Nautical Reference Tables
Distance Conversions
| From | To | Multiply By |
|---|---|---|
| Nautical Miles | Statute Miles | 1.15078 |
| Nautical Miles | Kilometers | 1.852 |
| Nautical Miles | Meters | 1852 |
| Statute Miles | Nautical Miles | 0.86898 |
| Kilometers | Nautical Miles | 0.53996 |
| Fathoms | Feet | 6 |
| Fathoms | Meters | 1.8288 |
| Feet | Meters | 0.3048 |
| Meters | Feet | 3.28084 |
Speed Conversions
| From | To | Multiply By |
|---|---|---|
| Knots | MPH | 1.15078 |
| Knots | KPH | 1.852 |
| Knots | m/s | 0.51444 |
| MPH | Knots | 0.86898 |
| KPH | Knots | 0.53996 |
| m/s | Knots | 1.94384 |
1 knot = 1 nautical mile per hour
Volume & Weight
| Item | Value |
|---|---|
| Fresh Water | 8.34 lb/gal |
| Salt Water | 8.55 lb/gal |
| Diesel Fuel | 7.1 lb/gal |
| Gasoline | 6.1 lb/gal |
| Salt Water Density | 64 lb/ft³ |
| Fresh Water Density | 62.4 lb/ft³ |
| 1 Long Ton | 2,240 lbs |
| 1 Metric Ton | 2,205 lbs |
Temperature
| °F | °C | Notes |
|---|---|---|
| 32 | 0 | Freezing point |
| 50 | 10 | Cool |
| 68 | 20 | Room temp |
| 77 | 25 | Warm |
| 86 | 30 | Hot |
| 212 | 100 | Boiling point |
°C = (°F - 32) × 5/9 | °F = °C × 9/5 + 32
Speed & Distance
Hull Speed
Speed (knots) = 1.34 × √LWL (feet)
Speed/Length Ratio
S/L = Speed (knots) ÷ √LWL (feet)
Distance = Speed × Time
D (NM) = S (knots) × T (hours)
60 D Street Rule
Distance off = (Angle × 60) ÷ Boat lengths
Anchoring
Scope Calculation
Rode = (Depth + Freeboard) × Scope Ratio
Recommended Scope
5:1 calm | 7:1 normal | 10:1 storm
Swing Radius
Radius = Rode Length + Boat Length
Displacement
Displacement
Disp (lbs) = LWL × Beam × Draft × Cb × Density
D/L Ratio
D/L = Disp (lbs) ÷ (0.01 × LWL)³
Block Coefficient (Cb)
Racing: 0.35-0.40 | Cruising: 0.45-0.55
Navigation
1 Degree of Latitude
= 60 nautical miles
1 Minute of Latitude
= 1 nautical mile
Radar Horizon
Range (NM) = 1.22 × √Height (feet)
International Signal Flags
| Flag | Letter | Meaning (Single Flag) |
|---|---|---|
| ■ | A (Alfa) | Diver down; keep clear |
| ■ | B (Bravo) | Dangerous cargo |
| ■ | C (Charlie) | Yes / Affirmative |
| ■ | D (Delta) | Keep clear; maneuvering with difficulty |
| ■ | E (Echo) | Altering course to starboard |
| □ | F (Foxtrot) | Disabled; communicate with me |
| ■ | G (Golf) | I require a pilot |
| ■ | H (Hotel) | Pilot on board |
| ■ | Q (Quebec) | Request pratique (health clearance) |
| ■ | N (November) | No / Negative |
| ■ | O (Oscar) | Man overboard |
Vessel Parts
| Bow | Front of the boat |
| Stern | Back of the boat |
| Port | Left side (facing forward) |
| Starboard | Right side (facing forward) |
| Beam | Width at widest point |
| Draft | Depth below waterline |
| Freeboard | Height above waterline |
| LOA | Length Overall |
| LWL | Length at Waterline |
| Keel | Bottom centerline structure |
| Helm | Steering station |
| Transom | Flat stern surface |
Navigation Terms
| Heading | Direction boat is pointing |
| Bearing | Direction to an object |
| Course | Intended direction of travel |
| Track | Actual path over ground |
| SOG | Speed Over Ground |
| COG | Course Over Ground |
| VMG | Velocity Made Good |
| ETA | Estimated Time of Arrival |
| ETD | Estimated Time of Departure |
| Waypoint | Navigation reference point |