you will run the risk of being busted, and attacking a ship that is heavily armed by those armaments are hidden until you get too close. Plus pirates usually have prices on their heads and have to deal with pirate hunters, bounty hunters, and their own crew turning them in.
There is also the chance of blowing up the other ship, or getting killed when the other ship returns fire. There are ship combat rules to follow. Also person to person combat rules to follow.
Almost everything is a dice roll or GM decision. The GM or Game Master has to decide what is possible or not, and if a dice roll needs to be made to attempt it. Sometimes we fail.
If our group ever gets a game together, I can invite you to watch it. Usually we meet on a weekend, but not recently due to hardly anyone having the time to do so. You can decide for youself if the game is realistic or not. :)