Uploaded April 2026 | Updated September 2026, 2 weeks ago
Most GMs treat an underwater dungeon like a regular dungeon with a blue filter. That’s a mistake. If you want that classic B/X tension, you must embrace the hostile nature of the environment. Light becomes a timer, and air becomes a liability.
In this talk, we break down specific OSR procedures for running an 'Abyssal' sea-crawl:
The Jellyfish Lantern: Why mundane light fails and why 'Glow Stones' kill tension.
The Oxygen Tax: Three distinct (and hazardous) ways to handle breathing without using high-level magic.
Combat and Buoyancy: Why chainmail is a death trap, and how physics changes the combat encounter.
Designing Atlantis: Why stairs don't exist in aquatic civilizations.
Don’t just run Atlantis; make your players survive it.
The Tavern Rules: We’re here for B/X and OSR gaming. I use AI as a tool to help organize and format my notes, but every ruling and opinion is 100% Tenkar. Keep it civil, keep it old-school, or the bouncer will show you the door.
Become a Minion and Join The Tavern's Community to get access to perks (including more FREE OSR material):
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Join The Tavern’s Discord Server (It's Free):
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Buy me a Beer!
ko-fi.com/tenkar
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The Tavern uses Restream for its livestreams and its long-form videos. You can too! restream.io/join/g5Qpgr
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Master Minion: terrytaylor113, blahlbinoa, DeanSals1, dmakron, agilemonk6305, matthewsherman1183, DanTesch, douglaspearson9552, HalflingTorchbearer, murseoftheyear , tireddaddyof4267, yardofguiness
Super Minion: Indigo Ro, DM Raptor, SinnerElla, Ryan Nilsson, Erik Wahlberg, Donalds Angry, COS Crafts, maxnomicon, Midnight Green, Rich3rd, Gladstone Pinheiro, Cecilia Souza, Joe Stone, boss bully boy, Marcelo Correia, Richard Hooper, ᄃΉΣMIᄃΛᄂᄃӨᄃӨПЦƬ, T Flo_Ijimisan, LawDawg, Unscripted ＆ Unchained, JimothyTimothy, Eupolemos, Jay, Martin Penny, im cafferty, Chris Burkhart, Douglas Pearson, Curt Gould, Matthew Sherman
Minions: Andrew Lowe_Dave Canela_Mark the Shark_Dungeon of Terra_Lazy Titan_SWORDS‘N’STONES_gregor1865_Mazechess_Justin Smith_David Williams_Anthony Holdren_Dungeon Bloom_V_Jared Bajkowski_Wibstozbin_Michael Mullen_Greg Arnold_dre g_orogustus_Michael Gorsuch_Scott Roberts_Mac_Bryan!_ Mike Burke_Jeremy Baisch_Jim_Ron The Sage_nunya binnaz_Dennis Schwardt_DocFlamingo_Shawn Murphy_Dduhon92_drwatkins68_drwatkins68_Richard Smith_Thierry Chauvin_Stefan Nussbaum_Whit Whitman_jason ferrell_Don Semora_gary oliver_Joethelawyer_ Minions: Stephane Lefort_Martin McKendry_Alvar Berget_Diogo Pires_Rubens Barrichello_Christopher Colla_The Wandering Zhoop_Joseph Pilkus_vinimagus_Chris G_Tim Shorts_Dan Tesch_Ryan Nicolai_Keith Hershey Jr_渋禽_The Saged Wizard_Climbing That Mountain_Brass Monkey_m w_Ordo Hereticus_TheGlennsof_Robert Santen_The ASL Prof_D＆D Old Guard_Michael Søgren Jensen_Conch_My Ear Trumpet_Eric Jeppesen_Headless Bourgeoisie_Jack Neller_DM Angelo_Stash_Itay Miara_vZwicky_Terry Broadbent_Max Rollax_Électrique_Chad Dickhaut_Rob Conley_1776sunshine_Gustavo Campos_KVNDV1_S Lewis_FifthAvenger_Ian White_Greyhawk Grognard_Gábor Szeberényi_Anthony Corcoran_Dave Marmachand_Chthonic Musings_Bruce Lombardo_Vanishing Tower_srahla_Fat Dragon_Paul Cattrone_Hommlet Bound_Jefferson Starship_Sovereign Wolf_@DM Knucklebones_Roger Rebisz_James Spahn_Esteban Vazquez_Flint Fireforge_EruditeDM_Thiatas Ashadarawesh_Steve Roy_Dethangels Shadow_Matthew Archibald_WTG_unclebrat_Andrew Marrington_MikerDude_Tom K_Glynn Seal
#OSR #OldSchoolRenaissance #BX #DandD #BasicDandD #TTRPG #DungeonMasterTips #UnderwaterAdventure #DungeonDesign #RetroRoleplaying #TenkarsTavern #SeaCrawl
Most GMs treat an underwater dungeon like a regular dungeon with a blue filter. That’s a mistake. If you want that classic B/X tension, you must embrace the hostile nature of the environment. Light becomes a timer, and air becomes a liability.
