IRONCLAD GUNBOAT RULES

Last revision 06/28/07

INTRODUCTION

This is intended to be a set of quick-moving, hard-hitting rules, best suited to those who wish to sacrifice a certain amount of realism for the sake of the game. It is not intended to be comprehensive and cover every possible situation that could arise out of the U.S. Civil War. it is, rather, a playable game... a framework around which you can build as elaborate a set of rules as you wish.

The scale of the rules is for approximately 1:1200 ships (such as those made by Houstonís Ships) or something close to this scale. for table top play, the model ships used should be something between 1 inch and 2-1/2 inches long. Larger ships such as 1/600 scale could be used with little change. Much larger ships could be used on the floor or out-of-doors, but be sure to increase the ranges and speeds proportionately when doing so.

To play, three or more people are the ideal number. This allows one person to be the gamemaster. He prepares the situation and referees it, while the others play the game. If you have but two participants, one should prepare the situation and the other should have his choice of sides.

DEDICATION

This game is dedicated to Dr. Michael Lowry who first whetted my interest in this field long ago, and to Robert Whitfield who has sustained my interest in the American Civil War and naval wargaming for years.

This is a derivation of rule concepts first presented by Tom Wham and Don Lowry in their rule set "Ironclad".

EQUIPMENT NEEDED FOR PLAY

You will need miniature ships or counters. These can be homemade but there are many excellent commercial products available. A playing surface of at least 5 by 3 feet will suffice. You will need pens or pencils, six-sided dice (referred to as D6) and ten-sided dice (referred to as D10). The gun angle charts and turning circles are given in the appendices of this set.

MOVEMENT

Because of their superior naval tradition and expertise, the Union player moves first in every turn. The Sequence of action is as follows:
1) Union player moves any or all of his ships. Resolve any Ramming attacks and mark damage. Resolve any grappling and move boarding parties onto enemy vessels.
2) Both players fire all guns that bear and mark off any damage. Mortars fire first, all others second.
3) Confederate player moves any or all of his ships. Resolve any Ramming attacks and mark damage. Resolve any grappling and move boarding parties onto enemy vessels.
4) Both sides fire as in 2) above.
5) Resolve boarding actions and Steam launch combats.
6) Check off one turn on time record. The Game master drifts any ships with the current (if any).

A. Ships move one inch on the table for each knot of speed possible to the real ship.

B. Ships may move up to their current maximum speed as modified by hits taken in the speed boxes. A record should be kept right on the ship card of a ship's current speed.

C. A ship under power may increase speed by 1 knot per turn.

D. A ship may back engines and slow down up to 4 knots per turn.

E. A ship may coast (no power) by losing 2 knots off its previous speed. EXAMPLE: If a ship was cruising at 8 knots and has its boiler blown up, (all speed boxes crossed out), it will coast for four turns before becoming dead in the water.

TURNING THE SHIPS

A. Ships must always turn according to their specified turning circles (as chosen before the game by the gamemaster) although they are permitted to use any turning circle WIDER than their own.
CIRCLE A = 2-1/2" diameter. Use for Union wooden screw and sternwheel gunboats
CIRCLE B = 3-1/2" diameter. Use for Confederate wooden screw and sternwheel gunboats, also for union ships not as handy as above, such as center-wheel armorclad river gunboats and monitors
CIRCLE C = 4-1/2" diameter. Use for Confederate Ironclads.
NOTE 1: Sidewheel steamers can use any circle they wish or may turn in place (pivoting) if moving 2" or less.
NOTE 2: Tugs may push on friendly vessels to turn them more sharply. Any ship moving 2" or less and assisted by tugs may use CIRCLE A.
NOTE 3: Steam launches may turn on a 1" radius.

B. Any number and combination of turns is allowed when moving a ship, provided it does not exceed its current speed.

C. When using the turning circles, match the ship's stack or turret with the marks on the circle and move the ship the desired distance.

FIRING PROCEDURE

A. All guns must be rated as to penetrating ability:

PENETRATION FACTORS

SMOOTHBORESRIFLED GUNS
Gun size:Pen. factorGun size:Pen. factor
12-LB HOWITZER110-LB RIFLE2
24-LB HOWITZER220-LB RIFLE3
32-LB SMOOTHBORE330-LB RIFLE4
6" SMOOTHBORE432-LB RIFLE4
8" SMOOTHBORE542-LB RIFLE5
9" SMOOTHBORE660-LB RIFLE6
11" SMOOTHBORE87" RIFLE7
15" SMOOTHBORE10150-LB RIFLE9

NOTE: The penetration factor indicates the number of armor boxes that the gun can penetrate. Any guns not shown on this chart may be interpolated from it.

