Expedition Navigation Software 
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- Expert
Offline - Registered: 12/20/2015
- Posts: 84
Expedition Calculations & Calibrations
Hello,
1) When I select "Leeway from heel and bsp" in Exp. Calculations. Which K-factor is taken?
Under "Exp Calibration" I can enter a number for Leeway in a 1x1 table. But the description below the table says "TWA across table, TWS down table" which is a bit misleading.
Is this where the K factor has to be entered?
2) If I understand correctly under Exp Calibration I can calibrate for example my BSP for heel and speed correction if my instrument system is not capable to do so.
So I filled out the table there and set it active.
I tried this in a simulation where I have Deckman running in simulation mode and DfW2Exp sending the numbers to Expedition - the closest I can get to simulate an instrument connection without being on board. I expected the Expedition BSP to differ from the DfW2Exp input BSP by the numbers in the table, but it doesn't. Is this a pure simulator issue or am I doing something essentially wrong?
- Nick
- Moderator
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- Registered: 9/16/2015
- Posts: 2,740
Re: Expedition Calculations & Calibrations
Normally you have just the single k value, but it is possible to have a table.
It may not affect the simulator, but I don't 100% recall
- radaroom
- Expert
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- Registered: 1/02/2020
- Posts: 29
Re: Expedition Calculations & Calibrations
Update on Leeway
The Default value is 32.
I have VPP data from the boat designer for heel, target BSP and predicted leeway.
Should this table be Leeway by TWS Vs TWA or is it 'k' the coefficient (which would have to be calculated from leeway, heel and BSP as per the formula in the manual)?
If the default is correct then how does it affect Course?
Some advice on this please.
- Nick
- Moderator
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- Registered: 9/16/2015
- Posts: 2,740
Re: Expedition Calculations & Calibrations
32 is a very high k value, about 3x anything I have ever had to use.
I just checked and the default value in Exp is 13, which is more normal.
Of course, you are generally best to just use the instrument values for leeway if available.
- radaroom
- Expert
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- Registered: 1/02/2020
- Posts: 29
Re: Expedition Calculations & Calibrations
Would anyone be able to supply a heel and leeway table (a dummy one would be fine) so I can get the format right (positive and negative).
Many thanks!
- Nick
- Moderator
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- Registered: 9/16/2015
- Posts: 2,740
Re: Expedition Calculations & Calibrations
Heel/roll and leeway are in the conventional sense.
A roll to starboard is positive, ie on port. Similarly leeway is positive on port as it is a clockwise rotation.
See the Exp help on calculations.