Bowerthane,
You appear to confirm that the Bosworth/Toller Supplement rejects the idea of 'craeft' representing a "vessel".
Delete 'IV. a CRAFT, any kind of ship; navis qualiscunque';
and you further state that such use did not apply until the modern English language era (1670s); but then your final conclusion is that Phyllis could therefore use this variant of the word in an OE setting.
I'm struggling to follow the logic of the argument, or have I missed something.
Admittedly, the B/T Supplement does add a new sub-section 4; i.e.
"IV. a machine, instrument, engine",
but I have some doubts concerning the examples given there, as they are difficult to assess without analysing the overall context from which they come.
Brian