional tug retrofitted with a thruster system forward
This could be anything from a thruster system fwd or a tunnel thruster to an azimuth thruster unit that will improve handling characteristics.
Pg 144
When placing a tug for maneuvering what is the most important factor to consider?
A. Where the tug will be in relation to the ship’s pivot point
B. How powerful the tug is
C. Where the pivot point of the tug is
D. What kind of tug is available
A. Where the tug will be in relation to the ship’s pivot point
Pg 150
What statement is true about a ship underway and a tug placed aft?
A. It is likely to be some distance from the pivot point of the ship
B. It is best placed to increase or decrease the ship’s rate of turn
C. It is likely very close to the pivot point working on a small turning lever
D. A and B only
D. A and B only
Pg 158
