Description
Compare observed sailing speed with a supplied polar reference speed.
Nautical quantities require explicit north, datum, sign, station and unit conventions. A wrapped bearing error has a chosen opposite-direction endpoint, while a circular sector has its own start and end policy. Supplied polar speeds, tank factors and tide labels are references rather than verified navigation or vessel conditions.
Compare observed sailing speed with a supplied polar reference speed.
When to use this tool
Use Sailing Polar Single Speed Ratio when you already have observedSpeed, suppliedPolarSpeed and need to compare observed sailing speed with a supplied polar reference speed.
How to use the tool and how it works
- Enter observedSpeed, suppliedPolarSpeed. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read speedRatio, speedDifference. Use the output convention below.
Require observedSpeed>=0 and suppliedPolarSpeed>0; return observed/reference and observed-reference.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| observedSpeed | Observed Speed | Required. Finite number; minimum 0. |
| suppliedPolarSpeed | Supplied Polar Speed | Required. Finite number; strictly above 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| speedRatio | Speed Ratio | Required. Finite number. |
| speedDifference | Speed Difference | Required. Finite number. |
{
"input": {
"observedSpeed": 6,
"suppliedPolarSpeed": 8
},
"output": {
"speedRatio": 0.75,
"speedDifference": -2
}
}Limitations and assumptions
- Use matching speed units and conditions; the ratio may exceed one and no polar, route, performance cause or safe maneuver is determined.
- Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.
- Numeric calculations use binary floating point unless exact decimal-integer arithmetic is explicitly stated. No hidden measurement tolerance or decimal rounding is added; nonfinite or out-of-contract results are rejected. Numeric signed-zero results are exported as zero.
Alternative or Complementary methods
Use verified charts, observations, vessel documentation and the complete relevant geometric or hydrostatic model for a navigational question. Preserve the local bearing/datum convention and treat scalar factors or sector checks as limited inputs rather than operational decisions.
References
Similar or alternative tools
- Nautical Log Calibration Distance Ratio
Calculate a distance calibration factor as reference per indicated distance.
- Tank Sounding Volume Factor Apply
Apply a supplied correction multiplier to a tank-table volume.