This is a very realistic made RPG and not an action game Ben. It is also very tricky, so you have to build it up slowly and wisely. You can´t rush into it and expect to survive Ben. That won´t ever work out.
1. It´s not clever to rush for a bigger ship too soon because Rang 5 means nothing in this game and if you choose to have a bigger ship so soon, you will suffer of negative skills, even with a navigator. Also the shipyards won´t offer you bigger ships with such a low Rang. But if you absolutely want a bigger ship so soon, you can always try to attack spanish or pirate ships and if you succeed, you can change your Lugger against their ship in your menu after the fight. But i won´t recommend this so soon. Anyway for this kind of gameplay that you wish, you will need a crew that´s good in boarding (soldiers) and a lot of officers. For example 3 Boarders, a Boatswain and a Canoneer. Before you enter, you should always use Grapeshot in your cannons to minimize the enemies crew to have the best chance to survive a fight with a bigger ship.
2. To find and get the officers that you want and need, i would recommend that you save your game in front of a tavern before you enter it because the officers are random generated. It can take ages to find the right ones and you also have to be VERY PATIENT for that. Don´t hire the ones that tell you that they are the best in this and that, only take the ones that tell you that they shall be good in this and that or they will disapoint you for shure after some time.
3. If you want to avoid attacks from enemies when you are leaving a harbor, place your ship in front of a fort, go into seamode, engage and let the fort sink them for you, as i told you already some time ago Ben. It´s the easiest way and saves a lot of money too. Out on the sea i would recommend you to save many times and reload to avoid rat attacks and escape from enemies. This save and reload system is logged in your statistics but won´t have any negative effect on your gameplay at all like you mentioned in another tread. Also the loss of health is logged there but hasn´t a negative effect either.
I can only always repeat myself, that it is not meaningful to rush this game in any way. If you want to enjoy it, you have to build it up slowly and with patients step by step. Or maybe this game is not for you Ben. I would recommend to follow the advices from your brother Michel, to join one of the 3 companies that are available after the introduction and the 3 month of waiting time (the Dutch West India Company is recommended for beginners), to build up your skills like it´s meant to be and to collect the 1.000.000 pesos to free your brother afterwards. After that you should be strong enough for the freeplay that you seem to prefer. I´m not absolutely shure at the moment because i didn´t play the whole game through yet, but i have the feeling that it is made much more linear then AoP2CoAS:
I really wish you good luck in everything Ben