-- see discussion below --
First of all, "estrarre il perno dx del tratto di mast superiore" seems to be saying "Remove the right-hand pin of the upper mast segment." Unfortunately, this sentence contains several ambiguities: "del" could also mean "from," as in "remove the right-hand pin from the upper mast segment." ( "Mast" itself is a borrowing from English; in Italian you'd expect the proper term "alberetto.") "Right-hand" could also be "right-side," or "starboard." As for "falchetto," it's unlikely to be a jib, which is "fiocco." (It's also customary to take down the sails before doing work on masts or standing rigging.) As for the phrase "completo di falchetto," I suspect that in this context "falchetto" is a coined term or highly specific piece of nautical jargon, possibly referring to a fitting located on, or at the top of, the mast (a directional wind indicator, perhaps?). The sources I've consulted give "falchetto" as "falconet" or "hobby" (where "falconet" refers to Renaissance artillery, specifically a small cannon, or to a small European bird in the falcon family, whose Asian counterpart is the "hobby"). "Falchetta," ending with an "a" rather than an "o", is the Italian word for the gunwale (gunnel, sometimes also known as the "washboard"), which is the uppermost edge of the side of a boat - the part into which the oarlocks are set, in the case of a rowboat, or the part over which people sometimes trip and fall into the water. I can't imagine a gunwale having much to do with the upper part of a mast, although if you're stepping a mast (that is, inserting it vertically into place, as one does with small sailboats), you'd certainly want to avoid damaging the lower part of the mast, or the side of your boat, by any accidental contact between them. -- In summary, then, your text seems to refer to the removal of a pin or of a segment of mast, along with a small element (the "falchetto") which apparently belongs to the mast. -- I'm sorry I couldn't be more helpful, but perhaps these observations may save you some research time or suggest a useful different approach to the problem.
Old-fashioned paper dictionaries (Marolli, Sansoni, Harrap-Zanichelli), plus my own experience
as a long-time day-sailor and USSA-accredited sailing instructor.
Local time: 05:25
Native speaker of: English
PRO pts in pair: 504