GURPS flashback: Naval minis extension

Back when we were playing lots of GURPS, and particularly a Swashbucklers setting, we wanted to use some of my Man-o-War figures to fight out the all too frequent naval battles we engaged in. (Hint: if you are pirate, you really don’t want to fire upon, and sink, treasure-laden ships. We often did anyway because because these rules were really fun.)

These extensions still rely on having the GURPS Swashbucklers book for ship damage tables and stats for ships’ minimum crew, fire power (FP), hull ratings (HR), etc., and a Man-o-War “turning key” is needed. You can find a turning key (and all sorts of stuff) at the Yahoo Group “Sea of Claws,” although you need to join to look at the files. Our playing group was always big and we had players take the offices of Captain, Quartermaster, Bosun, Sailing Master, Master Gunner, and First Mate, some of which are referenced below. As this was fantasy, Vikings sailed in longships, and certain fantasy races had other oddball craft, like dwarf steamships and massive goblin barges. I probably have a list somewhere which I’ll post if there is any interest in these rules.

Turn Sequence:

0. Set-up

1. Initiative

2. Firing and Movement

3. Boarding Actions resolved

Phase 0: Setting up

0.1 Placing crew and Assigning details

All of the ship’s crew must be assigned to any of five locations: Rigging, Forecastle, Poop, Main Deck, and Below Decks. Crew on the Main Deck, Rigging, and Poop or Fo’c’s’le (as appropriate) may board when ships are in contact. The crew Below Decks operate oars and cannon. To sail, a ship must have its “minimum crew” assigned to the Rigging. To move under oars, the ship’s “minimum crew” must be assigned to Below Decks. To operate cannon, at least two sailors per gun to be fired must be below deck. The captain may order up to 10 men to change location per turn. This permits men to be reassigned to areas where the crew have taken casualties.

PC’s must also choose a location, but can freely move about the ship. The Master Gunner must be Below Decks to direct firing or make called shots. The Sailing Master must be on the Poop to handle the ship. The First Mate must be on the Fo’c’s’le. The Bosun must be Below Decks to command rowing. The Captain can take on other responsibilities (Gunner, Sailing Master, or Bosun) if he is in the appropriate area.

0.2 The “battlefield”

The GM should declare wind direction and intensity (dead calm, light winds, normal, strong winds, or storm) before the deployment of ships. To determine the initial wind direction randomly, roll 1d on the Wind Direction Chart (Chart 0.1).

All captains make a Naval Tactics roll. The captain who makes his roll by the most (or misses it by the least) places his ship last. The captain with the worst roll places first.

Phase 1: Initiative

A quick contest of naval tactics determines initiative. The winner may choose to go before or after his opponent. In the event of a tie, the wind changes direction. Roll again on the wind direction chart (0.1). On a 1-4, move the wind point one place toward the direction indicated. A 5 decreases wind intensity one place, a 6 increases it.

Phase 2: Firing and Movement

On his turn, the player may choose to fire and then move, move and then fire, move only, or fire only.

2.1. Movement

Use Man-o-War turning keys. Movement may be by sail, oars, or mechanical paddle wheels. I believe we also used Man-o-War speeds for the base speed of ships.

2.11 Sailing

In a dead calm, ships may not move under sail. In a storm, moving under sail is very dangerous, and most crews will take in the sails and drop the anchor. The captain must make a leadership roll at -3 (or -5 if the crew is Seasoned or more experienced) to convince his men to sail. If a crew attempts to sail in a storm, all Shiphandling rolls are at -6. Failing any Shiphandling roll in a storm will result in damage to the sails (roll a severe chain shot hit). A critical failure (roll missed by 10 or more) indicates that the ship is capsized.

When the wind is blowing, a ship may sail. First, the sailing master makes a Shiphandling roll. His success or failure modifies the distance the ship can move as indicated on the Shiphandling chart (Chart 2.1).

