I tried to knock out the entire Fishing questline from the suggested tab, but honestly it feels impossible. Today I wasted two hours just trying to figure out how to harpoon fish. After messing around in the ocean, Googling, and watching YouTube videos, I still couldn’t find any clear explanation of how harpooning actually works. Why is it so vague? Also, why BDO streamers are so bad at explaining stuff? Anyways, please either rework harpoon fishing so it makes sense, or just remove it from the game altogether. Thanks.

You have to be on a fishing boat for starters, either the one labled fishing boat or the swift boat that can not be repaired, you can not harpoon from a large ship.  

As @Werbs mentioned, there are some weird limitations to this part of the game. But it is surely one more part of the Life-skills which truly need some reworking, and the way they changed the fishing into a button (at the top of the screen) to push, before you can either move around normally, or start fishing, was an atrociously bad decision. Making the game more confusing and less intuitive, is certainly not great.

YES. The current system is both incoherent and not fun. 

Not fun, because boats that small do NOT belong in Nineshark-infested parts of Margoria, and because the minigame is extremely repetitive, takes too long, and doesn't reward player skill OR fishing skill increases much at all.

Incoherent, because it seems like whoever designed it totally confused spear fishing with harpooning. NPCs are shown "harpooning" from shore with spears. The minigame has us repeatedly "stabbing" at the fish in the water. And somehow, we AREN'T using harpoons when we hunt the Humpback (which should really be about the size of a Hekaru, btw) and Blue Whale, we're using matchlocks! 

Real harpoons have a big backwards barb at the end and a rope tied to them, and are either thown, or fired from spearguns or ship-mounted harpoon cannons. They are only used for really big targets, from at least as big as a person on up to blue whales, and historically are THE whaling weapon of choice. If you hit, the barb stays in while the fish or whale tries to pull away, wriggle off, or simply flee - pulling the boat with it if it's strong enough! - and eventually the big fish tire enough to be hauled on board by the rope, or the whales too big to haul in that way die of blood loss.

Blue Whale hunts have become sorely underattended, making the Hunting Leap quest chain extremely difficult... so as long as we're looking at harpooning, it makes good sense to rework whaling along with it. So here's my suggestion for how Harpoon Fishing AND Whale Hunting should be revised to be more fun, and make sense!

SPEAR FISHING:
- requires being on a small boat, as now, OR on shore (as depicted for NPCs)
- uses the existing harpoon items, just renamed and given a spear-fishing animation (like the NPCs) instead of a crossbow-like one.
- targets only moderately sized fish, from about a foot (30cm) to a yard (meter) long.
- rework the existing minigame so the fish doesn't automatically move from your stab, but it must actually be solidly hit - ONCE. Grazing hits slow it down.

HARPOONING:
- requires being on a large ship
- requires new equipment that uses the existing Thick Harpoon as a manufacturing component - Blue tier Speargun, or Yellow tier Harpoon Cannon (presumably Marni-designed) 
- targets only the largest fish (such as marlins), sharks, and whales, including Blue Whales and Humpbacks.
- Firing the harpoon is like firing a matchlock (or sniper rifle?), and uses the average of your Hunting + Fishing skill. Assuming you hit, you then have a timer to attach the rope to the ship's mast, or the target and 1 durability of your harpooning weapon are both lost. For most targets, that's all you need to do - they thrash around for a bit before dying, or escaping if your skill level isn't high enough to guarantee success, but then an animation of pulling the fish in is played.
- however, the Blue Whale is big enough to pull your ship for some time before it dies. And the ship captain(s) have to handing steering around obstacles behind the whale, as if it's dragged into them, the ship takes damage! (The ship patching items should be reviewed as part of this... right now, the workshop version is no better than the cheaper one it's made from.) More harpoons and more/bigger boats = dies faster and drags ships slower, but it should still be doable by a team of one harpoonist and one captain, in a reasonable amount of time,
- The first Blue Whale quest in the Hunting Leap chain should be revised to "hunt any whale or fish with a harpoon", and the second should be what the first is now (hunt and loot a Blue Whale).

Needs a major revamp or removal.

I totally gave up on harpooning. The constant background oscillations are seriously sick making. Probably because there is little else to focus on.

Literal worst life skill in the game. PLEASE remove or revamp before setting any more harpoon-exlcusive weekly fishing tournament targets. This week's Black Spotted Dolphin is so painful and just reminds me how awful parts of this game can be.

Just make the harpoon a Corsair underwater weapon