There are shiprules for Shadowdark in Cursed Scroll 3 and the Player’s Guide to the Western Reaches, but they are more suited for a viking campaign than explorers, whalers and pirates on the high seas. So I came up with my own rules for 17th century sailing vessels. (most pirate settings go for the 18th century, but I wanted to go slightly earlier, when ships and crews were smaller.)

They are compatible with the other rules from Cursed Scroll or Western Reaches however, like Warbands for mass combat, Bastions or Siege Weapons.

Also Equipment and Spells for diving and under-water-adventures and some ocean critters. 

Combat in Water

When swimming or diving, you move with half your normal speed, all melee attacks are made with disadvantage, ranged attacks are not possible. All weapons that are not thrusting weapons (like daggers, spears, straight swords) only do half their normal DMG.  

A character can hold their breath for a number of rounds equal to their CON mod (min. 1). Then they start drowning, DC 12 CON check or take 1d6 dmg until they can breathe again. 

New Items

Sailing and Fishing Equipment

New Weapons

Rope (R): A rope can be fastened to the weapon. If it inflicts any damage, it sticks in the target. It can be pulled out with a DC 15 STR check, inflicting their damage again when pulled out.

Underwater (UW). Can be used underwater at range and without disadvantage. 

Trident. A tri-prong spear for fishing

Harpoongun. A spring-loaded or pneumatic gun that can shoot harpoons underwater

Artificer Items

These rare items are so advanced in technology that they are indistinguishable from magic. 1 equipment slot if not otherwise stated. 

Aqualung

Pressure regulators, hoses and mouth piece.Uses pressure bottles with compressed air.

Benefit. Lets you breathe air from pressure bottles. Price. 1000g, 

Bracelet Watch

A mechanical wonder, its mechanism housed in a robust, watertight brass bracelet. 

Benefit. Let’ you keep track of time, tiny itemPrice. 500g 

Pressure Bottles

Can be used with a Full Diving Suit or Aqualung.

Benefit. supply 1 hour of air each. 

Price. 100g

Pressure Gauge

An instrument that can measure water pressure in a sturdy brass housing.

Benefit. let’s you know how deep you are. tiny item 

Price. 150g

Light Sources

Diving Lamp

A lamp that holds diving light, a mixture of sperm oil and pressurized oxygen. 

Benefit. Lights for 1 hour like a lantern with 1 supply of Diving Light.Price. 250 gp, 1 supply of Diving Light 10 gp

Magnesium Torch

An alchemical torch that burns even under water in a bright light, shining in up to a double near distance. 

Benefit. Produces light like a lanternPrice. 25g

Lamp Fish / Fish Lamp

A fish that glows in colorful bioluminescence when no other light sources are present. Bred over generations to be as bright as a torch. 

Benefit. An underwater lightsource

Curse. The light attracts zooplankton that the fish eats. Roll a d6 each hour, on a 1 the fish had its fill and stops glowing for a day. Price. 150 gp 

Sylph Lamp

In a lamp of transparent and black chitin a captured Sylph sulks and hopes for rescue.

Benefit. It sheds a pale light as bright as a torch, without heat or the need for air or oil. 

Curse. A Sylph held against her will brings nightmares and misfortune. Price. The price is not paid in coin. 

Special Lamp Oil

Spells

There are no waterbreathing spells, as I think that makes diving too easy. Note that the shapechange spells don’t give waterbreathing either. Even a sperm whale has to hold its breath. 

Sealform

Tier 1

Duration. 10 rounds 

Range. Self

You and your gear turn into a seal with the below stats for the spell's duration.

You cannot cast spells while under the effect of this spell.

You retain your INT, WIS, and CHA stats.

If you fall to 0 HP while transformed, you revert back to your original form at 1 HP.  

AC 12, HP 11, ATK bite +2 (1d6), MV double near (swim), 

S +2, D+2, C +2

Dolphinshape

Tier 2

Duration. 3 hours

Range. Self

You and your gear turn into a dolphin with the below stats for the spell's duration.

You cannot cast spells while under the effect of this spell.

You retain your INT, WIS, and CHA stats.

If you fall to 0 HP while transformed, you revert back to your original form at 1 HP.  

AC 12, HP 21, ATK bite +4 (1d8), MV double near (swim), 

S +3, D+2, C +3

Pod Hunter. Deals +2 damage while an ally is close

Orcamorph

Tier 3

Duration. 6 hours

Range. Self

You and your gear turn into an orca with the below stats for the spell's duration.

