Not all weapons are available at the beginning of the game, since Weapon Smith's production is tied to the experience level of the Shipyard. As the shipyard improves, the Weapon Smith starts making more advanced weapons (such as cannons).
Weapon Smith requires specific materials to operate:
Leather
Hemp
Timber
Iron Goods
If any of the goods is not available in town, his production will stop.
Ship's Weapons
Any trader can purchase ship's weapons in a city with a trading office.
Cutlasses are used to equip sailors on ships that might board another ship in naval combat (cutlasses just need to be loaded on the ship). They significantly improve the combat performance of the crew.
Catapults, ballistas, bombards and cannons are placed on ships with proper weapon slots. If a ship doesn't have any weapon slots, they can be added by improving the ship at the Shipyard.
The damage of ship weapons depends on the distance between the ship and its target. Small distance results in higher damage, and vice versa.
Different weapons also tend to be slightly more effective at longer or shorter ranges. Ballistas, for example, are noticeably more potent at extremely close range compared to cheaper weapons. Still, their average damage is higher than that of less common weapons. This essentially means that more expensive weapons are generally worth the investment.
During the history of the game there have been many speculations about certain weapons' supposed ability to be more effective against the crew or the hull of the ship. As a result, many players were convinced that using catapults would make it possible to capture ships while inflicting less hull damage. However, it has been shown that such mechanics are not implemented in Patrician 3, where it's impossible to kill the crew without damaging the hull.
The following diagrams show the short and long range damage capabilities of available weapons.
Note: these numbers are not actual values used by the game. What does this mean?
Small Catapult  Sell: 169 | Damage  | Damage |
Small Ballista Sell: 250 | Damage | Damage |
Large Catapult Sell: 407 | Damage |
Large Ballista Sell: 652 | Damage |
Bombard Sell: 896 | Damage |
Cannon Sell: 250 | Damage | Damage |
Hand Weapons
Hand Weapons are used to equip Town Guards.
The rank of Lord Mayor allows traders to buy weapons in their home town, while an Alderman can purchase them in any city.
A Lord Mayor can assign a priority to one of the hand weapons. The Weapon Smith will stop producing all ship's and hand weapons to make that particular weapon.
Ties to the Underworld
You can meet Weapon Smith in the tavern as well, under the guise of the Weapons Dealer. Talking to him, however, will result in a fine (unless you are Alderman).