When Dungeons Arise: Seven Seas

Overview

When Dungeons Arise: Seven Seas is an expansion mod for When Dungeons Arise that brings maritime exploration to the forefront. While the base mod focuses on massive land-based structures, Seven Seas adds five distinct ocean vessels that generate naturally across all Ocean biomes. Each ship is built entirely from vanilla blocks, meaning the mod introduces no new items or blocks to your inventory. Instead, the challenge comes from heavily armed hostile mobs guarding valuable loot scattered throughout multiple decks.

The five structures range from the compact Small Yacht and Corsair Corvette to the sprawling Victory Frigate, which features 11 separate mob spawner zones. Every ship contains Barrels with basic supplies, normal Chests with mid-tier gear and enchanted equipment, and treasure Chests loaded with Diamonds, Emeralds, and enchanted Diamond armor. Some ships also feature supply caches filled with food. The mod uses the jigsaw structure system with a spacing of 68 chunks and a minimum separation of 60 chunks, so you will not find ships on every horizon, but patient ocean explorers will be well rewarded.

Prerequisites

Seven Seas is a standalone expansion, but it is designed as a companion to When Dungeons Arise. You do not need the base mod installed for Seven Seas to function; however, having both installed fills your world with structures on both land and sea. The mod requires Forge (version 43+) and supports Minecraft versions 1.20 through 1.20.x. No other dependencies are needed.

The Five Ships

Seven Seas adds five distinct ship structures, each with equal spawn weight in the world generation pool. Every ship generates in Ocean biomes using Minecraft's jigsaw structure system. While the loot tables share a common foundation, the ships differ dramatically in size, mob density, and layout complexity. Below is a detailed breakdown of each vessel.

Small Yacht

The Small Yacht is the most compact ship in the mod, featuring 4 spawner zones. It sits at a start height of -3, meaning it partially submerges in the water for a realistic appearance. Despite its modest size, the Yacht still contains normal and treasure Chests with enchanted gear and precious materials. This is a good entry-level ship for players who want to test their combat readiness before tackling larger vessels.

Corsair Corvette

The Corsair Corvette is an infested vessel crawling with hostile mobs. With 5 spawner zones and a start height of -2, it rides lower in the water than most ships. The Corvette is themed around decay and infestation; expect to find Silverfish Spawners, Cobwebs, Skeleton Skulls, and Bones throughout the wreckage. The crew has long since perished, but the loot they left behind includes enchanted Iron and Chainmail equipment, Diamonds, and Emeralds.

Pirate Junk

The Pirate Junk is a hostile pirate vessel featuring 6 spawner zones. It generates at sea level (start height 0) and features ladders for climbing aboard. The crew here is distinctly pirate-themed, with Pillager and Vindicator mobs wearing custom player heads and wielding specialized weapons. Some pirates carry Crossbows loaded with Firework Rockets, a devastating ranged attack you will rarely encounter elsewhere. Below deck, you will find prison cells holding captive Villagers, supply rooms stocked with food, and treasure rooms. The Pirate Junk uniquely features supply Chests packed with food items like Beef, Bread, Baked Potatoes, Pumpkin Pie, Honeycomb, Honey Bottles, and even Golden Apples and Golden Carrots.

Unicorn Galleon

The Unicorn Galleon is a shipwrecked vessel, partially grounded on terrain at a start height of -4, the deepest submersion of any ship. With 6 spawner zones, this is a mid-to-large structure. The wreck tells a story: crew members can be found riding on Bats, carrying Bows, and some even hold enchanted Flint and Steel. Other zombified crew members wield dual Iron Swords. The Galleon features multiple below-deck levels, with Spawners on every floor. It includes both supply and treasure loot, meaning you will find both food stores and high-value enchanted gear. The shipwrecked aesthetic means you will often find it lodged against icebergs or terrain features, making for a dramatic visual.

