Boats aren't moved by flowing water.

I don't think that boat is in flowing water in that picture.

It is.

I can't tell if its flowing unless there's a GIF.

Can't you just take my word for it? I wouldn't go through the trouble of making an account just to report a fake bug. Its flowing away from the camera

Sorry. I don't think I can take your word. Please provide a video or GIF showcasing the bug.

This design used to work, but it now moves way too slow, which is the bug I'm reporting. Thanks for the remedy though, I will let the water flow further.

Confirmed for 14w21b that the source water block does not affect the boat but I am not sure if this was earlier like this, tested it in 1.7.4 and was neither working there

Is this still a concern in the current Minecraft version? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases. If this has been done, we can reopen the issue.

Keep in mind that the "Resolved"-Status on this ticket just means "Answered", and that we are waiting for further information on whether this issue still exists or not. We will reopen it as soon as the requested information has been delivered.

Ticket resolved as incomplete, because no answer in a reasonable amount of time (1+ year), if it still happens, please update the ticket.

Fixed as of 1.11.2.