Common knowledge for the Pirates! series veterans but FYI for new players.
Normally, attaining a rank will provide you with a meager 50-200 acres of land. Purposely postponing a rank while actively attacking enemy ships and ports of that nation will greatly increase the wealth (acres of land) you receive from that nation when you do decide to receive a rank, thus it is possible to receive thousands of acres per rank achieved this way.
Retiring with a whole lot of stash as dual benefits on your personal wealth as well as your crews morale on your next voyage (they tend to be happier longer since you have a nice credit history report). Maximum effect to achieve this is done cruelly by simply killing off most of your crew before you retire at a port, thus the share of profits will be substantially greater. The easiest way to achieve this (killing your crew
fast) is by boarding a nearby port or ship and entering fencing mode combat. Fight your opponent until he almost loses and go into defensive mode by blocking every attack without attacking or counter-attacking, until most if not all your crew dies. Mind you that when your crew size gets substantially low (below 5 men), the opponents attack reaches almost god-like speed, thus it would be advised to defeat him near that number. Also note that for some apparent reason, even if you do succeed killing off all your crew, some of your crew is mysteriously resurrected thus impossible to retire with a minimal crew size less then 5-10 crew members (numbers varies, uh at least I recall). Last note, when attempting this technique; avoid attacking large or medium sized ports or even some small sized previously unplundered ports. This will only get you into melee combat mode. Attacking a port and automatically entering fencing mode (with the ports guard captain) without entering into melee mode, only occurs when a town port has been greatly reduced by numerous previous plunder attempts. So previous planning may be required for this approach.