If you hit another ship (with canons or normal weapons) you lose 50k naval fame (karma). Usually that means you'd got instantly negative/red. While you are red, you can't interact with wharf managers (except on pirate island), that means you are locked out of most sea content. The only ways to recover naval fame at the moment are by hunting sea monsters or doing a repeatable quest in Velia. The problem is you regain so little naval fame that it would take months to go back to positive karma. If your boat got sent to a wharf, you can't even use it anymore...

There needs to be a NEW way to recover karma faster. I suggest fighting pirates on some of the islands, or even some sort of pirate bosses (scrolls only for negative sea fame players). The way the system is atm, it's broken. Players SHOULD be punished for PKing, but definitely not to this extent.

sea of silence, 100k - 150k an hour.

.Karma Pets, Karma Scroll, Guild Buffs.

Also -50k doesn't even put you close to Negative Sea Karma. you have 300k at max, so unless you never capped your Sea Karma and some how flagged and attacked a player.... this all seems sus.

The Sea Karma system is fine, what it sounds like is you don't have a very good ship. When you have a Carrack even in meh Greens, you can farm up 300k Karma pretty fast. Honestly imo the Karma system should be harsher since I can go red, pull my pets out and pop a scroll and be back to positive in under an hour.

I killed a cog for fun, it was a oneshot with an epheria sailboat : results im now -250k 
its not -50k per kill its way more

So then it was supposed to be fun? For the both of you or just for you?

When you shoot a cog out of safe zone in front of Velia wharf, it's nothing but helping other players. 
yes, the cog can block a carrack. And no, the owner of the cog does not lose anything.

But it's not what is discussed here. As you can see, naval karma only impacts people without knowledge making it super hard for them to recover while people deciding to go red don't give a fuck about it because they have their ways around it. In that way, i agree that red penalty is not enough but it's a way of playing and there is no benefit from being red. People on land can have fun being red, on sea, you can't. You can"t oneshot a sailboat. On land, it's not family shared... etc
When you do stuff without playing the game and not listening to the ones you do, you just create problems for people who made a "mistake". The mistake was not attacking an unprepared player, it's his lack of knowledge about it.
i grind sea stuff flagged and will sink any ship i see if i feel like it but i will never sink a cog or a parket sailboat near sycraia? Why because it's a waste of karma, while on my grinding spot, i just don't care. i have no repercussion there being red as you can't be sunk (were your gear downgrades) if you're not willing to. So no punishement for me in being red. i'll just slowly get my karma back until next one passes by and realises it's not a good serer to be on. Monster density is so low that some servers are known to be used by one player... and if you want to get the spot, you will have to lose karma and end up without the spot anyway lol

The naval karma is bugged since release and they won't fix it. I sent several tickets, they just don"t care.
You lose -50k when you tag a ship, after roughly 30secs, you will lose more 50k, and so on... So you can go red on a single ship defending your sea grinding spot and not even sink the other.
When you sink any ship (raf and cogs count there too) = -200k 
and if you kill the owner of the ship, you will get approx -200k too

There are many tricks to get people going red or to sink some newbies without wasting any karma.
The problem is the naval system does not work as intended as it just discourages players into fighting and the few willing ones know perfectly how it works and have no problem going red.