A sailing ship’s maximum speed is determined by its facing relative to the wind at the beginning of the turn. If the ship is sailing across the wind, it uses the first distance listed under speed. If the ship is sailing with the wind behind it, add the speed listed in parentheses. If there is a strong wind, double this figure. In a light wind, ignore it. A ship may not sail into the wind. Any ship which begins it turn facing into the wind must turn before it can move at all. Any ship turning into the wind during its move must immediately stop.

The ship may now move its full speed, as modified by the table. If the captain wants to sail less than the full distance allowed, another Shiphandling roll must be made successfully.

Normally, ships sail in straight lines. To turn during movement, place either the red or blue edge of the turning key alongside the ship model. Then move the model to the other colored edge. This maneuver costs 2″ of move. A ship may turn as often as the player wishes, so long as it has at least 2″ of move left.

2.12 Moving under oars

Some ships may move under oars. Their movement rates are unaffected by the wind. The bosun makes a roll versus (Leadership+Seamanship)/2. Pirates, noblemen, and landlubbers resent rowing and give the bosun a -3 to his roll. Normal sailors do not modify the roll. Nonhuman sailors in fantasy settings also modify the roll by their racial ST bonus/penalty.

Ships moving under oars can turn very swiftly. For any turn of up to 90 degrees, 1″ of movement is used. Turning up to 180 degrees costs 2″.

2.13 Paddle-wheeled steamships

Steam ships are moved with the Piloting skill. The pilot rolls on the shiphandling table (Chart 2.1).

Steam ships may move forward, or backwards at double cost in inches. They turn under the same rules as sailing ships.

2.2 Firing

When a ship fires, place the broadside template next to the model. Any ship under the template can be targeted. Chain shot and Grape shot may only be fired up to medium range. A ship normally fires only one broadside, but both broadsides may be fired if there are targets on either side.

To fire cannons, the Master Gunner must roll against (Gunner+Leadership)/2. This is subject to modifiers; see Chart 2.2. After the modified roll is made, refer to the Gunner’s Chart (Chart 2.3). Successful rolls can increase the effective firepower of the broadside. Critical misses are resolved on the Broadside Critical Miss chart (Chart 2.4).

When a hit is scored, divide the firepower (FP) of the shooter by the hull rating (HR) of the target ship on the Ship Damage Chart (Chart 2.5). This chart lists the quotient and the resulting damage. Use the results in parentheses if the target is braced for war.

2.21 Called Shots

The master gunner may elect to make a called shot for the enemy ship’s mast. To do this, he takes a single gun and aims and loads it himself. Thus occupied, he cannot direct a full broadside, although the gunner’s mate may take direct the men for him. The master gunner rolls against his Gunner skill minus (5 + the distance between ships in inches) to hit the mast. Chain shot decreases this penalty by 3. On a hit the mast is destroyed. Single mast ships cannot sail, and others have their move cut in half.

3. Resolving Boarding Actions

Using representative numbers of crew & officers, fight out a combat in normal GURPS rules. (That is, if the PCs’ ship has forty crew, and the enemy ship has eighty crew, place all of the PCs and twice as many enemies including at least as many “officers” as there are PCs) PCs need to make appropriate survival rolls from ship-to-ship fire, if applicable, before boarding. I believe this part is more or less by-the-book.

4. Charts and Tables

0.1 Wind Direction (GM Rolls 1d)

Roll Result


1 Wind blowing North

2 Wind blowing East

3 ” ” South

4 ” ” West

5 Light Winds, roll again for direction. Another 5 means dead calm. On a 6, roll again ignoring further results of 5 or 6.

6 Strong Winds, roll again for direction. Another 6 indicates a storm is kicking up as the battle

begins. On a 5, roll again ignoring further

results of 5 or 6.