EXAMPLE: the 11" smoothbore, the 15" smoothbore and the 150-lb rifle can penetrate A ship with 4" of iron armor (8 armor boxes on the ship card). All other shots would not penetrate.

B. All shots in this game hit, but is important to determine whether the shots penetrate or not. Non-Penetrating hits do much less damage. There are two damage charts, one for penetrating hits and one for non-penetrating hits.

C. The penetration value of each gun is affected by the range to the target. At 0-6" range, the penetration factor of each gun doubles. At over 6' to 12" the penetration value is normal. At over 12" the penetration factor is halved.

D. Ranges are measured from Stack to Stack or Middle of turret to middle of turret. Any blocking terrain or ships, enemy or friendly prevents fire.

DAMAGE FROM GUNS THAT CAN PENETRATE THE TARGET'S ARMOR

CHART A. Sum the total of all guns whose penetration factor (modified) is equal to or greater than the target's armor. These are referred to as penetrating hits. Roll a D10 and consult Chart A:

CHART A
DIE ROLLNUMBER OF GUNS FIRING - Modified by range
123-45-89-1415-1819-2223+
13456789*10*
2-32345678*9*
4-52233456*Critical hit
6-7122334*Critical hitCritical hit
8-91112Critical hitCritical hitCritical hitCritical hit
0Critical hitCritical hitCritical hitCritical hitCritical hitCritical hitCritical hitCritical hit

Cross-index the die roll with the number of guns firing (that penetrate) to obtain the number of hits on the target.

Chart A is used when the firing guns can penetrate the armor of the target. Example: most guns firing at a wooden target or an 8" smoothbore (with a penetration factor of 5) firing at a target with 4 armor boxes. To fire, total the number of guns firing at the target. Consult the appropriate column on chart A, roll the die once and score the result (Usually in hit boxes to be checked off) Refer only to the number of guns firing that can penetrate. Do not sum up penetration factors, just penetrating guns. Each gun may only fire once per turn.

Results that include an asterisk * mean that one boarding party is destroyed or diverted to other work, if one or more boarding parties are embarked on that target ship.

If the result is a Critical hit, roll again on CRITICAL HIT CHART.

CRITICAL HIT CHART - Roll a D6

Die RollResult of hit
1BOILER DAMAGE, 3 speed hits
2WATERLINE HIT, 2 Draft hits (Or 2 guns)
3WATERLINE HIT, 4 Draft hits (or 4 guns)
4STEERING HIT, Rudder jammed hard right 6 turns
5STEERING HIT, Rudder jammed hard left 6 turns
6ROLL AGAIN, WITH RESULT AS BELOW
1,2,3 indicate 4 speed hits
4,5 = all engines disabled
6=Magazine explodes

ANY HITS IN A SECTION ALREADY FULL MUST GO INTO SOME OTHER SECTION. (Target chooses which)

DAMAGE FROM GUNS THAT CAN NOT PENETRATE THE TARGET'S ARMOR

CHART B. Sum the total penetration factors of all guns whose penetration factor (modified) is less than the target's armor. These are referred to as non-penetrating hits. Roll a D10 and consult Chart B:

CHART B
DIE ROLLTOTAL PENETRATION FACTORS FIRING - Modified by range
1-34-89-1516-2425-3536-4849-6364+
112223334
2-311112233
4-5None1111122
6-7NoneNone111112
8-9NoneNoneNone11111
0Lucky hit Lucky hitLucky hitLucky hitLucky hitLucky hitLucky hitLucky hit

LUCKY HIT CHART - Roll a D6

Die RollResult of hit
1Lose 1 armor box
2Lose Smoke stack, if already gone, miss
3Lose 1 midships box (and boarding party - if embarked)
4Rudder jammed hard starboard, 2 turns
5Rudder jammed to port 2 turns
6ROLL AGAIN, WITH RESULT AS BELOW
1,2 Pilot blinded, no course change, 1 turn
3,4 Critical Hit
5,6 = 1 draft hit

Any hits in a section already crossed out must go in some other section. (target chooses where)

GUN RANGES

TYPECLOSE RANGENORMAL RANGEDISTANT RANGE
Howitzers4"8"12"
Smoothbores6"12"4"18"
Rifles12"4"20"4"28"
Mortars 40" Maximum, 6" minimum4"

1. Civil war guns were more effective at close ranges. To reflect this, the following factors affect all gunnery except mortars.

