Transcript
INTRODUCTION TO SHIPHANDLING
I. ForcesII. Terminology
III. Standard Commands
FORCES
• To understand shiphandling, we must first look at all the forces that affect a ship.
Controllable:
•Engines•Rudder•Lines•Anchor•Tugs•Auxiliary Propulsion
Uncontrollable:
•Wind
•Current
•Shallow water effects
ENGINES
• Power train: power source turns a shaft (through reduction gears), which turns a propeller
• Propellers may be fixed or controllable pitch:– Fixed: Ship speed is controlled by
shaft rpm only– CPP: Ship speed is controlled by both
shaft rpm and propeller blade pitch
ENGINES
• Almost all Navy ships have one of three propulsion plants:– Gas turbine (requires CPP): most
surface combatants– Diesel: Large auxiliaries, minesweepers– Steam (Conventional or Nuclear): Older
ships, aircraft carriers, submarines
SIDE FORCE
• In addition to fore and aft thrust, propeller rotation also causes what is known as “side force”:– Side force is a lateral force caused by
propeller rotation.– The direction of the force is the
direction in which the propeller would “walk” along the bottom due to its rotation.
SIDE FORCE
Standard propeller rotation for single and twin screw ships (ahead operation)
SIDE FORCE
AUXILIARY PROPULSION
• Bow thruster– Hull-mounted, transverse propeller
used to develop lateral thrust when pierside
– Normally found on larger ships• Auxiliary Propulsion Unit (APU)
– Retractable, omni-directional propulsion unit
– Emergency propulsion for single-screw ships
– Can be used for pierside maneuvering
RUDDERS
• Configuration: normally one rudder for each propeller, mounted directly astern of the propeller.
• Range of motion: 35° left or right of CL– Hard rudder: 35°– Full rudder: 30°– Standard rudder: 15°
RUDDERS
• Rudder effectiveness is dependent on flow velocity over the rudder surface.– “Bare steerageway” is the minimum
speed at which a rudder is still effective. This is generally 2 to 3 knots for most ships.
• Rudder angles must be reversed for astern operation
MOORING LINES
• Lines are used next to a pier to control ship positioning.
• General terms:– Breast line: limits lateral motion– Spring line: limits fore/aft motion
• Each line has a specific name, indicating location, direction, and purpose
• Lines are numbered, fore to aft, based on location on the ship.
MOORING LINES
1 - Bow line
2 - After bow spring line
3 - Forward bow spring line
(No number) - Breast line
4 - After quarter spring line
5 - Forward quarter spring line
6 - Stern line
TUGS
• Used to assist ships in pierside maneuvers
• Three ship-to-tug tie-ups are used:– Single headline: Simple; effective for
steady pushing/pulling in one direction– Double headline:Allows tug to push
the ship both ahead and astern– Power: Best general purpose tie-up;
allows tug to use engines and rudder in any direction without moving itself
• Pictures are shown on the next slide.
TUGS
SHALLOW WATER EFFECTS
• Increased resistance: In relatively shallow water at high speeds, pressure drag on the hull is significantly increased, resulting in actual speed less than ordered speed.
• Squatting: The ship’s bow wave is increased, resulting in a lifting of the bow and sinking of the stern.
SHIP TERMINOLOGY
• Bow• Stern• Forecastle• Hawsepipe• Weather
decks• Draft• Freeboard
• Superstructure
• Pilothouse• Mast• Yardarm• Truck• Stack• Keel
•Shaft
•Propeller
•Rudder
•Stern
•Transom
•Waterline
SHIPHANDLING TERMS
• Turning Circle - Path followed by the ship’s pivot point in a constant turn
• Pivot point - The point on the CL about which the ship pivots in a turn– Typically about 1/3 of length abaft the bow
• Advance• Transfer
SHIPHANDLING TERMS
• Tactical Diameter - Perpendicular distance between the path of the ship on original course and final course after a 180° turn
• Standard Tactical Diameter - Tactical diameter prescribed by current tactical orders for formation maneuvers
• Reduced Tactical Diameter - Diameter obtained at full rudder using standard speed
SHIPHANDLING TERMS
• Final Diameter - Diameter of the ship’s turning circle
• Kick - Momentary movement, at the start of a turn, of the ship’s stern toward the side opposite the direction of the turn
• Surge - Distance gained/lost during a speed increase or decrease
SHIPHANDLING CHARACTERISTICS
STANDARD COMMANDS
• We have previously discussed the role and importance of the Conning Officer.
• To avoid any possible confusion between the Conning Officer and the Helm or Lee Helm, all steering and engine orders are given using standard phraseology and format.
