GURPS Low Tech Notes: Galleys, Naval Encounters,

Galleys

Galleys are long narrow oared boats, sometimes with sails. They were used from BCE to the 1500CE. They were measured in total number of oars, and rarely by their dtons (which should have been noted), so you can expect them to be even and rounded numbers. You will find 20, 30, 50, 100, and 200 oars. Rare capital / flag ships being more than 200 oars. Ships are measured in Displacement Tons, Oars and Masts.

In the course of the centuries, these galleys evolved from simple square Sails, to multi lanteen or triangle sails. Ship engineering tried to solve many puzzles: height of the mast vs the capability of the foundation to sustain and the forces that affected it, size of the ship, carrying capacity, limitation of building material, turn around time,  storage of provisions, war-augmentations, navigation, etc... The increase of speed was about 20% in about +1500 years, but naval traditions and additional ports allowed farther and farther ranging.

Galleys follow a Beam to Length ratio of about 1:8+ because of the nature of its propulsion. You will know the era of the galley by the shape and type of sail, and the number of masts. The older the model the more reliant of oars and only one mast, near the emergence of the age of sail they are multi-masted with lanteen sails. Shipbuilding peoples made ships based on the wood they had, and they exported this ships to various nations that could not produce it themselves. Certain ports had to have everything just right: a river to feed it logs, plenty of trees along this river (ideally on hills to roll it down), and a good harbor from weather. Once you identify the shipbuilding ports, you can sketch the economics of ship building of various factions and powers.

Galleys are a coastal ship and was always sailed close enough to shore because it had so much man power to feed and water. The more oars relative to dtons the faster they become but the shorter their endurance. 30 oar ships, like the Viking ships can have 15 days of supplies if they were 15dtons (less if they bring armor and weapons), while 50 oar ships have 7 days of supplies at 20dtons (both assuming passengers). This meant wasting a two days provisioning and basing your navigation on how many "port" hops you would have to take. Seasons determined how many days it took for one particular direction. Ancient era ships used earthen jars, added about 30% to the weight and bulk of the supplies. You can say it removed the same proportion to its supply range.

What I love about galleys is the human heuristics that limited it. Rowing despite many idealizations from armchair historians or gamers worked with very very finite resources. It doesnt help that its an upper body exercise, which the human body had efficiency limitations compared to running. These Rowers will be needing more than the +2000 cal per day diet and a generous amount of protein (typically from wheat and fish) if their captain wanted his "cogs" to be working better longer. Wheat crackers which have the calorie density of x8 of oats (calories per grams)

One more important aspect of sailing is Navigation, you can't have just ONE navigator. You needed 3-5, for shifts and incase one gets injured. Navigators are scarce, you can imagine a captain having apprenticeships if he wants to maintain a steady supply. There are only stars, landmarks by day, and the sun, to navigate and you need a ton of experience measured in the number of sailing seasons and trips the sailor has made. Until the compass found its way west, you will be at the mercy of manpower scarcity of good navigators or you will have to delay and delay until the season changes.

3-5 Navigators with some crew still awake and available 24 hours meant being able to travel 24 hours instead of anchoring near land at night. When sails improved much during the medieval era, you have more and more productive sailing ranges. In clear night skies with so many stars, Sailors are guided with much greater precision. An asset is a Sailor with some Astronomy, Mathematics, and able to write, and a crew literate and able to learn and apply.

War Ships can be distinguished from Non-Warships by skilled sailors. Warships have castles, ramming prow, and fortified. Warships are more evident from shields along its side OR if disguised, will be evidence once you glance the inside, in allocation of supplies and the dedication for rowing seats. 20 dtons with 30-20 oars are optimal for trade in relatively secure waters. 50-80 oars are for long distance trade and security against attacks.150- 200 oared ships would have be at 90-130 displacement tons and designed to carry 100-350 elements for the same duration.

Naval Combat. 

