Tuesday, October 6, 2015

Random Ocean and Island Terrain Tables

Earlier today there was a request on G+ for ocean and water terrain tables.  I don't know of any and the lack of them dates back to the 1e DMG, which stated that the DM must draw them in by hand.  Chivalry & Sorcery has a similar statement.  

I think the biggest reason no one published them is that you can't reliably randomly generate a meaningful coast line, there's no guarantee in these tables that your coast won't encircle your map or have a strange gap in it.  I've tried to control for that by assuming that you map the coast while you sail along it, but your result WILL vary.

If you have any suggestion for improvement leave a note, drop me a line or put a message in a bottle and heave it overboard.  Of course, I'm up near the falls of the Mississippi, so the last probably won't reach me.

Ocean Terrain Generator

RollDeep WaterShallow WaterIslandBig IslandCoast Trends
1Deep WaterShallow WaterReef5 HexContinues in same direction
2Deep WaterDeep Water1 Hex5 Hex1 hex face left
3Deep WaterShallow Water1 Hex5 Hex1 hex face left
4Deep WaterShallow Water1 Hex6 Hex2 hex faces left
5Shallow WaterDeep Water2 Hex5 HexContinues in same direction
6Deep WaterShallow Water1 Hex5 Hex1 hex face right
7Deep WaterShallow Water1 Hex5 Hex1 hex face right
8Deep WaterShallow Water1 Hex5 Hex2 hex faces right
9Deep WaterReef2 Hex6 HexContinues in same direction
10Shallow WaterShallow Water1 Hex6 Hex Continues in same direction
11Deep WaterShallow Water1 Hex6 Hex1 hex face left
12Deep WaterReef1 Hex7 Hex1 hex face left
13Deep WaterShallow Water2 Hex8 Hex2 hex faces left
14Deep WaterShallow Water1 Hex7 HexContinues in same direction
15ReefIsland1 Hex8 Hex1 hex face right
16Deep WaterShallow Water3 Hex9 Hex1 hex face right
17Deep WaterShallow Water1 Hex10 Hex2 hex faces left
18Deep WaterShallow Water3 Hex11 HexInlet or fjord, coast line comes back out
the same face it entered.
Roll 1d6-2 (min 1) to determine
depth of fjord in hexes.
19Deep WaterIsland4 Hex12 HexContinues in same direction
20IslandShallow WaterBig IslandCoastContinues in same direction
Deep Water vs Shallow Water - There's no set depth dividing the two, shallow water effects (shortening wavelength as determined by the distance between the wave crests and heightening of the crests) occurs when the depth of the water < 1/2 the the wavelength .
For practical purposes, deep water can be considered anywhere where you can't sound the bottom due to the depth.  Sounding the bottom is done with a 150 foot lead line, marked off in 6 foot fathoms.

Reef - a rock or formation lying below mean low water, but protruding up from the surrounding sea floor.

Island - approximate size in hexes or squares if that's what you're mapping on.

Coast - The first time you encounter a coast it will be perpendicular to the direction you are sailing.  Use this column when as you sail along it to determine how the direction of the coast changes in reference to the direction of travel.

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