2.1 Shiphandling Chart

(Sailing Master rolls vs. Shiphandling; Steamship Pilots roll vs. Piloting)

Roll made by Bonus to move
10 + +3″
7-9 +2″
4-6 +1″
0-3 0″
-1 to -3 -1″
-4 to -6 -2″
-7 -3″


+3 Crack crew

-1 Green crew

+2 Bosun makes (Leadership+Seamanship)/2 roll

2.2 Firing Modifiers (to Master Gunner’s Firing roll)

-1 Firing at a faster ship

-1 Firing at a smaller ship

-2 Firing at Poop or Fo’c’s’le

-0 Firing at Short Range

-3 Medium Range

-6 Long Range

+2 Firing Chain Shot

-2 Green crew

+2 Crack crew

2.3 Gunner’s Chart (Master Gunner rolls (Gunner+Leadership)/2)

Roll made by FP Bonus


Critical (10+) x 2

7-9 x 1.5

4-6 x 1.25

0-3 0 (i.e., x 1)

-1 – -3 x .5

2.4 Broadside Critical Miss Chart (Roll 3d)

<this is already in the Swashbucklers book>

2.5 Ship Damage Chart (FP/HR = “Ratio”)

Ratio Light Medium Severe


0-.24 1(0)

.25-.49 2(1)

.5-.74 2(2) 1(0)

.75-.99 2(2) 2(1)

1-1.99 2(2) 2(1) 1(0)

2+ 3(2) 2(1) 2(1)

I think this last chart is already in the Swashbucklers book too. In fact I really hope so, because I can’t recall what the parenthetical numbers mean. Critical hit rolls? Something to do with survival rolls?

Anyway, I just noticed this will be my 200 hundredth post!

Published in: on July 17, 2010 at 10:52 am  Leave a Comment  
Tags: , ,

The URI to TrackBack this entry is:

RSS feed for comments on this post.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Wayne's Books

Game Gallery ~ Photo Blog

Ann's Immaterium

Writing, gaming, miniature painting, physical culture, and other dark procrastinations.


Collecting, modelling, painting and wargaming in 28mm

Dragons Never Forget

What were we talking about again?

This Stuff is REALLY Cool

Young scholars enthusiastic to tell you about COOL RESEARCH STUFF

Fail Squad Games

Tabletop games and adventures

Chuck Wendig: Terribleminds

Hey Did You Know I Write Books

Save Vs. Dragon

"We are here on Earth to fart around. Don't let anybody tell you any different."--Kurt Vonnegut


Old School Roleplaying and related musings

Hobgoblin Orange

My return to the world of miniature figure painting and RPGs

The Book Reviews You Can Trust!

Dawn of the Lead

Miniature wargaming and the occasional zombie News

The latest news on and the WordPress community.


Miniature Motivation

Take On Rules

Jeremy Friesen - a poor soul consumed by gaming.

Age of Dusk

Roleplaying, reviews and associated paraphernalia.

Roll to Disbelieve

"We are here on Earth to fart around. Don't let anybody tell you any different."--Kurt Vonnegut

A Book of Creatures

A Complete Guide to Entities of Myth, Legend, and Folklore

Making the Past

Diary of an apprentice swordsmith

Ancient & Medieval Wargaming

Using De Bellis Antiquitatis, with the odd diversion...

Riffing Religion

Prophets should be mocked. I'm doing my part.


Magazine of Thrilling Adventure and Daring Suspense

2 Warps to Neptune

Surveying the Gen X landscape and the origins of geek

Dagger and Brush

Miniature painting, wargaming terrain tutorials, reviews, interviews and painting guides


A lair for gaming, sci-fi, comics, and other geekish pursuits.

I bought these adventure and review them so you don't have to.

9th Key Press

Maps, supplements, and inspiration for roleplaying games.

The Rambling Roleplayer Archives

This site is no longer being updated. Check out the new site at

The History Blog

History fetish? What history fetish?

Sheppard's Crook

The occasional blog of a closet would -be wargamer and modeller


A catch all of books, games, and sundry other interests

The Weekly Sift

making sense of the news one week at a time


Just another site

%d bloggers like this: