About difference between: "Plattedeutsh" and "Hamborger Platt"

Here two native Germans who asked my question about the difference between the two varaieties of German:

Source One:
1. Plattdeutsch ( Low German) is a germanic language variety spoken especially in northern Germany, depending in the Region you can find plenty of under categories such as ostfriesisch, Oldenburger platt, Hamburger platt and many more.
So the answer to your question is: No it's Not the Same, Hamburger Platt is an under category of Plattdeutsch
2. Following Link will direct you to an excellent Video to learn the Song, as it's Not sung by are couir. https://youtu.be/CzJNM2QF7qU

Source Two:
"Plattdeutsch ist eine eigene Sprache mit eigener Grammatik! Haben es noch in der Schule gelernt! Die Hamburger sprechen einen Dialekt! Und auch das Friesische ist eine völlig eigenständige Sprache die aber auch gar nicht mit dem Platt und dem Hamburgischen Dialekt zu tun hat!".
English Translation:
"Low German is its own language with its own grammar! Learned it in school! The people of Hamburg speak a dialect! And Frisian is also a completely independent language that has nothing to do with the Platt and the Hamburg dialect!".

That is tented me to opinion to that dialect are different, or at least German natives see this difference clearly. Of course to find what is a difference in those dialects is out of the scope of my research, but I know for sure, I need to find native German, who speak in "Hamborger Platt", to be close as possible to recreate further, German shanties and forebitters from Stan Hugill's book.