Description
Subtract nonnegative waterSpeed from nonnegative groundSpeed.
Marine speed, thrust, and propeller ratios depend on a declared reference frame and coherent units. A scalar term usually describes only one part of vessel performance.
Subtract nonnegative waterSpeed from nonnegative groundSpeed.
When to use this tool
Use Nautical Speed Over Water Ground Gap when you need one explicit marine performance ratio or residual.
How to use the tool and how it works
- Enter groundSpeed, waterSpeed. Use the units and conventions below.
- Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
- Read gap. Use the output convention below.
Subtract nonnegative waterSpeed from nonnegative groundSpeed.1
| Input field | Meaning and units | Accepted input |
|---|---|---|
| groundSpeed | Ground Speed | Required. Finite number; minimum 0. |
| waterSpeed | Water Speed | Required. Finite number; minimum 0. |
| Output field | Interpretation | Returned shape |
|---|---|---|
| gap | Signed difference under the stated subtraction order. | Required. Finite number. |
json
{
"input": {
"groundSpeed": 12,
"waterSpeed": 10
},
"output": {
"gap": 2
}
}Limitations and assumptions
- Use matching speed units; the scalar difference alone is not a current vector or navigational correction.
- 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 measured operating data and a vessel-specific propulsion model for performance predictions.
References
Similar or alternative tools
- Nautical Time Distance Residual
Multiply nonnegative speedKnots by elapsedHours for modelNauticalMiles.
- Wake Fraction Water Inflow Term
Divide nonnegative inflowSpeed by positive shipSpeed and subtract the quotient from one.