Furuno DS-60 Installation Manual page 50

APPENDIX 1 CALIBRATION
2. Calculation with DS-60
To measure the distance run between points A and B by DS-60, do the following:
1. Reset the distance run figure of DS-60 to zero by selecting [Reset] on the [Trip DIST] menu
at the moment the ship passes point A.
2. Run the ship from A to B at full speed, timing with a stopwatch.
3. Read the distance run (nm) and time taken to run (second) exactly at the moment the ship-
shape point B.
4. Run the ship from B to A at full speed rehearing to step 1 through step 3.
Where,
n1 (nm) = distance run from A to B measured by DS-60
n2 (nm) = distance run from B or A measured by DS-60
Therefore, the average run from A to B measured by DS-60
Therefore, the average ship speeds of run 1 and run 2 are calculated as follows.
Slog1 (kn) = n1/t1 X 3600
Slog2 (kn) = n2/t1 X3600
The average ship speed of round trip is Slog (kn) = (Slog1 + Slog2)/2 ...(6)
3. Speed error
From (5) and (6),
Error = (Sw - Slog)/Slog X 100 (%)... (7)
This error can be corrected at [OFFSET DATA] on the [System] menu as follows:
1. Press the MENU/ESC key.
2. Select [System] and press the ENT key.
3. Select [OFFSET DATA] and press the ENT key.
4. Select [SOG CALIBRATION], [STW CALIBRATION] and press the ENT key.
5. Enter the value of error.
Repeat the above procedure several times to satisfy the speed accuracy specification.
AP-2