I just discovered a super awesome way to dispatch sirens and ekhidna that surround all of the smugglers caches in the sea or any others that might attack you while you are commanding a boat, one that I have not heard anyone mention anywhere to date, nor seen anyone perform in any videos on youtube etc. and I thought I should pass along the tip.

I dunno how others go about battling these annoying creatures at sea but I assume it is probably similar to how I've done it all along, which is one of several ways. I either unhelm the ship and draw my sword, then cast either Igni or Axii or Aard at them as they swing in for an attack, and thrash them a few times with my sword opportunistically and repeat until they're all dead - or I jump in the water and dive down about 10 feet and wait for them to come under water then I dispatch them with the crossbow - or a combination of these two methods. Axii works on them but is not very effective because while they will attack each other when under the puppet spell, they chase each other more than anything and do little damage usually. Igni usually does damage but they plummet to the water which extinguishes the fire and so it doesn't end up doing much damage unless you catch them right on the boat and give them the Igni firehose, that does the job but you can't rely on it too much. Also, often they get a few attacks in on you along the way and often topple you overboard into the water anyway, so you often end up fighting them underwater. Attacking them with the crossbow from the boat is mostly useless. At one point I used tracking bolts which worked well up until patch 1.05 or 1.06 at which point tracking bolts no longer track fuck all, they're just regular bolts. I dunno if that is a bug introduced in a patch or if the game just fucked up along the way some time and tracking bolts are broken now. At any rate even when they worked, they were only useful for dropping them into the water temporarily because they don't do much damage, but they used to help. Now I find the crossbow mostly useless for fighting these flying annoyances...

Up until now.

Now, I discovered that you can fire the crossbow WHILE PILOTING THE BOAT. Yes, while moving and steering the boat, Geralt can one-arm the crossbow and attack these flying annoyances. What's more, is that he seems to have some kind of auto-aim freaky shit going on, so you just hit middle-button and he aims at one of the random fucks and shoots at it. More often than not, one or two bolts will kill one of them with almost no effort. What ends up happening is that they surround the boat and then swoop in and try to attack the boat and tear it apart, but you just hit the crossbow button and he auto-aims at them and blammo, they're either insta-dead or they're insta-fucked-up and one more shot will take them out before they can do any damage. If you're using exploding bolts they'll possibly even take out 2 or 3 of them with one shot. This is odd because standing up in the boat you could probably hit one of them with 3 or 4 manually aimed exploding bolts and they'll take it like an NHL goalie with a coke and a smile. While steering the boat though, crossbow bolts appear to have double quad damage action going on. In the end, you can kill all of them in less than 10-15 seconds or so and don't even have to stand up. He could almost do it while reading a book.

So there you have it, the easy way to kill annoying flying mermaid bitches!

Nice!

What I found yesterday: got attacked by an old, named (forgot the name) Siren.
Had been upon a mountain, limited space, so I thought to bring her down using Aard ("z" to track her, etc.).

But, in my haste to change from igni to aard (always use the mouse wheel), I did not chose Aard but Yrden instead.

Should not work on a Siren - but this time it did:
the siren stopped, hung in the air (some 4 meters) over the Yrden circle.
So all I had to do was to move one step to the side, aim the crossbow >>> DOOM.

Don't know why Yrden had that much of an effect on this beast - got some greater Yrden runes on the equipment, might be that, or simple a nifty little bug.

Cool, yeah the bestiary gives some suggestions for oil/bombs but it isn't 100% complete. I find that both Igni and the dancing star and grapeshot bombs will damage many enemies in the game to varying degrees of success even when they're not listed in the bestiary so I'm sure it is true with other weapons/skills etc too for different enemies.

Yeah, I fought the siren you're talking about too. I think it was on Spikeroog if memory serves correct, either that or Undvik. They made her out to be a big badass, and I killed her with like 3 sword hits. I guess it depends on how powered up one is and what level difference.

One of the hardest enemies in the game to defeat IMHO are Earth Elementals. I found that they're very slow and pretty dumb though, and if you can put a tree or other object in between you and the elemental, you can hit them with igni, bombs, crossbow easily and the AI is so stupid it'll just stand there and take it for a long time without any reaction.

The meanest meanies of all time?

GARGOYLES!

"crept" onto one of them from the back, but only as long until he skyrocketed and came down on me hard.

Yeah, the first one I encountered was while I was with Kiera Metz I think, in some cave in Velen. It was a "you're locked in and have to kill this thing in a small space and can't get out until you do" situation and it was a tough fight with non-stop rolling on the ground to get away from the damn thing. I took several attempts until I finally felled the creature. I've only encountered one or two gargoyles since then but with Geralt at a higher level with better equipment and skills and they were far easier to put down. Was one of the toughest enemies in the game at first encounter though.

I completed the whole game first time....without xbowing drowners while underwater (I was avoiding them) and not shooting the Sirens :P Just imagine that xD haha....

I suppose that is possible too. Drowners are really low level overall as are sirens and harpies. They're dangerous when you first encounter them, but when you are leveled up enough and have good armor and whatnot, they don't do much damage to you at all normally, and that can be countered with potions/decoctions/signs to a certain degree anyway. There's the threat of being knocked off a cliff by some of them but with care that could probably be avoided too. It would seem out of character for a Witcher to be around such creatures and not kill them though. :)

aard while having piercing cold equiped and you can insta kill multiple at the same time