Elaborating Naval combat,

• Map Preparation. 
• Various time scales maintain a number of hexes of movement. Shift scale if the ship is 1 turn away and gaining.   
• An hour Scale is 1.6km or 1mi per hex. Note the Ship's visibility range, once out of visual range and with an hour and cannot catch up, the ship is considered to have escaped. 
• A 15 minute Scale is 0.9km or 0.55 mi per hex.  
• 5 minute sacle per turn would be 0.3 or 0.2 miles scales. Shift to this scale when the 
• 1 minute scale is 60m or 66 yards. 
• Token Visibility ranges remain the same.  
• Visibility. The mast is what determines the visibility. the bigger the ship the taller the mast and the farther a crewman can peer over the horizon. (the Mast in Meters^0.5)*2.57km. 
• The Ship Token 
• Maneuvering and Positioning. 
• Movement
• Steady Pace (like Hiking) - Ship Move * 1.6kph or 1mph at 1FP per hour. 
• in 1 hour, cover a distance equal to a number of 1.6km or 1mi Hexes equal to the ship's move. That would be hexes with an area of 0.55 sq. km or 0.21 sq mi 
• Fast Pace (like Paced Running) - Ship Move * 3.6kph or 2.25 mph at 1FP per 15 minutes. In 15 minute travel a number of 0.9km or 0.56mi hexes in 15 minutes. 
• Tide and Wind direction (penalizes movement towards a particular direction). 
• simplify by adding or subtracting 1 hex of move per direction. 
• Time, Distance, and Arc of movement covered by the Ship.
• Sail, Oars and Both move *   
• Engaging: Resolve as Mass Combat or Below

Alternative to Resolving it as Mass Combat

• Ramming. 
• you need a ramming prow. Getting into position is contests of Shiphandling with ship handling modifiers.  
• Ranged Attacks. Side facing you get the total Size modifier of the ship, front or rear, -4 to SM modifier (these ships are very narrow, of 8:1 beam to length ratio). 
• Archers (note number of Volleys) 
• B557 for vehicle hit table, 
• Fire Arrows B410 very low chances to start a fire, penalty to hit. B433 Catching Fire Rules, basically you need to deal 10+ points of fire damage to catch fire. Crewman check to douse a fire. So multiple fire attacks has the best chance of burning a ship, fire attacks is really to shake up the crew and sow confusion and disorder as they try to put these fires out. Crewmen busy putting fires out means, crewmen who cannot row to maneuver the ship.  
• LT84 Incendiaries. Large Fire Arrow bolts more Fire. Fire arrow is 1 burn / sec. larger and larger arrows can do more damage. The square root the number of times heavier the fire projectile is to get the new fire damage. 
• A 1lb ballista would be x10 heavier than an arrow for 2x the damage. 1d-3 damage (1 dmg)  is  now 3 for 1d-1 burning. 
• An Arbalest is at x5 the weight would deal the 1d-2 burning but have the best range of delivery. 
• A 180 ballista is 1800 heavier for 2d x 5 burning damage which can only be placed on Naval defense wall or on a 200dton ship. 
• Ballistae or Scorpions (note number of Volleys and the time scale)
• Boarding Actions. Its best resolved via GURPS mass combat at this point. Although the GM can always quickly draw up the two ships if the players are not picky and run the combat. 
• Pulling in the enemy ship. Opposed Shiphandling check, the instigator with the right tools get '+2.
• Fighting on board. resolve as a mass combat small skirmish. (hella faster and simpler)
• Fighting adjacent. resolve as a mass combat small skirmish. (hella faster and simpler)

Ship Notes

• Oars and Size. Not all ships with a fixed number of oars are the same. Some are up to 100% in volume (you will notice that its not struggling for space for its oarsmen) but are slightly slower because the added volume allows it to support greater and greater sails. 
• Simply Use descriptors of Light (minimal tonnage/displacement, will be noted), Heavy (50% heavier), Very Heavy (100% heavier, typical merchant ship). 
• Ancient Vessels are typically Light when below 30 oars, and Medium Frame at 30 oars and up. Often they are Heavy Frames.  
• Viking Ships can be Extra Light and Light Frame in larger sizes, but they only have a maximum of 80 oars galley size and with only one square sail. This means they can carry more as their empty weight goes down, and their Loaded weight becomes unchanged.
• Extra Light Ships have about 50% lighter empty weight.    
• TL3 Medieval Galleys below are Medium Frame and Standard Materials. Venice and Byzantine Ship builders learned to use Lanteen Sails (up to 3 masts) and Extra Light Frames for up to 100 oar galleys. Merchant City State can make similar ships up to 70 oars.  
• Mixed Fleet. Slower moving Supply ships with a higher Displacement to Propulsion ratio compared to Faster ships which has more Propulsion vs Displacement means you can have a fleet of small fast ships accompanying larger ships which allow these smaller ships extended range. 
• 50 oar ships with only 13 displacement tons have a move of 4.75 vs a 50 oar ship with 50 oar ship with 26 displacement tons which have 4.16 move. Combined they have a shared 9 man day range but travel at the pace of the slower ship. When there is a need the lighter ship can pursue slower quarry or recon for the larger ship!  
• Mass Combat, the minimum Maintenance Cost of the Ship is the number of Crew calculated as  Sappers (which are the same). The Crew, when fighting on land is calculated as Sappers and use Sappers to calculate the cost of training more crew. 
• I've included Mass Combat Stats in this article because the differences are very remarkable. 

