ASW Definitions Flashcards
What is a DATUM?
- Last known position of a submarine or suspected submarine once contact has been lost.
- Label and maintain 4 fig track number (e.g. once lost and comes back).
Expressed as;
- range/bearing from unit
- range/bearing from ref point
- grid
- lat and long
What is a DOGBOX?
- Area homing torpedo is active
- Established by unit releasing torpedo
- Lasts for 8 mins
- Radius of 3000 yards
What is the Furthest On Circles (FOC)?
- Visual representation of how far the submarine travelled from datum from their course and speed.
- Helps command gauge proximity of submarine, assessing danger to the force.
What is the Torpedo Danger Zone (TDZ)?
Area submarine has to enter to be within Maximum Effective Torpedo Firing Range (METFR).
Limited Lines of Submerged Approach (LLSUA)
- Mathematically calculated limits related to the force which the attacking submarine, knowing the course and speed of force, must be located to reach TDZ in direct line.
- Used to find out if the submarine is a threat.
What is The Grain?
- The submarine does not have to move to fire upon the force
- OTC alters MLA so DATUM is outside.
What are the Torpedo Counter Measures (TCM’s)
- Changes course and speed
- Deploy counter measures
- Counter torpedo fire
- Switch on/off noise makers
Name and define the types of ASW Action?
- Close ASW Action
1 or more ASW units aim to engage submarine within 8,000 yards - Stand-off ASW Actions
1 or more ASW units aim to engage submarine outside 8,000 yards
best to do stand-off so ships are outside TDA
conduct attack = brother
assist attack = sister
What are the different Contact Classifications?
NONSUB (Non-Submarine Contact)
- Has characteristics that exclude the possibility of it being a submarine
POSSUB (Possible Submarine Contact)
- Sufficient evidence suggests likely presence of a submarine, insufficient evidence of higher classification.
Confidence levels:
- Low confidence = cannot be nonsub requires further investigation, grade 1 and 2. - High confidence = is firmly believed to be a submarine, grade 3 and 4.
PROBSUB (Probable Submarine Contact)
- Strong evidence of being a submarine (held on more than 1 sensor)
CERTSUB (Certain Submarine Contact)
- Sighted and positively identified as a submarine.
What are the 4 Datum Approach Methods?
Direct (reduce submarines freedom of movement, forced in 1 direction)
- When a unit is in contact
- DATUM within 6nm of main body/TDZ
Offset (reduce submarines freedom of movement, forced in 1 direction)
- When no unit is in contact
- DATUM more than 6nm from main body/within 30 degrees of MLA
Intercept (intercept the submarine on most dangerous/likely course)
- When no unit is in contact
- DATUM more than 6nm from main body/ greater than 30 degrees of MLA
Mixed (give submarine max food for thought)
- When ship is dispatched on intercept approach and other ship proceeds on an offset approach.
What are the two Search and Attack Plans?
- Search/Support plans are known as “Plans Black”
2. Attack Plans are known as “Plans Red”
What is involved in Plan Cordon?
- Most commonly used search and attack plans
- Plan black or red
- Sector zero (3,000 yards)
- Ship remains outside sector 0 unless cleared to enter
- 8 sectors of 45 degrees, 1-8, no outer limit
- Plan orientated on North
- Ships cannot manoeuvre within 500 yards of sector boundaries in order to prevent mutual interference
What are the 3 methods of Gridlocking?
- Radar Gridlock = aircraft held on radar
- Reverse Radar Gridlock = aircraft holds the ship on radar
- Visual on Top Gridlock = When neither aircraft nor ship holds the other on radar but aircraft is visual on ship
What do Dippers do on ASW SOP?
- Chirp Code when transiting
- Chirp Single when marking a dip
- Chirp Code when they gain contact
- If contact classified as POSSUB Low 2 or higher then nearest other dipper, not on positive control, joins to assist in prosecution.
What is the Torpedo Danger Area?
- An area extending beyond a submarine contact, DATUM, FOC by same distance as threat submarines METFR.
- Used by surface forces to maintain safe stand-off distances
- 8,000 yards gap around ship
- 10,000 yards gap around the force