You cannot cast spells while under the effect of this spell.

You retain your INT, WIS, and CHA stats.

If you fall to 0 HP while transformed, you revert back to your original at 1 HP.  

AC 12, HP 39, ATK 2 bite +5 (1d10), MV double near (swim), 

S +4, D+0, C +4

Pod Hunter. Deals +2 damage while an ally is close

Sperm Whale Gestalt   

Tier 4

Duration. 1 day

Range. Self

You and your gear turn into a sperm whale with the below stats for the spell's duration.

You cannot cast spells while under the effect of this spell.

You retain your INT, WIS, and CHA stats.

If you fall to 0 HP while transformed, you revert back to your original form at 1 HP.  

AC 12, HP 72, ATK 2 bite +10 (1d20), or crush +0 (5d20), MV double near (swim), 

S +6, D-1, C +6

Sonar Blast. Creatures a cone in near must pass DC14 CON or become stunned for 1d4 rounds.

Swallow. If both attacks hit the same target, the target is swallowed. 

Total darkness inside and 1d12 damage per round. Whale regurgitates all swallowed if 

dealt at least 20 damage to the inside of its stomach.

Waterkinesis 

Tier 1

Duration. Focus

Range. Near 

Let's manipulate up to 50 pounds of water up to a near distance. Your spellcasting attribute is considered your S and D stat for using this water.

Freeze 

Tier 3

Duration. Instant

Range. Near 

Freezes a volume of water up to a near-sized cube. Creatures caught in the ice take 2d8 dmg. STR 16 check to break free.    

Waterblade 

Tier 4

Duration. Instant

Range. Near 

You manipulate close water to shoot as a super-high-pressure stream that can cut through steel. The spell does 5d8 damage in a near-sized cone. 

Ship Combat

Ships spot each other at long distances unless special circumstances like darkness, fog or island-cover prevent vision. If you want to fight, the other ship can try to run. The faster ship will always outrun or chase down the slower ship. In a draw, the captains make an opposed CHA check (command) to determine who’s faster. When ships get close enough to each other to exchange fire, Ship Combat begins and the captains roll Initiative. 

Initiative

The captains make a CHA check (command). Ships and crew take their turns from highest to lowest result. 

Ship Actions

The captain decides which action the ship takes. There are three common actions. Ranged Attacks, Running and Boarding. 

Ranged Attacks

Exchange of ranged attacks. You can fire ship weapons on one broadside and additional small arms. Hitting a ship is an attack against the ship’s AC, hitting a single creature on deck is an attack against that creature’s AC.

Running

The faster ship can run from combat. The other ship gets 1d4 rounds of free, ranged attacks before the fleeing ship gets out of range. You cannot flee once boarded. 

Boarding

The faster ship can decide to board the other vessel. There will be one more round of ranged attacks at far range, one more at near range, as the ship gets into position, then the ships can be pulled together with grappling hooks and normal combat between the crews of the ships starts.

Explosions might hit your own allies if you fire at a ship your crew is boarding, fires might spread from ship to ship.  

Crew Hits

This can be used instead of the Warband rules from Western Reaches. 

Crew on deck can be targeted normally. Area damage, like, for example weapons with Blast (B), some spells, or fire, deals damage to both ship and crew and cannot target individuals. Assume that 1 crew member is killed for each 3 area damage inflicted on the ship. PCs are not normally hit and killed by Crew Hits. (we don’t want to calculate a %roll each time, and that would be boring)The players decide which crew-members are killed. They can also decide to take 1d6 DMG on their character to save a crew-member.  

Ship Damage

Ships take damage like characters. If they are reduced below half their max HP their speed is halved. If they are reduced below their minimum crew their speed is also halved. If the speed is halved twice, it falls to 0.

Fire

A ship that takes 4 fire damage from one attack starts to burn. It gets 1 Burning Condition. A ship can take several Burning Conditions from one attack if it does a multiple of 4 fire damage. (8, 12, 16. . . ) At the start of each round, the ship takes d4 damage for each Burning Condition. A 4 the damage roll will add another Burning Condition as the fire spreads (also to a boarding ship). 

1 crew member can remove 1 burn condition with their action per round by extinguishing fires. 

Flooding

A ship that takes 4 damage under its waterline from one attack starts to flood. It gets 1 Flooding Condition. A ship can take several Flooding Conditions from one attack if it does a multiple of 4 damage. (8, 12, 16. . . ) At the start of each round, the ship takes d4 damage for each Flooding Condition. 

