So, I’ve been away on vacation, and coming back, I wanted to give a fairly long bit showing how I’m writing examples into the text now. This is intended to be part of the ship construction section. There are a couple references to tables not included in this excerpt, but the meaning should still be fairly clear. Some of the rules mentioned can be modified by special attributes.
Seaworthiness: Seaworthiness measures how well a ship performs under adverse conditions. Each point of seaworthiness allows a ship to ignore 1d6 of damage from weather each hour. Each point also provides a +1 bonus to any Seafaring checks made to repair the ship. The Base Seaworthiness of a ship is also its starting Armor Class.
Decks: The default for a ship is a single deck, plus a hold for cargo. This deck has a Useful Length equal to 70% of the ship’s total length and the same width as the ship. A second deck with the same area can be added by moving one row down on the Length to Draught column (i.e. from the 40 to 1 ratio to the 28 to 1 ratio), while a third deck makes the ship less stable, reducing seaworthiness by 1.
Rowers: The required number of rowers to achieve the Base Rowing Speed is equal to the ship’s length in feet divided by 5, multiplied by the ship’s beam divided by 4. If this number is odd, add one to make it even. Required rowers = (Length/5)*(Beam/4)
The maximum number of rowers on a single deck is equal to the ship’s Useful Length divided by 3, multiplied by the ship’s beam minus 8 feet and divided by 2. If this number is odd, add one to make it even. Maximum rowers = (Useful Length/3)*((Beam-8)/2)
Example: A ship is being built as a 7 to 1 rowed and sailed ship, 112 feet long and 16 feet wide. It has a Base Seaworthiness of 3. It requires (22.44) = 89.6 rowers to travel at base rowing speed. This is rounded up to 90. On a single deck, it can have (.737.3*4) = 104.5 rowers, rounded to 105 and increased to 106 to make it even. This ship can maintain its base rowing speed with only a single deck of rowers.
Rowers can be carried on multiple decks if desired in order to add more power without lengthening or widening the vessel.
Example: While this galley isn’t intended for combat, it may find itself being used as a swift transport, so the designer adds a second deck of rowing benches. The ship can now hold up to 212 rowers, and has a draught of 7 feet, instead of the 4 feet it would have originally drawn.
Oars weigh one stone per two rowers.
Example: Fully equipped with oars for 212 rowers and 20 spares, the oars would take up 116 stone of weight. In normal merchant service, however, the ship will only carry 50 rowers’ worth of oars, weighing only 25 stone.
Tonnage: The tonnage of a ship is a complicated thing. For purposes of simplification, these rules use Builder’s Old Measurement to calculate tonnage, which is the length of a ship, minus 60% of the beam, times the beam, times the draught, all divided by 94. Each ton of ship provides 1 structural hit point (shp). Each ton of ship also provides 200 stone of carrying capacity.
Example: The merchant galley is 112 feet long and 16 feet wide, with a 7 foot draught due to the second deck. This means its tonnage is (102.4167)/94 = 122 tons and it has 122 shp. The ship can be outfitted with up to 24,400 stone of crew, equipment, and cargo.