Victory Frigate

The Victory Frigate is the largest and most dangerous ship in Seven Seas, featuring a staggering 11 spawner zones. It generates at a start height of -1, sitting proudly above the waterline like a proper warship. The Frigate has both upper and lower normal loot tables, supply caches, and its treasure Chests contain the best loot in the entire mod: enchanted Diamond Helmets, Diamond Chestplates, Diamond Leggings, Diamond Boots (enchanted at levels 5 to 30 with treasure enchantments), and Enchanted Books at level 30. Clearing this ship is a serious undertaking that requires careful planning, good equipment, and patience. Work through it systematically, deck by deck, or you risk being swarmed from multiple directions.

Loot and Rewards

Every ship uses a tiered loot system with distinct container types. Understanding what each container offers helps you prioritize your search and decide which ships are worth the risk.

Barrels (Basic Supplies)

Barrels are found on all five ships and contain the same pool of practical supplies: Iron Ingots (2-4), Dark Oak Logs (2-4), Sticks (2-4), String (2-3), Charcoal (2-3), and Gunpowder (8-12). You may also find utility items like Flint and Steel, Buckets, Shears, Bowls, or Salmon Buckets. These are not exciting finds, but the Gunpowder in particular is valuable for crafting TNT or Firework Rockets.

Normal Chests (Mid-Tier)

Normal Chests offer a solid step up from Barrels. Each one can contain Enchanted Books with random enchantments, Gold Nuggets (4-12), Diamonds (1-2), and Emeralds (4-16). The real prizes are the 1-2 pieces of randomly enchanted armor and weapons (enchantment levels 15-25), including Iron Swords, Chainmail Helmets, Chainmail Chestplates, Iron Leggings, and Chainmail Boots. You will also frequently find Bones, Skeleton Skulls, Cobwebs, Books (1-16), and more Gunpowder (4-32).

Supply Chests (Food Stores)

Supply Chests appear on the Pirate Junk, Unicorn Galleon, and Victory Frigate. They roll 4 items per chest from a generous food pool: Beef (8-12), Bread (1-7), Baked Potatoes (4-8), Melon Slices (8-12), Pumpkin Pie (4-5), various Fish (2-16), Mushroom Stew (2-3), Honeycomb (4-16), and Honey Bottles (3-6). Rarer finds include Chorus Fruit, Wet Sponges, Milk Buckets (1-3), Golden Apples, and Golden Carrots. These supply rooms can restock your food entirely for extended ocean voyages.

Treasure Chests (High-Tier)

Treasure Chests are the ultimate reward and differ significantly between ship tiers. On the Small Yacht, Corsair Corvette, and their counterparts, treasure Chests contain enchanted Iron armor and weapons (levels 15-25), Iron Ingots (12-24), Gold Ingots (6-12), Diamonds (2-5), and Emeralds (4-16). The Pirate Junk and Unicorn Galleon step things up with Diamond Helmets and Diamond Boots enchanted at levels 5-30, plus level 30 Enchanted Books.

The Victory Frigate has the best treasure in the mod. Its treasure Chests can drop a full set of enchanted Diamond armor: Diamond Helmet, Diamond Chestplate (enchanted 15-30), Diamond Leggings, and Diamond Boots, all with treasure-level enchantments. This means you can potentially find Enchanted Books and armor with enchantments like Mending, Frost Walker, or Soul Speed that normally only appear through treasure enchanting. Combined with Diamonds (3-6) and Emeralds (4-12), a single Victory Frigate run can outfit you for the endgame.

Hostile Mobs

The mobs aboard Seven Seas ships are not standard vanilla enemies. They are custom-equipped variants with boosted armor values, elevated health, and specialized gear themed to each ship. The mod uses vanilla mob types (Skeletons, Zombies, Pillagers, Vindicators, Illusioners, and Silverfish) but customizes them through NBT data to create far more dangerous encounters.