Crews and Passengers

• Assuming 160lbs or 73kg per person. 
• Rower with just Light Enc. worth of possessions is at 82kg or 180lbs.
• Passenger with just Med. Enc. worth of possessions is at 100kg or 220lbs.  

Supplies Breakdown. 

• Largest Earthenware Jars with packing material (LT34). 14lbs or 6.4kg per gallon (or one man day of water) and $2.5. 
• Large Water Barrels with packaging material (LT34).  11.6lbs or 5.3kg per gallon (or one man day of water) and $10.5. 
• Food plus packaging (4 meals) 2lbs or 1kg; $8 per Man day.
• 15lbs or 7.4kg per man day in TL1
• 13lbs or 6.3kg per man day in TL2-3
• Ship - Crew and Passenger Weight. Allocate other supplies, and divide the remaining weight according to the 

Every Navigator is 6 hours of good Navigation, or 8 hours of -1 navigation, or 10 hours of -2 navigation, or -4 penalty for 12 hours. 

Assume each Rower is 160lbs or 73kg

Rower carries possessions of about Light encumbrance 20lbs or 9kg. 82kg per Rower. 

Marines and VIPS carry posessions about medium encumbrance or 60lbs or 27kg. 100kg per Marine and VIP. 

Light Dromon (13 dtons, 50 oars)

Visual references of the Dromon makes it really a "destroyer" moving quickly to intercept and swarm slower enemy ships. This ship has a range of 1 man days worth of supplies. It is really meant for defense of a port. If it will travel it will need to be accompanied by a supply ship. 

• ST/HP 52
• Hnd/SR: -3/3
• HT 11
• Move
• Oars 0.3 / 5
• Sail 0.05 / 6
• Oars and Sail 0.6 / 7
• Loaded Weight: 10 tons
• Empty Weight. 6.7 tons.
• 13 displacement tons. 
• Load: 6.3 tons
• Size Modifier: +7
• 30m (90ft) : 4m (12ft)
• Occupants. 
• 50 rowers, 
• 3 crewmen, plus captain. 
• 10 passengers 
• DR 2
• Range: 
• 2 man days (65 occupants in all). 
• Cost:  $22,000
• Cost to Raise +$180k / $36k
• Locations: 
• 3 Masts
• A ramming prow. Rowing the ship deals 3d cr damage.
• Notes: 
• Ramming Prow.  
• 5 km or 3.2 mi visibility

Heavy Dromon (20 dtons, 50 oars)

This Dromon is a proper fighting vessel with range, armor, and the ability provide Archers a platform to fight. Slower than the Light Dromon, this is still a fast ship, and difficult to mistake as anything else but a war ship (the Castle and the Prow). 

• ST/HP 57
• Hnd/SR: -3/3
• HT 11
• Move
• Oars 0.3 / 4
• Sail 0.6 / 6
• Oars and Sail 0.6 / 7
• Loaded Weight: 10 tons
• Empty Weight. 6.7 tons.
• 19.5 Displacement Tons
• Load: 8.3 tons
• Size Modifier: +7
• 37m (111ft) : 5m (16ft)
• Occupants. 
• 50 rowers, 
• 3 crewmen, plus captain. 
• 10 passengers 
• DR 5
• Range: 
• 7 days
• Cost:  $28,000
• Cost to Raise +$180k / $36k
• Locations. 
• 3 Masts
• A ramming prow
• Rear Castle (fits 10 Archers)
• Notes: 
• Ramming Prow. Rowing the ship deals 3d cr damage.
•  5 km / 3.2 mi visibility

30 Oar Small Trader (20dtons)

A ship of minor trading cities and of smaller merchant families. This is very efficient in Overhead to revenue output, this can make up 2/3 of all trading vessels encountered. 

