SSB and NAVTEX receiver antenna setup?

[Capt.Alex]

I have the typical SSB setup, insulated backstay connected to antenna tuner. I got my hands on a Furuno NAVTEX reciever and would like to install it without adding the optional active antenna coupler with whip. The manual says you can use an insulated backstay, but not if you also have an SSB. Since the NAVTEX is a receive only unit, is it necessary to use an insulated backstay? Is there a good reason I can't connect the antenna lead to one of my chain plates, using a shroud as a long wire antenna? Anyone here use a NAVTEX and SSB?