B&G Deckman - Manual (Page 54)

Navigation options
3.27
Deckman has the possibility of using tidal information from SHOM, the
French Hydrographic office. For this you require additional files and
release codes.
If you have the SHOM files, then it is possible that Deckman will have
to choose between this and its own database. This is done on the basis of
the area covered by the tidal chart with smaller areas preferred as they
are assumed to be more accurate.
One thing you need to be aware of if using the SHOM files is that
Deckman makes the selection described above regardless of whether
there are any high water times entered meaning that, if no HW times are
entered for the smallest area at a particular location, then no tidal
information will be seen for this area (it will always show 0 for both rate
and direction). You must therefore either ensure that HW times are fully
entered or you can remove the files – please see Tide files on page 12.7.
If neither of these sources of tidal data cover your patch then B&G can
create a personal database if you have the necessary information.
LKCS
The Local Knowledge Current Server covers particular areas, mainly in
North America.
Position
The Use Position option gives you a choice of the source of the yacht’s
present latitude and longitude which is used in all the navigational
calculations.
dead rk actually uses the estimated position, which is the
dead reckoning position adjusted for current.
GPS position fixer—usually GPS.
When you switch between Simulation mode and normal use, this will
automatically toggle between dead reckoning and GPS. The only time
you should have to change the setting here is if your GPS fails, in which
case you will want to switch to using Deckman in dead reckoning mode.