HELM/LEE HELMCONNING OFFICER
CommandReply
Report
Acknowledgement
FORMAT
HELM CONSOLE
ENGINE ORDER TELEGRAPH
MODERN HELM CONSOLE
COMMANDS TO THE HELM
Format Example
-Direction "Right. . .""Left. . ."
-Amount ". . standard rudder. . ."". . .ten degrees rudder. . ."
-Course ". . .steady course two zero zero."". . .steady on course one one five."
COMMANDS TO THE HELM
• Direction: Either left, right or “Rudder amidships”
• Amount: Expressed as a number of degrees of rudder (10, 15, etc.), or one of the following: (nominal values given)– Standard: 15°– Full: 30°– Hard: 35°(maximum rudder angle)
COMMANDS TO THE HELM
• Direction and rudder angle together comprise the first portion of the command.– “Right ten degrees rudder”– “Left full rudder”– Two exceptions to the phraseology:
• “Rudder amidships”• Hard rudder: “Hard right rudder” instead
of “Right hard rudder”
COMMANDS TO THE HELM
• Course to steer: This portion of the command is not required. If not given, the Helm maintains the rudder at the ordered angle until another order is given.– “Steady course ___”– This order tells the Helm to adjust the
rudder and steady on a final course.
COMMANDS TO THE HELM
• Exception: Course changes of 10° or less:– For small course changes, a specific
rudder angle is not given. This allows the Helm to use up to 10° of rudder to make the course change.
– The standard command is:• Direction: “Come right/left”• Course to steer: “Steer course ___”
COMMANDS TO THE HELM
• Examples:– “Right standard rudder, steady course
260”– “Left 15° rudder”– “Rudder amidships”– “Come right, steer course 158”– “Hard left rudder”
OTHER HELM COMMANDS
• Desired action: Increase or decrease rudder angle from a previously ordered angle
• Command:– “Increase your rudder to ________”– “Ease your rudder to _______”
• Note: Anytime a new rudder angle is ordered, a steering/steady course must be repeated if it is desired.
OTHER HELM COMMANDS
• Desired action: Change rudder angle to an equal amount of rudder in the opposite direction
• Command: “Shift your rudder”• Note: Again, if desired, course to
steer must be repeated.
OTHER HELM COMMANDS
• Desired action: Steady the ship on the current heading
• Command: “Steady as she goes”– When given, the Helm immediately
determines ship’s head at the instant of the command, and steadies the ship on that course.
– This should normally be given only with the rudder at or near amidships.
OTHER HELM COMMANDS
• Desired action: Determine current ship’s heading
• Command: “Mark your head”– When given, the
Helm immediately determines ship’s head at the instant of the command,and reports it to the Conn.
• Desired action: Warn the Helm to steer more exactly
• Command: “Mind your helm”
HELM REPLY
• Whenever an order to the Helm is given, the Helm repeats the order back to the Conn verbatim.
• This assures the conning officer that the order was heard and understood correctly.
HELM REPLY
• Examples:– The Conn orders: “Right standard
rudder, steady course 260.”– The Helm replies: “Right standard
rudder, steady course 260, aye.”
HELM REPLY
• Order: “Mark your head”• Reply: “Mark my head, aye. 283.”
• Order: “Mind your helm”• Reply: “Mind my helm, aye.”
HELM REPLY
• If the helm does not understand an order from the Conn, the helm will reply:“Orders to the helm”
• The Conn should immediately check his/her order and restate it clearly to the Helm.
REPORT & ACKNOWLEDGEMENT
• Once a desired action is complete, the Helm reports it to the Conn.
• The Conn acknowledges all reports with “Very well’
• If the Conn does not acknowledge a report, the Helm should repeat the report until acknowledged.
EXAMPLES
Order: “Right standard rudder, steady course 298.”
Reply: “Right standard rudder, steady course 298, aye.”
Report: “Sir, my rudder is right standard, coming to new course 298.”
Report: “Sir, steady on course 298, checking 309.”
EXAMPLES
Order: “Come left, steer course 345.”Reply: “Come left, steer course 345,
aye.”Report: “Sir, my rudder is left 5°,
coming to new course 345.”Report: “Sir, steady on course 345,
checking 352.”
EXAMPLES
Order: “Right full rudder.”Reply: “Right full rudder, aye.”Report: “Sir, my rudder is right full,
no new course given.”Report: “Passing 230 to the right.”Order: “Belay your passing heads.”Reply: “Belay my passing heads,
aye.”
