I can vouch for Caney Creek, BlueSprings and Euchee being open. I know one of the marinas on the Spring City side recently closed down and assets were auctioned.
And BTW, if you are transiting Watts Bar and see Long Island Marina on the chart it aint there. Hasn't been for some time and it's still on some charts. Bad thing is that it was the farthest marina up river. A lot of people get into a fuel problem in that last 40 miles before Ft. Loudon Lock.
1981 32' Sedan Fly Bridge
440 ci 330hp (2)
7.5 kw Kohler
"International Harbor Marina"
Friendsville TN, TN River