I guess it depends on your interpretation of the song, but I'm not certain that it's necessary for the plot of the song to specify that it is a ferry as opposed to any other kind of voyage that you are paying for; the key, in my mind, is the idea of paying the person responsible for your safe passage before said goal has been achieved, for fear that they will not deliver on their part of the bargain.
//loghaD
bom: don't pay the ferrymanQoQ ghom: twinball
"don't pay the ferryman, don't even fix a price, don't pay the ferryman until he gets you to the other side"
< bIQ Duj pIn'a' yIDIlQo', DIlmeH Huch poQbogh yIlajQo', bIQ Duj pIn'a' yIDIlQo', SoHvaD Dop Dop qengpu'pa' >
bomvam vImuSHa'.
I wonder if bIQ lupwI' pIn'a' might be better for ferryman. Transporting something or someone is integral to the meaning of ferry.
Instead of SoHvaD Dop Dop qengpu'pa', how about DuchIqmoHchu'pu'pa' before he has caused you to cross completely?
-- SuStel http://trimboli.name