There are three ship yards in Porter's Bar, as befits a major  port, that  supports  large inland and sea-ward fishing fleets as well as  coastal and deep-sea merchant fleets.

All of the ship Yards in Porters Bar, like the other ship yard in Allium,follow the basic  rules for shipping as laid out in the 2nd edition PHB and DMG.  They  appears to be fairly compatible with both 1st and 3rd  edition rules (from the core books) as well.

Basic Shipping Guidelines
Combined Information from PHB and DMG 2nd Ed

Caravel: This ship was sailed in late Medieval/early Renaissance times and was the type of ship Columbus used to reach the New World. (It should be used only in late Medieval settings.) It normally has two or three masts and square sails. No oars are used. The typical caravel is 70 feet long and 20 feet wide. The normal crew is from 30 to 40 men. The average cargo displacement is 150-200 tons.

Coaster: Also called a round ship, this is a small merchant ship that hugs the coasts. This is a sailing ship, fitted with two masts and triangular sails. The average size is 60 to 70 feet long and 20 feet wide. The rudder hangs from one side. The crew is 20 to 30 men, and the cargo capacity is about 100 tons. Normally there is only a small sterncastle. A coaster is slow and not tremendously seaworthy, but it can carry large amounts of cargo with smaller crews than galleys.

Cog: This ship is a larger, improved version of the coaster, able to make ventures into the open sea. Like the coaster, it is a sailing ship with one or two masts, but the cog employs square sails. It is about 75 to 90 feet long and 20 feet wide. The crew is only 18 to 20 men. There is normally one deck and fore- and sterncastle. the cargo capacities of cogs vary greatly, but the average is 100 to 200 tons.

Currach: This is an early, primitive vessel. It is made from thick hides stretched over a wood-and-wicker frame. A single mast caries a small square sail, but the currach is usually worked by oars. It is normally 20 to 40 feet long. the crew is approximately six to eight and the cargo space is limited--no more than five tons.

Drakkar: The largest of the Viking longships is known as a drakkar or dragonship. Built for war, this ship stretches about 100 feet in length. Although a single mast can be raised, oars provide the main source of power. The crew of 60 to 80 men rows, one man to an oar. Up to 160 additional man can be carried for boarding and raiding. Due to its great size, a drakkar is not very seaworthy. This and the fact there is no space on board for many supplies (certainly not enough for 240 men) or sleeping quarters keep the drakkar close to the coast where it can put in for the night. Because of its cost and limited use, a drakkar is usually built by kings and rulers and is not used for the mundane task of shipping cargo.

Dromond: This ship is the largest of the Byzantine galleys. Although it boasts one or two masts and triangular sails, the main power comes from the 100 oars, 50 to a side. These oars are divided into an upper and lower bank, with one man per oar on the lower bank and three men on the upper bank. Thus, the total crew is about 200 men. The dromond is about 130 to 175 feet long and 15 feet wide, making it a very slender ship. The cargo capacity is around 70 to 100 tons.
A dromond can be used both for shipping and war. As a warship, a ram projects from the front just above the water line. Castles are built fore, aft, and amidships as firing platforms. The cargo space is then taken up by marines. With such numbers of men, it is a very dangerous ship to attack. A dromond is not a seaworthy craft, however, and usually sails in sight of shore. They beach at night like all galleys, since supplies and sleeping accommodations are very limited.

Galleon: This is the largest and most advanced sailing ship that might be available in the AD&D game. It should appear only in Renaissance-period settings. It is a sail-driven ship with three or four masts. There are normally three through decks (running the length of the ship), while the castles fore and aft have two decks. The average size is about 130 feet long and 30 feet wide. Crews average about 130 men. Although cargo capacity is about 500 tons, a galleon is mainly used as a warship. (In the real world they were fitted with cannon, something beyond the standard AD&D game rules.) They can easily carry men equal to their tonnage, making capture by pirates nearly impossible.

Great Galley: Built during the Late Middle Ages, the great galley is an improved version of the dromond. It is slightly smaller than the dromond, about 130 feet long and 20 feet wide. The main power comes from 140 rowers, one man to an oar, but is supplemented by three masts; this combination gives it better speed and handling. The cargo capacity is 150 tons. When outfitted as a warship, the front end is built as a ram and marines are carried instead of cargo. Like all galleys, the great galley is a coastal vessel, rarely venturing into open water. It is not seaworthy in heavy storms and waits in port for these to pass.

Knarr: This small ship was a common cargo ship of the Scandinavian region. It is 50 to 75 feet long and 15 to 20 feet wide. It has a single mast and a square sail. In times of poor wind, a few oars at the bow and stern can provide more power. The crew ranges from eight to 14 men. The cargo capacity is small, anywhere from ten to 50 tons. The ship is, however, relatively seaworthy and can be used to make long sea voyages (although it cannot be called comfortable). Its flat bottom makes it useful for sailing up rivers and estuaries, and it can be beached easily.

Longship: This is the standard Viking warship. It is more substantial than the knarr but not nearly as massive as the drakkar. An average longship is 75 feet long with 20 to 25 oars per side. Each oar is worked by a single man for a total crew of 40 to 50 men. There is also a single mast and a square sail. In addition to the crew, the ship can carry 120 to 150 men. A longship can be used for shipping, but its cargo capacity is only about 50 tons. It is, however, fairly seaworthy and can sail across the open sea when necessary.

Base move per hour is the average speed of the vessel under good conditions. Where two numbers are separated by a slash, the first is the speed under sail and the second is the rowing speed.

Emergency move is the top speed of the vessel in emergency or combat situations. For sailing ships, emergency speed is gained by putting on every yard of sail possible. Galleys and other oared ships rely on the strength of their rowers. This speed can only be maintained for short periods of time. Too long and rowers will collapse; masts, yards, and sails will break.

Seaworthiness rates the vessel's ability to remain afloat in dangerous situations, notably storms, hidden shoals, extended voyages, huge monster attacks, and rams. Any time the DM rules that there is a chance of sinking, he rolls percentile dice. If the roll is equal to or less than the seaworthiness rating of the ship, it remains afloat, though bailing or repairs may be necessary. If the roll is higher than the seaworthiness rating, the ship sinks.