It\'s important that you first check two things;
-Is the value of \"AI_WEAPON_AIMING_ACCURACY\" in your server.cfg file 10? This number affects how accurately can npcs and your bobby-AIs shoot. In my experience, if it\'s left at 10, they can expose and destroy ship cores at maximum weapon range way too easily. Best to set it to 9 or 8.
-Does the pirates have access to better ships, or only the basic Isanth model? They always come in groups, so you must make sure your ship is more powerful than their combined forces.
Beating a flock of Isanths isn\'t particularly difficult, but fighting a group of strong pirates with ships in similar mass to yours is more like pvp than hunting, with a very real chance of you losing, especially if the AI accuracy is high. And you\'ll need to do a lot of repairs even after victorious battles.
So, the basic rules;
-Your ship should always be far better than theirs.
-Place some containers on the ship. Pirates drop a lot of different loot that\'ll quickly fill up your inventory.
-Don\'t use missiles. They\'re really bad at catching small targets. By the time they do, you could have killed it with a same size amc.
-\"Shotgun\" style cannons have very low range unless they\'re built of rather long lines. Might be too heavy for the ship size you wanted.
After that, you should decide your combat style, and build your ship according to that. I\'ll list a few examples.
1. - Sniping may be a cheap, if somewhat risky method. You\'ll need powerful, long-range, rapid fire guns to kill the pirates as soon as their navigation markers appear and never let them close enough to shoot at you. Your cannon must be strong enough to break blocks in one hit. Must have far greater range than the enemy. Must reload quickly, to make sure enough bullets hit the target (you\'ll miss a lot at long range.) Something about 1500 range without redistributing any points, and it\'ll be quite lethal.
If AI accuracy is high, you might want to consider to build your main gun as a turret docked to a green \"ship\" dock, but the AI still set as \"turret\", and to fire at your selected target. It\'ll aim far better than a player can. Using more than one will greatly improve your killing power, but also increase the cost and size of your ship.
2. - Dogfighting needs more expensive ships. They must be compact, to avoid turn-speed penalties (shouldn\'t be longer than 80 blocks in any direction, or the pirates will dance around you and you\'ll never target them), but must also be bulky, so you can fit them with enough shields, power gen., thrusters and cannons. 2:1 thrust-to-mass ratio is vital to outmanouver the enemy. You should cover everything with hardened hull. Don\'t leave anything exposed. Armored thrusters, armored gunbarrels. Hide the core and weapon computers in the center of your ship. Get 100K shields; No matter how well you fly, if there\'s more than one pirate trying to shoot you they will succeed. You may want to add one or two medium sized turrets too. ( no less than 20k shields each, or they\'ll break all the time. Must have enough power regen to let you shoot and fly at once for a long time.
3.- A platform for automated weapons is a very expensive, unstoppable turtle of death. Build it as large as you can, and don\'t care about turning speed. It\'s not a problem if the ship is a little slow either. You don\'t even need guns in the ship\'s main body, but build as many turrets as you can; The pirates will shoot at all of them, so the more turrets you have, the less damage will a single one have to suffer. A few large ones that will do most of the work and break blocks in one hit, several medium ones to help keep your target\'s shields depleted, and if there\'s room, some small defense turrets to make sure you don\'t have any blind spots.
The ship itself needs double thick hardened hull where possible. Hide the core and the docking enhancers as deep as you can - If even one enhancer breaks, it\'s turret will fall off. Have as much shields as possible, both on the ship and the turrets. Add a lot of power regen to the ship, but only one block to the turrets; They\'ll take the power they need from the ship, and there\'ll be more room on them for cannons and shields. (Their shields won\'t work if there isn\'t at least one power generator).
Place your turrets evenly; Some on the top, and some on the bottom of your ship, so they can see all around you. Make sure they don\'t obstruct each other\'s line of sight. For example, if you place a turret behind another one, it should sit on a raised platform, so it can shoot above the first.
You can even combine these designs, or come up with one of your own. However that 1500 mass you aim for will somewhat limit your possibilities.