Has anyone tried this in a similar situation (i.e., specifically where the
GPS does not correspond to the latest charts)? Is this a good idea in the
first place?

s/v Kerry Deare

Experience with screwy charts......... to be brief: all of them are
suspect.

should you keep a LORAN? **** no. If youre so convinced with its
effacy I thnk yould best get an ADF to comliment your nav suite.

Use standard terrestial/near coast dead wreckoning stratiges plus gps.

bob