The ultimate reference for all of
Panama is the Bauhaus guide.
I dont like to encourage
piracy of such a great product, but there are digitized versions of his
charts out there.
Navionics is not bad for
Canal area and Pacific coast (pretty poor for San Blas though).
I use a combination of
Navionics & Bauhaus for kayaking/sailing in Golfo de Chiriqui (beautiful area).