🌊 Underwater Adventures
Swimming and Breath
Holding Breath: A creature can hold its breath for a number of minutes equal to 1 + its Constitution modifier (minimum of 30 seconds). When out of breath, a creature can survive for a number of rounds equal to its Constitution modifier (minimum 1 round). At the start of its next turn, it drops to 0 hit points and is dying.
Swimming: Each hour of swimming requires a DC 10 Constitution saving throw. On a failure, the creature gains one level of exhaustion. Heavy armor gives disadvantage on the check.
Depth and Pressure
| Depth | Effect |
|---|---|
| 0-100 feet | No special effects |
| 100-200 feet | Equivalent to 2 hours of swimming (exhaustion risk) |
| 200-300 feet | Equivalent to 4 hours of swimming |
| Each additional 100 feet | Add 2 hour equivalent to swimming time |
Underwater Combat
- Creatures without swimming speed have disadvantage on melee weapon attack rolls unless using dagger, javelin, shortsword, spear, or trident
- Ranged weapon attacks automatically miss targets beyond normal range
- Ranged weapon attacks have disadvantage even at normal range (unless weapon is crossbow, net, or thrown weapon like javelin)
- Fire damage is halved underwater
- Creatures fully immersed in water have resistance to fire damage
Visibility Underwater
| Water Clarity | Light | Visibility |
|---|---|---|
| Clear water | Bright light | 60 feet |
| Clear water | Dim light | 30 feet |
| Murky water | Any light | 10 feet |
| Any water | Darkness | 0 feet (heavily obscured) |
Random Undersea Encounters
| d100 | Encounter |
|---|---|
| 01-10 | 3d6 quippers (piranha-like fish swarm) |
| 11-15 | 1d4 steam mephits |
| 16-25 | 2d4 sahuagin (aquatic humanoids, usually hostile) |
| 26-35 | 1d4 giant octopuses |
| 36-45 | 2d10 merfolk (usually neutral, may trade) |
| 46-50 | 1d4 sea hags |
| 51-60 | 1d6 + 2 giant sea horses |
| 61-70 | 2d4 hunter sharks |
| 71-80 | 1d4 water elementals |
| 81-90 | Ancient shipwreck (contains treasure and monsters) |
| 91-95 | Underwater cave or grotto (possible lair) |
| 96-00 | Giant sea creature (whale, kraken spawn, or dragon turtle) |
⛵ Sea Travel
Navigation Methods
Dead Reckoning: Navigate by landmarks and estimated speed. Easy near coast (DC 10), difficult in open ocean (DC 15). Requires navigator's tools proficiency.
Celestial Navigation: Use stars and sun position. Requires navigator's tools proficiency and clear weather. DC 12 Wisdom (Survival) check. Storms and cloud cover prevent this method.
Failed Navigation: Ship drifts off course by 1d10 miles per day in a random direction. Crew doesn't realize until landmarks are spotted or celestial navigation succeeds.
Weather at Sea
| Weather | Effect on Travel |
|---|---|
| Clear Skies | Normal travel speed, good visibility (10 miles from crow's nest) |
| Strong Favorable Wind | Sailing ships: +1 mph to speed |
| Strong Contrary Wind | Sailing ships: -1 mph to speed (minimum 1 mph) |
| Dead Calm | Sailing ships can't move (must row or wait) |
| Fog | Visibility: 1d4 × 100 feet. Navigation checks have disadvantage |
| Storm | Half speed, rough seas, visibility 1d4 × 100 feet. Risk of damage (see below) |
Visibility at Sea
From crow's nest in clear weather: 10 miles
In fog or storms: 1d4 × 100 feet
At night with moon: 1 mile
At night, no moon: 500 feet
Random Encounters at Sea
| d100 | Encounter |
|---|---|
| 01-10 | Passing ship (friendly merchant vessel or naval ship) |
| 11-20 | Pirates (hostile ship, 2d10 bandits + captain, demand cargo or attack) |
| 21-30 | Merfolk pod (curious, may trade or ask for help with sea monster) |
| 31-40 | Sahuagin raiding party (2d6 warriors on hunting mission) |
| 41-50 | Giant shark (hunter or reef shark stalking the ship) |
| 51-55 | Dragon turtle (ancient, territorial, demands treasure toll) |
| 56-60 | Griffon or harpy flock (flying overhead, may attack if hungry) |
| 61-65 | Storm giant (traveling alone, usually peaceful) |
| 66-70 | Kraken tentacles (ship is attacked by kraken from below!) |
| 71-75 | Underwater ruins visible (ancient city, possible treasure/danger) |
| 76-80 | Floating wreckage (recent shipwreck, survivors? treasure?) |
| 81-85 | Favorable wind (add 1 mph to travel speed for the day) |
| 86-90 | Water elemental rises from the deep (curious or territorial) |
| 91-95 | Reef or sandbar ahead! Ship runs aground unless spotted (DC 15 Perception) |
| 96-00 | Mysterious island appears (real? mirage? magical? has inhabitants?) |
🚢 Ships and Ownership
Operating a Ship
Crew Costs: Common sailors cost 2 gp per day each. Skilled crew (navigator, first mate, boatswain) cost 4-10 gp per day.
