@threeghost97
I've soloed the skeleton fleet countless times. Even during times when it was more difficult to fight a skeleton ship. They have been nerfed more than once and in different ways. Don't feel bad if you have trouble with them. Even seasoned veterans can have issues with a single ship.
Don't look at them as broken, unbeatable death sentences because they are not. They also aren't pushovers. They provide a decent challenge and with a little knowledge and practice, you will have minimal issues with most ships you encounter.
If you solo a sloop, keep in mind that it's the easiest to keep afloat. Boarding up holes can wait in battle. Always bucket first and don't be afraid to leave a couple holes for a short while. Especially if they are in the back half of the ship. I used to have my bucket hotkeyed solely for ship battles.
If you are being fired on, take cover so you don't get knocked off. If you find yourself in their fire too much, ram your ship into theirs. When both ships are side by side, they won't fire cannons at you, just eye of reach and blunderbuss. With both ships side by side, you can focus on healing, filling your pockets, repairing, and bailing without worrying about them peppering your ship further. If it's ever possible, toss the water from your bucket onto their deck. Every bit of water adds up and brings them closer to sinking.
Many people know that ballistballs are very useful against galleons but only if used correctly. A ballistball by itself will do nothing. Always aim for the lower deck with cannonballs, BUT if you hit the top deck on accident a few times within a few seconds, THEN use a ballistball so those holes you made will actually take on water before they are repaired. If the ship is already half full, the ballistball is again useless. The ship will already be sitting low in the water.
After putting a few holes in their lower deck or anywhere that the holes will take on water, hit them with a green ball. Grog balls, sleep balls, and jig balls will stunlock the skeletons keeping them from repairing.
Firebombs on the cannons will kill the skeletons trying to fire on you. Try to keep the deck ignited for this reason.
Blunderbombs fired from a cannon have a significant effect on a ship, hitting a ship near the bow or stern from the side will actually cause it to turn. You can use this at times to turn their ship so that yours will no longer be in their range of fire.
It's common for a skeleton ship to have a keg inside somewhere. Your first few cannonball shots should be spread out along the hull of the ship so any kegs will ignite, significantly speeding up the process of sinking them. Also when a skeleton ship first spawns, the skeletons won't actually do anything for a few seconds. If you are ready on the cannons, and you hit them all across the bottom deck as soon as they emerge, they will take on significantly more water than normal because the skeletons won't even start to repair them for a few seconds. Once they start, you already have a line of holes from bow to stern taking on water, and if you can keep up fire, the holes will get bigger, and the skeletons will get knocked back off the holes and even killed.
When a skeleton sloop spawns to attack me, I aim every shot towards the left and right edge of the enemy cannon. The blast knocks the skeleton off the cannon and eventually kills him, keeping them from firing a single shot, while aiming just to each side puts two holes side by side below deck that keep getting larger with every other shot. Any time a skeleton tries to repair below deck or fire above deck, my next shot knocks them back. They always sink after 10 cannonballs and never fire on me.
Skeleton ships are constantly trying to get your ship in their cannon range. If you let them, they won't stop firing. You can't stay still and you can't sail in a straight line without them lining you up and lighting you up. If you have trouble sailing while dealing with everything else, just put your ship into a hard turn with the sails raised up around half way. This should make it more difficult for the skeleton ship to get a shot and let you concentrate on other things than the helm.
I suggest attempting the skeleton fleet. You will be fighting them on your terms. Nothing to lose. An advantage of the fleet is you can always sail out of the battle to safety and return whenever you want. Even if you sink, you can come back as many times as you want. It may take a long time but eventually with enough persistence, you will sink them all and earn the treasure. More importantly, you'll gain some experience and knowledge on how to fight them better. Especially if you sink, you'll know what not to do when you come back.