Sunday 30 December 2012

Seafaring Rules

Here are some basic rules for getting around the overland map of your saltbox in a boat.

1. Visibility at Sea

Spotting objects at sea depends on the viewer's height and the objects heigh, object size, as well as the lighting.  Here are basic guidelines for the GM to determine what PCs can see.  This is perhaps most relevant in enabling the PCs to discover new islands to explore.  Note that I'm assuming a map with 12 mile grid squares.

Height Definitions(where the character is standing)

  • Sealevel: Deck Height/Beach
  • Elevated: Ship Rigging/Land
  • High: on hill or mountain

Size Definitions(object being viewed)

  • Tiny Ship: skiff/canoe
  • Tall Ship: Cog/Caravel/Carrack
  • Small Island: 3 squares thick or smaller
  • Large Island: more than 3 squares thick

Daytime Visibility

  • Sealevel->Tiny Ship: same square
  • Sealevel->Tall Ship: 1 square away
  • Sealevel->Small Island: 1 square away
  • Sealevel->Large Island: 2 squares away
  • Elevated->Tiny Ship: same square
  • Elevated->Tall Ship: 1 square away
  • Elevated->Small Island: 2 squares away
  • Elevated->Large Island: 3 squares away
  • High->Tiny Ship: same square
  • High->Tall Ship: 1 square away
  • High->Small Island: 3 square away
  • High->Large Island: 4 squares away

Spotting hidden reefs/whirlpools before it's too late

Same square and skill check

Nighttime Visibility:

Sealevel->Ship: same square and skill check

Sealevel->Small Island: same square and skill check or coming quite close without check
Sealevel->Large Island: 1 square away and skill check or same square without check
Sealevel->Hidden Reefs/Whirlpools: same square and skill check
Anywhere->Light Source: similar to daytime visibility i.e. what are the relative elevations

2. Daily Weather

Weather effects sailing movement and can sink ships.  The previous day's weather will have a score between 1 and 10.  Each day, roll a d3-2 and add to previous day's weather value to determine this day's weather.  If you get a result below 1, the result is 1.  If you get a result above 10, the result is 10.

Rainy Season Weather

1: Still
2-9: Favorable
10: Stormy

Dry Season Weather

1-2: Still
3-10: Favourable

3. Movement in the Ocean

So you want to go somewhere in your boat.  There are a few possibilities how to declare this:

  • You see target ship/island and you want to sail to it.  This is pretty basic and you just need to determine your speed.
  • You don't see your target.  Instead you want to sail a certain distance or time period in a given compass direction.  In this case, your Navigator must roll a skill check against his intelligence.  On failure, the DM privately rolls a random direction to displace boat by.

Determining Speed:


  • Still/Favourable Weather: fixed movement rate
    • Skiff 1/2 square per 8 hour day
  • Stormy Weather
    • the boat will move 1d3-1 squares in a random direction


  • Still Weather: 0
  • Favourable weather: depends on wind/load.
    • Skiff: 1d10 squares
    • Carrack: 1d8 squares or 1d4 if loaded with heavy cargo
    • Caravel/Cog: 1d6 squares or 1d3 if loaded with heavy cargo
  • Stormy Weather
    • If continuing to sail, boat gets maximum movement rate (roll your movement die to see how far you get before the storm hits!)
    • If Riding out Storm, the boat will move 1d3-1 squares in a random direction

4. Seaworthiness Checks

If your ship is caught sailing in a storm, roll the Helmsman's Skill.  To determine the severity of the storm, roll 3d6 to determine the DC of the skill check.

Modifiers to roll:

  • Add the seaworthiness of the craft
  • Continue to Sail with low sail: -1 for each movement that day attempted within storm
  • Ride it out with minimal sails: +2
  • Protected Bay: +5
  • Anchored(shallow water): +4
  • Docked: +6
  • Beached: +8

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