In this talk, we break down specific OSR procedures for running an 'Abyssal' sea-crawl:
The Jellyfish Lantern: Why mundane light fails and why 'Glow Stones' kill tension.
The Oxygen Tax: Three distinct (and hazardous) ways to handle breathing without using high-level magic.
Combat and Buoyancy: Why chainmail is a death trap, and how physics changes the combat encounter.
Designing Atlantis: Why stairs don't exist in aquatic civilizations.
Don’t just run Atlantis; make your players survive it.
The Tavern Rules: We’re here for B/X and OSR gaming. I use AI as a tool to help organize and format my notes, but every ruling and opinion is 100% Tenkar. Keep it civil, keep it old-school, or the bouncer will show you the door.
Become a Minion and Join The Tavern's Community to get access to perks (including more FREE OSR material):
youtube.com/channel/UCIdpAASpAI7vu-bZx6pP_mQ/join
Join The Tavern’s Discord Server (It's Free):
discord.gg/fReGmuD
Buy me a Beer!
ko-fi.com/tenkar
The Tavern uses affiliate links:
Humble Bundle: humblebundleinc.sjv.io/da4WJ2
The Tavern’s Amazon Storefront: amzn.to/41Jm0oG
DriveThruRPG: drivethrurpg.com/en/?affiliate_id=1446
Fantasy Grounds VTT: affiliates.fantasygrounds.com/388855/15958
The Tavern uses Restream for its livestreams and its long-form videos. You can too! restream.io/join/g5Qpgr
The Tavern uses ClipGOAT to create its shorts. You can use it too!
clipgoat.com/?ref=erik
The Tavern also uses VidIQ: vidiq.com/TenkarsTavern
Master Minion: terrytaylor113, blahlbinoa, DeanSals1, dmakron, agilemonk6305, matthewsherman1183, DanTesch, douglaspearson9552, HalflingTorchbearer, murseoftheyear , tireddaddyof4267, yardofguiness
Super Minion: Indigo Ro, DM Raptor, SinnerElla, Ryan Nilsson, Erik Wahlberg, Donalds Angry, COS Crafts, maxnomicon, Midnight Green, Rich3rd, Gladstone Pinheiro, Cecilia Souza, Joe Stone, boss bully boy, Marcelo Correia, Richard Hooper, ᄃΉΣMIᄃΛᄂᄃӨᄃӨПЦƬ, T Flo_Ijimisan, LawDawg, Unscripted ＆ Unchained, JimothyTimothy, Eupolemos, Jay, Martin Penny, im cafferty, Chris Burkhart, Douglas Pearson, Curt Gould, Matthew Sherman
Minions: Andrew Lowe_Dave Canela_Mark the Shark_Dungeon of Terra_Lazy Titan_SWORDS‘N’STONES_gregor1865_Mazechess_Justin Smith_David Williams_Anthony Holdren_Dungeon Bloom_V_Jared Bajkowski_Wibstozbin_Michael Mullen_Greg Arnold_dre g_orogustus_Michael Gorsuch_Scott Roberts_Mac_Bryan!_ Mike Burke_Jeremy Baisch_Jim_Ron The Sage_nunya binnaz_Dennis Schwardt_DocFlamingo_Shawn Murphy_Dduhon92_drwatkins68_drwatkins68_Richard Smith_Thierry Chauvin_Stefan Nussbaum_Whit Whitman_jason ferrell_Don Semora_gary oliver_Joethelawyer_ Minions: Stephane Lefort_Martin McKendry_Alvar Berget_Diogo Pires_Rubens Barrichello_Christopher Colla_The Wandering Zhoop_Joseph Pilkus_vinimagus_Chris G_Tim Shorts_Dan Tesch_Ryan Nicolai_Keith Hershey Jr_渋禽_The Saged Wizard_Climbing That Mountain_Brass Monkey_m w_Ordo Hereticus_TheGlennsof_Robert Santen_The ASL Prof_D＆D Old Guard_Michael Søgren Jensen_Conch_My Ear Trumpet_Eric Jeppesen_Headless Bourgeoisie_Jack Neller_DM Angelo_Stash_Itay Miara_vZwicky_Terry Broadbent_Max Rollax_Électrique_Chad Dickhaut_Rob Conley_1776sunshine_Gustavo Campos_KVNDV1_S Lewis_FifthAvenger_Ian White_Greyhawk Grognard_Gábor Szeberényi_Anthony Corcoran_Dave Marmachand_Chthonic Musings_Bruce Lombardo_Vanishing Tower_srahla_Fat Dragon_Paul Cattrone_Hommlet Bound_Jefferson Starship_Sovereign Wolf_@DM Knucklebones_Roger Rebisz_James Spahn_Esteban Vazquez_Flint Fireforge_EruditeDM_Thiatas Ashadarawesh_Steve Roy_Dethangels Shadow_Matthew Archibald_WTG_unclebrat_Andrew Marrington_MikerDude_Tom K_Glynn Seal
#OSR #OldSchoolRenaissance #BX #DandD #BasicDandD #TTRPG #DungeonMasterTips #UnderwaterAdventure #DungeonDesign #RetroRoleplaying #TenkarsTavern #SeaCrawl