1 crew member can remove 1 Flooding Condition with their action per round with the use of Carpenter Tools and 1 Carpenter Supplies by patching up holes. 

Repairs

A crew member with carpenter tools can use its action to patch up the ship, using up 1 carpenter supplies, restoring 1 HP. These Quick Repairs must be reworked out of combat, or they will break when sailing at more than ½ speed. Normal, permanent repairs take 1 day instead of 1 round. 

Sinking

If a ship is reduced to 0 HP is beyond repair, it starts to sink. It takes 1D4 turns to sink. Time to get into the boats, if you have any. 

A boat sinks in 1D4 rounds.

Boats and Ships

Name. What the type of ship is called

Type. If it is a boat or ship. 

Cost. The cost of the ship in gold pieces. 

AC,HP. Just like a character’s or monster's armor class and hitpoints. 

Cargo. Cargo capacity in equipment slots. Carrying a character and their equipment takes up 10 slots of cargo. Crew. The minimum crew is needed for normal sailing and does not count as cargo. Extra crew is good to have as reserve or to man weapons. 1 extra crew member counts as 10 slots of cargo.Speed. Number of 6-mile hexes the ship can travel in 8 hours. In combat, ships can move a number of feet equal to their speed x 5 feet.Properties.  Oars. Can move with half their speed in any weather. Their combat speed is doubled.

Boat. A small boat with oars Shallop. A long boat with oars and sailBuss. A small ship, common fishing vesselPinnace. A small and fast ship, favored by pirates and navies Barque. A medium sized ship used by whalers, traders, navies and pirates alikeGalley. A ship of war with sails and many oars, prized in calm seas for its speedFluyt. A large, efficient ship with a pear-shaped hull, favored by far-traders. Frigate. A large and fast ship, used to hunt pirates and raid commerce. Galleon. A huge ship, used as ships of war or armed treasure ships. 

Ship Equipment

Stuff you might add as an upgrade to your ship.

Weight. You can install equipment on ships, lowering the cargo capacity by the weight.

Ship weapons

These heavy weapons can be mounted on ships, castles, or used as field artillery; they must be manned by 1 crew per 10 slots of weight that handles loading, shooting and ammunition supply. For every crew fewer than that, loading takes an additional round.  

Weight. You can install guns on ships, lowering the cargo capacity by the weight. 

Blast (B). The weapon hits everything within near of the impact. 

Exploding (E). If you roll the maximum number on a damage die, roll an additional damage die. That one can also explode.  

Slow Loading (SL). It takes an entire round to load the weapon

Rope (R). A rope can be fastened to the weapon. If the weapon inflicts any damage, it sticks in the target. It can be pulled out with a DC 15 STR check, inflicting their damage again when pulled out.

Ram (RA). Ram a ship as part of a boarding action, inflicting the ramming damage,  

Ammo

Cannons, Sakers and Swivel Guns can be loaded with a variety of ammunition. All ammo costs 1 gp and takes up 2 equipment slots per shot.

Ocean Critters

Dolphin

Bright sleek sea dwelling mammals that hunt in packs.  

AC 12, HP 21, ATK bite +4 (1d8), MV double near (swim), 

S +3, D+3, C +3, I 0, W +1, Ch +1, AL N

LV 4

Pack Hunter. Deals +1 damage while an ally is close

Great White Shark

A huge, pale apex-predator that can taste blood in the water. 

AC 12, HP 27, ATK 3 bite +5 (1d10), MV double near (swim), 

S +4, D+0, C +3, I -3, W +1, Ch -3, AL N

LV 6

Seal

Dogs of the sea, that can be found in huge herds on sand banks. 

AC 12, HP 11, ATK bite +2 (1d6), MV double near (swim), 

S +2, D+2, C +2, I -2, W +1, Ch -1, AL N

LV 2

2 bite +5 (1d10)

Sperm Whale

Huge whales with dome shaped heads and a long jaw full of hungry teeth. 

AC 12, HP 72, ATK 2 bite +10 (1d20), or crush +0 (5d20), MV double near (swim), 

S +6, D-1, C +6, I -1, W +1, Ch -2, AL N

LV 12

Sonar Blast. Creatures a cone in near must pass DC14 CON or become stunned for 1d4 rounds.

Swallow. If both bite attacks hit the same target, the target is swallowed. 

Total darkness inside and 1d12 damage per round. Whale regurgitates all swallowed if 

dealt at least 30 damage to the inside of its stomach.