Effect on Penetration: Close = doubles, Distant = halved

Number of guns counted: Close = doubles, Normal = normal, Distant = halved

2. When guns are halved they always lose the benefit of any fractions. EXAMPLES: Two 9" smoothbores are firing at 16" range at a wooden target with a armor factor of 1. Even cut in half the penetration factor is 3 which will penetrate. Two guns are firing and this is halved also to one.

If two 8" smoothbores (penetration factor of 5) are firing at a range of 16" at an Ironclad with an armor factor of 4 then the halved penetration of 2 is not enough to penetrate the armor. Therefore chart B would be used. The total penetration factors of the two guns would be halved to 5, BUT the number of guns firing is also halved at over 12" range. So the effect would be of 1 gun firing with 2 penetration factors. The firing would be resolved under the 1-3 column of chart B.

The same smoothbores firing at the same armored target at under 6" would have a penetration factor of 10 each and would be counted as 4 guns (number of guns doubled at under 6") on chart A.

3. A ship with an armor factor of 0 can always be penetrated by any gun.

TAKING HITS

When a ship is being fired on and the combat charts call for hits to be scored on the vessel, the player being hit usually has the choice of where to distribute the hits, so long as he checks off as may boxes as are called for by the result of the fire. Exceptions to this would occur when the chart specifies the location of the hits, such as exceeding the battering factor on chart B or rolling draft or speed hits on the Critical Hit Chart.

A ship can take as many hits as it has boxes, however, once the draft boxes are all checked off the ship sinks. (unless it is aground already).

CRITICAL HITS These are the most damaging hits a ship can take. They are called for when the proper number is rolled on chart A or when a Lucky hit on Chart B is followed by the appropriate roll on the Lucky Hit chart. If hits are called for in a section that is already gone, the hits must be applied to other empty hit boxes on the ship.

LOSS OF A STACK

Any time a smoke stack is shot away roll a D6 to see the affect on the ship:

Die RollResult of hit
1Fires out, no power for 6 turns
2Pilot house affected by smoke, rudder jammed hard right for next 2 turns
3Pilot house affected by smoke, rudder jammed hard left for next 2 turns
4Lose 1 speed box
5Lose 1 speed box
6Lose 2 speed boxes

MAGAZINE EXPLOSION


This destroys the ship!

ENGINES DISABLED

No power this turn or next turn. At the beginning of each subsequent turn roll a D6 for available power:
1,2,3,4 = no power
5 = 1 knot speed available
6 = 2 knots speed available

RAMMING

Obviously with alternate moves, ramming is quite possible in this game. To successfully ram a target, you must strike its side at an angle of 60 to 90 degrees. Roll two D6 Dice, one white and the other colored. The effect of ramming varies with the speed of execution and whether the ramming ship has a ram.

RAMMING TABLE

Speed of ramming shipWHITE DIE (Effect on target)COLORED DIE (effect on ramming ship)
1 or 2 knots1,2 = 1 draft box1 = 1 draft box
3-6 = No effect2-6 = No effect
3 or 4 knots1,2 = 2 draft boxes1,2 = 1 draft boxes
3-5 = 3 draft boxes3,4 = 1 draft box
6 = 4 draft boxes5,6 = No effect
5 or 6 knots1,2 = 2 draft boxes1,2 = 1 draft box
3,4 = 4 draft boxes3,4 = 2 draft boxes (Check Stack!)
5,6 = 6 draft boxes5,6 = 2 draft boxes**(Check Stack!)
7 or more knots1,2 = 4 draft boxes1,2 = 2 draft box
3,4 = 8 draft boxes3,4 = 2 draft boxes (Check Stack!)
5,6 = 12 draft boxes5,6 = 3 draft boxes**(Check Stack!)

NOTES: ** means the ramming ship has lost its ram. (Check stack) means roll a D6 for each ship. If the result is 1 the ship has lost its stack due to the impact.

Ships without a ram use the table as written. Ramming ships WITH a ram lose one less draft box that called for above.

The above chart represents ironclads ramming wooden ships, Iron on Iron, or Wood on Wood. However, if a wooden ship rams an ironclad reverse the charts. The colored D6 will be the effect on the ironclad and the white die will be the effect on the wooden ship.

SHOALS

Shoal areas may appear in games as per the scenario. Any ships with draft exceeding the possible shoal depth must roll a D6 each time they spend any part of their move in the shoal water. A roll of 1 means the ship is aground. Once aground the ship may not move, change facing or sink until it frees itself. Roll a 1 on a D6 to refloat.