Passenger Fares:
- Hammock in crew quarters: 5 sp per day
- Private cabin (small): 2 gp per day
- Private cabin (luxury): 5-10 gp per day
Damage and Repairs: Ships have a damage threshold equal to half their HP. Damage below this threshold is superficial. Damage above requires repairs.
Repair Costs: 20 gp per hit point repaired. Takes 1 day per 20 HP when in port with shipyard access.
Airborne and Waterborne Vehicles
| Vehicle | Cost | Speed | Crew | Passengers | Cargo | AC | HP | Damage Threshold |
|---|---|---|---|---|---|---|---|---|
| Rowboat | 50 gp | 1.5 mph | 1 | 3 | — | 11 | 50 | — |
| Keelboat | 3,000 gp | 1 mph | 1 | 6 | 0.5 ton | 15 | 100 | 10 |
| Longship | 10,000 gp | 3 mph | 40 | 150 | 10 tons | 15 | 300 | 15 |
| Sailing Ship | 10,000 gp | 2 mph | 20 | 20 | 100 tons | 15 | 300 | 15 |
| Warship | 25,000 gp | 2.5 mph | 60 | 60 | 200 tons | 15 | 500 | 20 |
| Galley | 30,000 gp | 4 mph | 80 | — | 150 tons | 15 | 500 | 20 |
| Airship | 20,000 gp | 8 mph | 10 | 20 | 1 ton | 13 | 300 | — |
- Sailing ship (2 mph) travels 48 miles per day (24 hours)
- Galley (4 mph) travels 96 miles per day
- Crossing a 500-mile sea takes a sailing ship about 10-11 days
Shipwreck Guidelines
Shipwrecks as Plot Devices: Shipwrecks should usually advance the story, not just kill characters randomly. When a ship is destroyed, consider these outcomes:
- Characters wash up on a nearby shore (injured but alive)
- Characters cling to wreckage and drift for 1d4 days before rescue
- A passing ship rescues survivors (friendly? pirates? slavers?)
- Characters find an island or reef to take shelter
- Merfolk or sea creatures rescue characters (for a price?)
🦅 Sky Travel
Flying Mounts
Rest Required: Flying mounts must rest 1 hour for every 3 hours of flight. Maximum 9 hours of flying per day (with 3 hours of rest breaks).
Travel Speed Calculation: A creature's flying speed in feet per round ÷ 10 = mph.
Example: Griffon has 80 ft. flying speed = 8 mph.
Daily Distance: In 9 hours with rest breaks, a griffon (8 mph) covers 72 miles.
Common Flying Mounts
| Mount | Speed | Daily Distance | Notes |
|---|---|---|---|
| Griffon | 8 mph | 72 miles | Requires training, loyal once bonded |
| Hippogriff | 6 mph | 54 miles | Easier to train than griffon |
| Giant Eagle | 8 mph | 72 miles | Intelligent, must be persuaded not tamed |
| Pegasus | 9 mph | 81 miles | Only allows good-aligned riders |
| Wyvern | 8 mph | 72 miles | Dangerous, difficult to control |
| Airship | 8 mph | 192 miles | No rest needed, expensive to operate |
Aerial Encounters
Encounter Guidelines: While flying at altitude, ignore ground-based encounters. Instead consider:
- Aerial predators (rocs, young dragons, wyverns)
- Other flying creatures (griffons, giant eagles, harpies)
- Weather phenomena (thunderstorms, high winds)
- Flying enemy patrols (mounted soldiers, flying monsters)
- Airships or sky cities (if your setting has them)
Flying Weather Hazards
| Hazard | Effect |
|---|---|
| Strong Winds | Mount must make DC 10 Strength save or be blown 1d4 × 10 feet off course |
| Thunderstorm | Disadvantage on Perception checks, lightning strikes (DC 15 Dex save, 2d10 lightning damage) |
| Hail | Mount and rider take 1d4 bludgeoning damage each hour |
| Fog/Clouds | Visibility drops to 30 feet, easy to get lost |
| Extreme Cold (high altitude) | DC 10 Con save each hour or gain 1 level of exhaustion |