• ST/HP 63
• Hnd/SR -3/3
• HT 11
• Move
• Oars 0.1 / 4
• Sail 0.3 / 5
• Oars and Sail 0.6 / 6
• Loaded Weight: 10 tons
• Empty Weight. 3.1 tons.
• 19.5 Displacement Tons
• Load: 11.9 tons
• 3.4 tons of supplies
• 5.17 tons of trade goods
• Size Modifier: +7
• 37m (111ft) : 5m (16ft)
• Occupants. 
• 30 rowers, 
• 1 crewmen, plus captain. 
• 6 passengers 
• Instead of Goods, additional passengers would be 0.1882 tons (including 14 days food and 27kg/60lbs of luggage). This translates to 27 people being moved for 14 days (or 32-40 slaves). 
• DR 2
• Range: 
• 14 days. 
• Cost:  $7,500
• Cost to Raise +$120k / Maintain $24k
• Locations. 
• 2 Masts
• Notes: 
• 5 km or 3.2 mi visibility

80 Oar Large Trader (40dtons)

A ship of more powerful merchant families. The additional oars also mean additional Security and a much farther 

• ST/HP 67
• Hnd/SR: -3/4
• HT 11
• Move
• Oars 0.1 / 4
• Sail 0.4 / 6
• Oars and Sail 0.5 / 6
• Loaded Weight: 30 tons
• Empty Weight. 8.5 tons.
• 39.5 Displacement Tons
• Load: 21.5 tons
• 6.8 tons of supplies
• 6.76 tons of trade goods
• Size Modifier: +8
• 40m (120ft) : 6m (18ft)
• Occupants. 
• 80 rowers, 
• 5 crewmen, plus captain. 
• 16 passengers 
• Instead of Goods, additional passengers would be 0.163 tons (including 10 days food and 27kg/60lbs of luggage). This translates to 41 people being moved for 14 days (or 92 slaves). 
• DR 2
• Range: 
• 10 days. 
• Cost:  $20,000
• Cost to Raise +$270k / Maintain $54k
• Locations. 
• 3 Masts
• Bunks
• Notes: 
• 5.7 km (3.6 mi) visibility

Capital Ship (200dtons, 300 oars)

The capital ship able to support itself and flanked by many other auxiliary ships that support lighter and faster ships. This ship will plow through an enemy fleet knocking aside smaller ships. If it is not carrying any troops it can stand to have 4x 180lb ballistas burning down smaller ships with relative ease at a range of 430 yrds or 10 elements of Arbalests with each castle firing 20 firebolt volleys per minute at 450 yards.  

• ST/HP 95
• Hnd/SR: -4/4
• HT 12
• Move
• Oars 0.1 / 5
• Sail 0.2 / 6
• Oars and Sail 0.3 / 7
• Loaded Weight: 30 tons
• Empty Weight. 8.5 tons.
• 39.5 Displacement Tons
• Load: 21.5 tons
• 6.8 tons of supplies
• 6.76 tons of trade goods
• Size Modifier: +9
• 70m (210ft) : 10m (30ft)
• Occupants. 
• 300 rowers, 
• 59+1 crewmen, plus captain. 
• 60 comfortable passengers 
• 350 cramped accommodation passengers
• DR 7
• Range: 
• 8 days. 
• Cost:  $1,500,000
• Cost to Raise (including oarsmen that fight) + $1,080k / Maintain $216k
• Locations. 
• Ramming Prow 5d+2 damage
• 3 Masts
• 60 Bunks
• 14 Cabins
• 8 Luxury Cabins
• Notes: 
• 7.2 km (4.5 mi) visibility

Naval Encounters Table

This is only along "Sea Lanes"

3-4 - 1d6 80-Oar Large Trader, with 2 30-Oar Small Traders per larger Trader.

5-6 - 1d6 30-Oar Small Trader

7-8 - 80-Oar Large Trader

9-12 - 30-Oar Small Trader

13-14 - 1d3 Light Dromon/War Galley, if there are 3 Light Dromons, roll 1d6 - on a 1. Add a 30-Oar Small Trader acting as auxiliary.  

15-16 - Heavy Dromon/War Galley, 

17-18 - 1d6 Light War Galley, 1d6 Heavy War Galley, 1 30-Oar Small Trader (serving as auxiliar) per 2 war ships or 2 Heavy Trader for every 3 war ships.

Note that Dromons or Light War Galleys are Fast but have Low Range! They may force an encounter if they have the wind, current, and visibility advantage.