The 1" closest to the shore or riverbank is always shoal.

MINEFIELDS

The game-master or umpire may devise local rules for mines (torpedoes they were then called). You may represent it with an area or areas of different-colored water (colored paper) on the tabletop. Any ship spending any or all of its move in the mined area must test to see if it strikes a torpedo

There should be dummy mined areas as well as the "real" mined areas.

Alternatively, the water area can be divided into numerous areas, each with an identifying letter or number. The player who has the ability to place the mines, notes before the start of the game which areas are mined.

The game-master or the player whose side placed the mines, will roll a D6 for each ship that enters such area. 1,2,3,4 = OK. 5 or 6 means roll again on the Torpedo Hit Table.

RUNNING AGROUND

Players may wish to ground their ships to keep them from sinking (or for any other reason). To do this, simply move the ship so that it runs into the coastline. Of course it might ground in the shoal water first. As soon as it hits the shore it is grounded for the remainder of the game. It may not move or change its facing. It may continue to fire.

MORTAR BOATS

Mortar boats should have a card prepared for them just as any other ship in the game. Mortar ships have a special capability. They always fire first in any fire phase. Mortar ships may only fire if they did not move in this turn.

To fire at a stationary target such as a fort place the mortar burst circle over the target. Maximum range is 40" for 11" or 15" mortars and 30" for smaller mortars. The minimum range is 6". Roll a D10. If the result is 10 then the shell hits and explodes there. Any other result is a miss without effect on the target. Each turn successive turn firing on the exact same spot gives a +1 to the die.

Any mortar hit directly on a ship means a critical hit but being "under the burst circle" has no effect. A hit on a fort or battery silences any guns under the burst circle for this fire phase. A second hit silences the guns for two fire phases. A third hit silences them for the game. Mortar boats may not hit moving targets.

The burst circles for mortars are
15" Mortars have a burst circle of 7/8" in diameter.
11" Mortars have a burst circle of 3/4" in diameter.
Smaller Mortars have a burst circle of 1/2" in diameter.

To reflect the chance of a critical hit on the fort rather than just silencing the guns, roll one additional D10 on any turn that one or more mortar shells hit a fort or battery. If this result is a 10, then a critical hit has occured in addition to any silencing of the batteries. Test on the fort CRITICAL HIT table.

Mortar boats may fire over intervening ships and land. They need not be able to see their target if ground spotters or an anchored friendly spotter ship can see both the target and the mortar boats.

Mortars may not fire at moving targets (because they could not hit them in this period).

SHIP CARDS

A ship card should be prepared for each ship. (Click HERE for our sample ship data cards) To prepare such a card you must know or approximate the number and type of guns, average thickness of armor, draft, and maximum speed. Take into account the quality of the engines. Southern engines were often very unreliable. In general each ship gets the following:

* 1 armor box for each:

* 1 speed box for each 1 knot of speed (Modified by the quality of the engines. A good ship might get additional boxes labeled for each half-knot.

* 1 midships hit box for each 300 tons displacement

* 1 Stack hit box (only 1 no matter how many stacks)

* 1 draft box for each two feet of draft. (these and the midships boxes vary greatly with your judgement of the ability of the ship to take punishment). Each two boxes checked off increase the draft by one foot.

* 1 gun box for each gun on the ship (write the gun's penetration factor inside the box.

* 1 Ram box (if the ship has one)

* Divide the total armor boxes by three to obtain the Battering factor. (This should appear in a circle near the armor boxes) The Battering Factor is NOT a box to be checked off.

WHEN TAKING HITS, THE PLAYER BEING HIT MAY CHECK OFF ANY BOXES HE WISHES. A SHIP IS SUNK WHEN ALL DRAFT BOXES ARE GONE.

FORT CARDS

Prepare these in a manner similar to ship cards, taking into account the amount of armor (usually earth, masonry, or cotton) available to each gun. When all the armor boxes for a specific gun have been crossed off, the gun is eliminated. When a ship shoots at a fort any type of hit (including stack hits) cause the loss of one box (if the armor of the target gun is penetrated. Handle this in the same manner as you would penetrating and non-penetrating hits on ships).

When firing at forts if a "Lucky" or "Critical" hit is obtained, roll a D6 on the following charts. NOTE: If the "Lucky" or "Critical" hit was due to mortar fire, +1 to the die when rolling on the charts below.

