d1000 Sea encounter table

Nature
 001-025 Hard Rain
 026-051 Mist
 052-072 Reef
 073-083 Eddy
 084-094 Ice Floes
 095-098 Sandy Islet
   099   Tornado

Litter
 100-119 Empty Crates, Empty Barrels
 120-129 Harmless Algal Ooze
 130-139 Giant Amoeba
 140-149 Corrosive Ooze
 150-159 Flytrap Ooze
 160-169 Inert Pulverized Animal Sludge
 170-179 Ooze (Mimic)

 180-199 Abandoned Ship 
  d20:
   01-10 Stripped and Looted
   11-18 Hastily-abandoned (with some cargo)
   19 Infested (overland smart-monster rand-enc + rats + slimes + pests)
   20 With stranded (dead?) crew

  d20:
   01-09 single-person boat
   10-13 longship
   14-15 light ship ("schooner, ketch")
   16-17 light galley
     18  large galley
     19  large ship ("hagboat, barque")
     20  war galley

  d20:
   01-06 front half only
   07-11 back half only
   12-19 broken in two sinking halves
    20   whole

Manned Ships : Crew Type
 ::
 Possibly single-person
  d8:
   1 single boat with lone pilot
   2 single boat with crew of 1-6
   3-5 1-6 1-ton capacity boats with a crew of 1-6
   6 sailing ship with crew of 30
   7 rowboat with crew of 90
   8 fleet of 1d8 ships
 ::
  200-299 Fisher
  300-335 Salvager
  336-345 Deserter
  346-355 Mutineer
  356-365 (Probably Heretic) Barbarian
  366-376 Hag cult
  377-380 Druid
  381-383 Elf
  384-394 Cursed Man
  395-397 Monster Hunter
    398   Alchemist 
    399   Mage

 ::
 1-8 Ships (each at least 80 crew)
 ::
   400-419 Commodity Trader
   420-439 Livestock Trader
   440-459 Victualer
   460-479 Whaler
   480-481 Lumberjack
   482-483 Miner
   484-485 Slaver
   486-487 Viking
   488-489 Pirate
     490   Rich Pervert
     491   Performer
     492   Monk-Errant
     493   Gnome
     494   Grevan
     495   Flayer
     496   Caveman
     497   Snow Orc
     498   Gnole
     499   Ratmen

Swimmers
  500-531 90lb+ Fishes (tunas, halibuts, cods)
  532-563 Sharks
  564-595 Dolphins
  596-619 Seals
  620-642 Walruses
  643-659 Orca
  660-669 Water-striding spider
  670-679 Leech men
  680-689 Mermen
  690-699 Deep One

Lone Swimmers
 700-709 Giant Squid
 710-719 Giant Octopus
 720-729 Sea Serpent
 730-739 Giant Carp
 740-749 Plesiosaur
 750-759 Ocean Giant
 760-769 Merrow
 770-779 Mega crocodile
 780-789 Waterworm
 790-799 Sea Hydra

Fliers 
 800-809 Seagull
 810-819 Mallard
 820-829 Crow
 830-839 Pigeon
 840-849 Vulture
 850-859 Osprey
 860-869 Harpy
 870-879 Pterodactyl
 880-889 Hieracosphinx
 890-899 Griffon

Undead (reroll):
 900-949 skeletal
 950-989 zombie
 990-995 bog-mummied (animals zombie)
 996-999 draugar     (animals skeletal)



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Notes
 "what if i roll something nonsensical like bog-mummied mist" i don't know do your best

 The book "the minrothad guilds" has a great random commodities table if you need one in a pinch
 Pathfinder (gmg?) also has a awesome trade goods table: https://www.d20pfsrd.com/equipment/goods-and-services/furniture-trade-goods-vehicles/

 Besides the random encounters, try not to run out of food and try not to drown