Way north bass guy

I have a few quiet spots. For many years, I’ve spent a fair bit of time out on Georgian Bay. There’s quite a bit of boat traffic in the summers on the main channels and close to town, but once you get about 1/2 hour away from town, there’s literally hundreds of back bays and offshore shoals where you’ll never see another human all day, no matter what time of year it is. 
My newest quiet spot, also my new favourite, is the river that runs right through my property we bought two years ago. I have a section about 500yds long that goes directly through my land, no boats can access it other than a canoe or kayak from the lake it runs out of, and I doubt there was even a single one through here the last couple years other than me. I can walk across my field after work in the summer, and sit there on the shore or float the canoe and catch a bunch of smallmouth and largemouth on topwaters, some sort of Texas rig or with the fly rod. All you hear is the frogs and birds. It is truly heaven, right behind my house!

Oh boy, that’s exactly the kind of chimney workmanship that pays for my boat every year ? ( along with all my other bills).
 
All it takes is a pinhole for the water to get in and do a lot of damage. In the case of a brick chimney similar to yours, it usually boils down to one of ( or possibly both of ) two things. 
 
Firstly, like everyone else mentioned, double and triple check all around the flashing. Any opening or crack can be an entrance for water, especially if the wind forces it in. That flashing doesn’t look too terrible, but like everyone else said, silicone the bejesus out of it wherever there’s a joint that looks like rain can get in, use clear silicone and it won’t be noticeable from the ground.
 
The main thing I see wrong here though, is the horrible “cap” on the top of the bricks.
I’ve lost count years ago of the number of masonry chimneys I’ve fixed that looked exactly like yours, the bricklayers just finish the top row off and pile a bit of mortar on there to “shed” the water. Problem is that if there’s any freezing at all, it soon opens up a few cracks, that then only speeds up the progress of decay. Also, there is no overhang at all on your chimney to stop all the water from running down the sides of the chimney and ruining the brick faces. 
 
Keep the water out of the top, and the rest of the chimney will be around for decades, even up here in the North where it’s very, very well below freezing for months at a time. 
 
About the only  way to fix this properly is to pour a reinforced concrete cap on top of the chimney. 
 
In your case, from the pics I see it looks like the main brickwork is still in decent shape, so you shouldn’t need to remove anything. 
Easiest way to do it is to build a custom form out of plywood  for the bottom edges and 2x4s for the sides. You want to make it so the inside of the form just barely sits on the top row, and the outside of the form is approx 5” wider all around than the chimney, that way when you remove it, the concrete cap should have about a 3-3.5” overhang. Mix up your concrete fairly wet, fill up the form and slope it towards the flue, and don’t forget to run a few rows of 1/2” rebar throughout the concrete for extra strength. 
 
Leave it for a couple days, then remove the forms, and take a grinder with a masonry blade and grind a drip edge all around the bottom of the overhang. This will create a spot for the water to catch and drip off the cap, rather than run down the side of the bricks. 
 
A masonry waterproofing brushed on the concrete will also help, but don’t seal the bricks. You want them to “breathe”, if they can’t then any water trapped inside will make the bricks faces blow out if it freezes. 
 
If it’s warm enough that you aren’t using the chimney right now, but don’t want to tackle this job right away, the best way to stop leaking temporarily is to wrap the whole thing with a tarp. 
 
Also, check the roof in the area around the chimney, even an exposed roofing nail or broken shingle 10’ away can be a spot for the water to enter, then travel along the roof underside till it hits the chimney and runs down to your ceiling. 
 
Here’s a couple pics from online just to give you an idea of what it should look like. 

I regularly store about 18 or so rods in the boat at all times with fluoro or mono on them of various lb tests. Lure goes on the hanger near the reel and the line is just tightened up enough to not get tangled with the others ( they’re all in rod socks as well), and they will get a slight kink right at the rod tip, but I’ve never once had an issue with it breaking at that point. I’d say as long as your not cranking it down super tight, it should be just fine. Hook a couple fat ones next time out and it’ll stretch out perfectly ?.