I'll have to reread "Life on the Mississippi" and see if there are any more clues about "syphons" but I think you've about wrapped it up.
Here's a river version of "Roll the Woodpile Down" that appeared in another Mudcat thread which I think belongs here in full:
HOLD THE WOODPILE DOWN
Saw my love the other night Hold the woodpile down Everything wrong, just a-nothing was right Hold the woodpile down She can make me lovely, can make me glad Hold the woodpile down I kissed her, till here come her dad Hold the woodpile down
But I was travellin', travellin' As long as the world goes around Oh the black gals shine on the Georgia line Oh hold the woodpile down
Come to town the other night Hold the woodpile down Heard a little noise and I see'd a little fight Hold the woodpile down Police watchin' and a-runnin' all around Hold the woodpile down Glory, white lightning done come to town Hold the woodpile down But he was travellin', travellin' As long as the world goes around Oh the black gals shine on the Georgia line Oh hold the woodpile down Boat keeper swallowed a nickel one day Hold the woodpile down Run him most crazy, I must say Hold the woodpile down Oh listen now and I'll tell you what it's about Hold the woodpile down He's a nickle in and and a nickle out Hold the woodpile down But he was travellin', travellin' As long as the world goes around Oh the black gals shine on the Georgia line Oh hold the woodpile down Down to the packing house, stoled a ham Hold the woodpile down Folks don't know how bad I am Hold the woodpile down Carried it home and I laid it on the shelf Hold the woodpile down Just so bad, I'm scared of myself Hold the woodpile down But I was travellin', travellin' As long as the world goes around Oh the black gal shine on the Georgia line Oh hold the woodpile down Love my wife, I love my baby Hold the woodpile down Love them biscuits a-broken in gravy Hold the woodpile down Carry my dice for to throw my passes Hold the woodpile down Love them flapjacks floating in molasses Hold the woodpile down But I was travellin', travellin' As long as the world goes around Oh the black gals shine on the Georgia line Oh hold the woodpile down.
Source: Uncle Dave Macon 'Hold the Woodpile Down' Recorded 7 May 1927. Reissued on Uncle Dave Macon 'Go Long Mule' County CO-CD-3505.