EXAMPLES
Order: “Ease your rudder to right 15°.”Reply: “Ease my rudder to right 15°,
aye.”Report: “Ma’am, my rudder is right 15°,
no new course given.”Order: “Steady course 143.”Reply: “Steady course 143, aye.”Report: “Ma’am, my rudder is right 15°,
coming to new course 143.”
EXAMPLES
Order: “Hard left rudder.”Reply: “Hard left rudder, aye.”Report: “Sir, my rudder is left 35°,
no new course given.”Order: “Shift your rudder.”Reply: “Shift my rudder, aye.”Report: “Sir, my rudder is right 35°,
no new course given.”
EXAMPLES
Order: “Right full rudder.”Reply: “Right full rudder, aye.”Report: “Sir, my rudder is right 30°, no new
course given.”Order: “Rudder amidships”Reply: “Rudder amidships, aye.”Report: “Sir, my rudder is amidships, no
new course given.”Order: “Steady as you go.”Reply: “Steady as you go, aye. Course 098.”Report: “Steady on course 098, checking
107.”
ENGINE ORDERS
• For fixed pitch propellers, ship speed is dependent on shaft rpm only.
• For controllable pitch propellers, ship speed is dependent on shaft rpm and, below about 12 knots, propeller blade pitch.– For gas turbines, the shaft is always
spinning when the engine is on line. “All engines stop” is achieved by a blade pitch of 0°.
ENGINE ORDERS
• Prescribed standard speeds are predetermined ship’s speeds:– “Standard speed” - normally 15 knots– “1/3” - one third of standard speed– “2/3” - two thirds of standard speed– “Full” - speed higher than standard
speed– “Flank” - maximum speed
ENGINE ORDERS
• AheadBell Speed1/3 52/3 10Std 15Full 20Flank Max
speed
Typical Prescribed Standard Speeds
• AsternBell Speed1/3 52/3 10Full Max
speed
ENGINE ORDERS
Format Example
-Engines ”All engines. . ."
-Direction ". . ahead full. . ."
". . .back 2/3. . ."
-Speed ". . indicate 108 revolutions for 15 knots."
". . .indicate 072 revolutions and 20% pitch for 3 knots."
ENGINE ORDERS
• Engines: Port, starboard, or all engines. Unnecessary for single screw ships.
• Direction: Ahead, back or stop, and nearest standard speed (except for stop)
ENGINE ORDERS
• Speed: “..indicate ____ turns for __ knots.”, OR“..indicate turns for __ knots.”– For controllable pitch propellers below
12 knots:“..indicate ___ turns and __% pitch for __
knots.”OR, “..indicate pitch and turns for __
knots.”
MANEUVERING COMBINATIONS
• In maneuvering situations, where frequent engine changes are expected, the Conning Officer may set “maneuvering combinations”.
• When set, the Lee Helm answers all bells at the prescribed standard speed increment.
• On ships with an EOT, this is indicated by an RPM setting of “999”.
REPLIES AND REPORTS
• Reply: Verbatim repeatback is required.
• Reports: Lee Helm reports when action is completed.– Note: Every report must include the
complete status of all engines, even if only one was changed.
• Acknowledgement: Conn will acknowledge all reports with “Very well”
EXAMPLES
Order: “All engines ahead standard, indicate 115 revolutions for 16 knots.”
Reply: “All engines ahead standard, indicate 115 revolutions for 16 knots, aye.”
Report: “Ma’am, engine room answers all engines ahead standard, indicating 115 revolutions for 16 knots.”
EXAMPLES
(Continued from previous slide)Order: “Indicate 122 revolutions for 17
knots.”Reply: “Indicate 122 revolutions for 17
knots, aye.”Report: “Ma’am, engine room answers
all engines ahead standard, indicating 122 revolutions for 17 knots.”
EXAMPLES
Order: “Port engine ahead 1/3, starboard engine back 2/3.”
Reply: “Port engine ahead 1/3, starboard engine back 2/3, aye.”
Report: “Ma’am, engine room answers port engine ahead 1/3, starboard engine back 2/3.”
EXAMPLES
(Continued from previous slide)Order: “Starboard engine stop.”Reply: “Starboard engine stop, aye.”Report: “Ma’am, engine room
answers starboard engine stop, port engine ahead 1/3.”
EXAMPLES
Order: “All engines ahead 1/3, indicate pitch and turns for 5 knots.”
Reply: “All engines ahead 1/3, indicate pitch and turns for 5 knots, aye.”
Report: “Sir, engine room answers all engines ahead 1/3, indicating 075 turns and 34% pitch for 5 knots.”
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