Can I edit my .dat data file to add some explanatory notes to the header?

Seasoft V2's Seasave (older software, replaced with Seasave V7 in 2007) created a .dat file from data acquired from the SBE 11plus V2 Deck Unit  / SBE 9plus CTD. This also applies to earlier versions of the Deck Unit and CTD.

Some text editing programs modify the file in ways that are not visible to the user (such as adding or removing carriage returns and line feeds), but that corrupt the format and prevent further processing by Seasoft. Therefore, we strongly recommend that you first convert the data to a .cnv file (using SBE Data Processing's Data Conversion module), and then use other SBE Data Processing modules to edit the .cnv file as desired.

Sea-Bird is not aware of a technique for editing a .dat file that will not corrupt it. 
Sea-Bird distributes a utility program, Fixdat, that may repair a corrupted .dat file. Fixdat.exe is installed with, and located in the same directory as, SBE Data Processing.

Note: Seasave V7 creates a .hex file instead of a .dat file from data acquired from the SBE 11plus V2 Deck Unit / SBE 9plus CTD. See the FAQ on editing a .hex file.