Corsair Corvette Mobs

The Corsair Corvette is themed around infestation and undeath. Skeletons aboard this ship have significantly elevated health (16-34 HP compared to the vanilla 20 HP) and wear hidden armor providing up to 17 armor points. Some Skeletons carry Creepers as passengers on their heads, creating a uniquely dangerous combination where killing the Skeleton releases a Creeper at close range. Silverfish Spawners add to the chaos, swarming you in tight corridors below deck.

Pirate Junk Mobs

The Pirate Junk features the most varied mob roster. Illusioners spawn with 32 HP and create mirror images of themselves, making them extremely disorienting in combat. Pillager pirates wear custom player heads and carry Crossbows loaded with Firework Rockets, dealing explosive splash damage that is difficult to avoid in the ship's narrow corridors. Vindicators with 14 armor points serve as the heavy hitters, dealing devastating melee damage with their Axes. This combination of ranged explosive damage and high-damage melee attacks makes the Pirate Junk one of the most dangerous structures despite its mid-range size.

Unicorn Galleon Mobs

The Unicorn Galleon's zombified crew tells the story of a doomed voyage. Zombies here have 16 armor points and some wield dual Iron Swords. Uniquely, some crew members ride Bats, giving them aerial mobility that makes them harder to hit and allowing them to swoop down from unexpected angles. Others carry Parrots as passengers on their shoulders for a thematic touch. Some crew members hold enchanted Flint and Steel, though whether they can use it depends on the specific mob AI. With 6 spawner zones spread across multiple below-deck levels, clearing the Galleon requires fighting through layer after layer of undead sailors.

Exploration Strategy

Approaching Seven Seas ships requires a different mindset than raiding land-based dungeons. You are fighting on water with limited escape routes, tight corridors, and mobs that can knock you overboard. Start with the smaller ships (Small Yacht, Corsair Corvette) to get comfortable with the combat style, then work your way up to the Pirate Junk and Unicorn Galleon. Save the Victory Frigate for when you have Diamond armor and enchanted weapons.

When boarding a ship, always approach from the side with ladders or the lowest deck access point. Fight your way upward first to clear the open decks where you have room to maneuver, then descend into the lower decks. Bring Torches or other light sources to prevent additional mob spawns in dark areas after you clear the Spawners. A good practice is to place Torches on every Spawner you break as a visual marker that you have already cleared that area.

For the Victory Frigate specifically, consider bringing blocks to seal off corridors as you clear them section by section. With 11 spawner zones, trying to rush through will result in mobs flooding in from areas you have not cleared yet. A methodical, room-by-room approach is the safest path to claiming the Frigate's exceptional Diamond loot.

Using Ships as Bases

Since all ships are built entirely from vanilla blocks, they are fully customizable after clearing. The Pirate Junk and Victory Frigate make particularly good ocean bases due to their size and multiple interior rooms. After removing all Spawners and lighting up dark areas, you have a pre-built structure with storage rooms, sleeping quarters, and sometimes even pre-placed Crafting Tables and Furnaces. The ships are also highly flammable since they are primarily built from wood, so be careful with Lava and Fire near your new floating home.

World Generation Details

All five ships use the minecraft:jigsaw structure type and share the same structure set with equal weight distribution (weight 1 each). The placement uses random spread with a spacing of 68 chunks and a minimum separation of 60 chunks, with a salt value of 98123789. This means structures are fairly rare, averaging roughly one ship every 68 chunks in any direction, with at least 60 chunks between any two ships.

Each ship is assigned to the #minecraft:is_ocean biome tag, meaning they can generate in any Ocean variant: regular Ocean, Deep Ocean, Warm Ocean, Lukewarm Ocean, Cold Ocean, Frozen Ocean, and their deep variants. The Unicorn Galleon, with its -4 start height, tends to appear more submerged and is often found wrecked against terrain, while the Pirate Junk at height 0 sits right at the waterline. The Victory Frigate at -1 maintains an imposing above-water silhouette.