The current always carries my sinker away

[onwind]

I have been trying bottom fishing in grand river maitland port for several weeks. but I always met this problem: the current there is so strong that it always brings my sinker away. if I release the line, it will be let out constantly, if I hold the line, it will finally be blown to very near the shore, but my plan is to anchor my bait at the bottom in the middle channel of the river. I have tried several solutions:
1. changed my egg sinker to no roll sinker, just move slower.
2. use heavier sinker up to 4 oz, it's still moving.
do you have any suggestion for this problem? should I up-size my sinker to 8oz? I am worrying how I can throw it far enough.