- Bank Cushion Effect
- Shallow Water Effect
- Passing Ship Effect
Line numbering Acronym
- Bow, After/Fwd, After/Fwd, Stern
- Tug with omni-directional propulsion units mounted under the forward part of the hull.
- Most have a skeg under their sterns.
Tug with omni-directional propulsion units mounted aft.
the end of the boat that is tethered to the ship will be termed the working end.
The amount of line force that can be applied to the tug’s working line at zero speed.
The amount of force applied to the tug’s working line at various speeds.
wedge of water between ship and bank builds up forcing bow out sharply
decrease of water level near quarter due to suction of screw to bank => draws stern closer.
where the direction of flow is not restricted by any barriers, the tidal current is rotary; that is, it flows continuously, with the direction changing through all points
Reversing Tidal Current
in rivers or straits, or where the direction of flow is more or less restricted to certain channels […] that is, it flows alternately in approximately opposite directions with an instant or short period of little or no current, called slack water, at each reversal of the current.
when the tides at the two ends of a strait, such as the East River, New York, are seldom in phase or equal in range, and the current is generated largely by the continuously changing difference in height of water at the two ends.
is the movement of the current toward shore or upstream.
is the movement away from shore or downstream.
one close to shore and often classified as a costal current that flows roughly parallel to a coast outside the surf zone
that is parallel to a shore inside the surf zone generated by waves striking the beach at an angle
Charted clearance height for bridges is usually based _________________
on the average of mean higher high water (MHHW).
Charted depths on charts are usually based on ___________
the average of mean lower low water (MLLW)
The NAVDORM states that the only electronic tide/current programs the CO may authorize are:
- NOAA tides and currents (for U.S. waters)
- Admiralty Total Tide (all other areas)
- Tide Tables
Rock vs Island
- Rock can only claim a territorial sea
- Island can claim shelf, EEZ, cont. zone as well
Can nations close territorial seas?
- Yes, temporarily
- Except for international straits
- Max 24nm from baseline
- Coastal state authorized exercise control necessary to enforce and / or punish violations of:
- Customs laws
- Fiscal laws
- Immigration laws
- Sanitary laws
Exclusive Economic Zone
- Max 200 nm
- Sovereignty over resources
- Continuous and Expeditious traversing by ships solely for passage
- Stopping and Anchoring
- Incidental to Normal Navigation
- Rendering Assistance
Transit Passage Rights
- Unimpeded passage
- Continuous and expeditious
- “Normal mode” of transit
- Surface, air, and / or subsurface
- Same as Transit Passage
- Must remain within 25nm of centerline
Large vs Small Charts
- Sailing = Small (1:600k)
- Harbor = Large (1:50k)
- Sailing -> General -> Coastal -> Harbor
- Chart size from smallest to largest
Sounding datum in US
- A position determined without reference to any former position
- The common intersection of lines of positions (LOPs) obtained from simultaneous observations
- Composite Fix
- or Electronic Fix
Estimated Position symbol
Sun's bearing @ noon (northern hemisphere)
- Bearing is always 000 in southern hemisphere
6 rules of DR
- 1. Every hour on the hour
- 2. Every crs change
- 3. Every spd change
- 4. Every fix/running fix
- 5. After plotting a single LOP
- 6. DR out 2x fix intervals/ label with crs/speed/time
The period of incomplete darkness when the upper limb of the sun is below the visible horizon, and the center of the sun is not more than 6° below the celestial horizon.
The time of incomplete darkness which begins (morning) or ends (evening) when the center of the sun is 12° below the celestial horizon. The times of nautical twilight are tabulated in the Nautical Almanac; at the times given the horizon is generally not visible and it is too dark for marine sextant observations.
The time at which the sun crosses the observers upper meridian
an accurate means of determining Gyro Error by comparing what a celestial body’s compass bearing WAS with what it should have been if there had been no error.
Neumonic for compass/gyro error
Why is meridian transit important?
Helps us find latitutde
- The angular distance from the celestial equator
- measured north or south
angular measurement measured West through 360° from Greenwich
angular measurement measured west through 360 from local
Error of commission
things you did that you shouldn't have
cyclone vs anticyclone
- cyclone has terrible weather
- anticyclone has good weather, maybe some fog
boundary between one air mass and another
- violent thunderstorm initially
- followed by pressure increasing and skies clearing
Anything with "cirro" in it
Anything with "alto" in it
has two high tides and two low tides in a tidal day.
has one high tide and one low tide in a tidal day.
has a large inequality between the high and low tides of each tidal day.
- right-half (northern hemisphere)
- left-half (southern hemisphere)
- "back to your breeze" is for escaping
LCS-2 Displacement & Draft
- 3071 tons displacement
- 19.7 ft draft
LCS-2 Tactical diameter / Final diameter
- 2740 yds tactical
- 2690 yds final
LCS-2 # Shafts
(They want me to say N/A)
4 steerable waterjets
LCS-2 height of eye
LCS-2 Max height above waterline
Mine Immediate Actions
- Zebra maindeck and below
- non-essential personnel topside
- don't change degaussing
- consider prairie/masker
Aircraft in water immediate actions
- Make best speed towards it
- SAR plot
- man boat deck
- muster medical personnel
- add extra lookouts
who should brief casualties IAW NAVDORM?
Cross the T vs Parallel
- Cross the T for bad weather
- Parallel for fair weather
- <2 nm
- 3 min fixes or better
- FOM 2 or better
- 50 yds
- 2-10 nm
- 3-10 min fixes
- FOM 4 or better
- 100 yds
- 10-30 nm
- 15-30 min fixes
- FOM 6 or better
- 500 yds
- >30 nm
- 30 min fixes
- FOM 7 or better
- 1500 yds
Buoy vs Beacon
- Beacon has higher installation cost
- Buoy has higher maintenance cost
Flashing Red or Green light
Lateral buoy/marker at night
- In IALA B, preferred channel is the top color
- i.e. red top buoy means "go to port"
After Bow Spring Line
- Line 2
- Prevents Fwd Motion
- (Hold you back)
- True Bearing + 180 - Target course
- If answer is negative add 360
- If answer is greater than 360, subtract 360