Yes. There are sightseeing boats which do river tours all year long.
how long wil it take to sail from RSA to Odessa
Trick question. You can't sail a steamship.
There is no set time it would take. Also, the time would greatly depend on the wind.
It would depend on what speed you were travelling at.
100 years
11 days
542 days
5 months
2 hours
90 days
it takes 5 hours