Maybe a more 'modern' usage but sometimes to 'fish' means to use something to work a wire, rope, halyard, etc. through a fitting or a mast.
As 'we used a long rod to fish the mast light wire up through the mast so it could be connected.'
The boat I race on has lines (halyards, sheets, etc. running through a 'tunnel' on the deck. We have to fish the lines through the tunnel every year as we put the mast back on after the winter.