Die RollLucky hit on FORTIFICATIONS:
1No effect - Shell is a dud!
21 gun destroyed
31 armor box
41 gun crew takes shelter, does not fire for 1 full turn
52 armor boxes
62 guns destroyed

Die RollCritical hit on FORTIFICATIONS:
12 guns destroyed
22 armor boxes
33 guns destroyed
41 Withering fire, gun crews shelter in bombproofs, no fire from fort for 2 turns
5Roll D6 again: 1,2,3 = 2 guns gestroyed and one armor box per gun.
4,5,6 = Powder magazine explodes, gunners abandon guns for rest of game
6Morale failure in fort, white flag appears!

BOARDING

Confederate ships sometimes carried boarding parties which attempted to board Union vessels & capture or disable them.

During movement, Confederate vessels carrying boarding parties may attempt to come alongside and grapple with Union vessels. if they end their movement touching the Union ship, they may attempt to grapple. Roll a D6 for each boarding party's attempt.
DIE ROLLRESULT
1,2,3Unsuccessful
4,5,6Successful
The boarding party may be transferred to Union vessel's deck if the result is "sucessful.

Each boarding party on deck may be fired on by other union ships during the following fire phase. The ship being boarded may not fire at the Confederates boarding it. Only close range fire may affect boarding parties. Roll once for each hit (Chart A no armor).
DIE ROLLRESULT
1,2,3,4,5No Effect
6Party destroyed
Note that when firing at unarmored ships being boarded, the fire affects the target ship as well as the boarding party. Fire against boarding parties that are aboard ironclads has no affect on the ironclad(it is grape or cannister).

After fire is resolved, roll a D6 for each surviving boarding party on a Union ship.

Die RollEffect on IRONCLADS:
1 No effect
21 gun destroyed**
32 guns destroyed**
4turret jammed, unusable till repaired.
5Rudder chains bound or destroyed Rudder jammed for 3 turns.**
6Ship filled with smoke or noxious gas** Must steam away from battle for rest of game. Cant fire.
Notes on above:

Effect on unarmored ships:
1 boarding party on board, roll a D6:
1,2,3,4 = No effect**
5,6 = melee in progress, issue in doubt ship cant move or fire. Roll again next turn.
2 boarding parties on board, roll a D6:
1,2 = No effect**
3,4,5 = Melee in progress as above.
6 = Ship captured,**
3 boarding parties on board, roll a D6:
1 = No effect**
2,3,4 = Melee in progress as above.
5,6 = Ship captured,**
4 boarding parties on board, roll a D6:
1-2 = Melee in progress as above.
3,4,5,6 = Ship captured**

** Means that boarding party killed, or performing other tasks for remainder of game.

Ships carrying boarding parties must have them noted on their log sheets. The Union player need not know that they are on board till they attempt to grapple. Additional boarding parties may be transferred into "Melees in progress".

At the beginning of the game the Confederate player rolls a D6 and the result is the number of boarding parties formed. Alternatively the game-master may specify the number of boarding parties available to the Confederates.

No ship may embark more than 2 boarding parties.

STEAM LAUNCHES

Small fast steam launches may be used by the Confederates to carry boarding parties (1 each) or spar torpedoes, or to patrol against Union steam launches. The Union navy may use steam launches to patrol against Confederate launches or to carry spar torpedoes. Neither side can use steam launches without the permission of the game-master.

All firing at steam launches is done on CHART A. All guns penetrate (No armor). Long range fire is not allowed (small targets). Check the number of hits on each launch from Chart A, then roll a D6 and consult the table below:

# hitsEffect
1-2 hits: 1,2,3 = No effect, close miss!
4,5 = Engine fire out! no power next turn.
6 = Sunk!
3-4 hits:1,2 = No effect, as above.
3,4 = Engine fire out as above.
5,6 = Sunk!
5-6 hits:1,2 = No effect, as above.
3 = Engine fire out as above.
4,5,6 = Sunk!
7+ hits: 1 = No effect, as above.
2 = Engine fire out as above.
3,4,5,6 = Sunk!.

Steam launches may attempt to grapple with enemy launches and board or sink them. At the end of either player's movement phase, if his steam launch is alongside an enemy launch, roll a D6 to grapple.
Die rollEffect
1,2,3 Unsuccessful
4,5,6 Successful
If successfully grappled, each steam launch rolls a D-6. High die wins the melee and the other boat is captured. Ties mean melee continues till next movement phase, boats locked together. If one side wins with a 6 then enemy boat is sunk. If one side has more launches in melee than the other, +1 to die for each extra launch.

Victorious launches proceed along with their captives to their home base or some point devised by the umpire. They are out of the game.

Steam launches locked in melee may be fired at by either or both sides. Dice for each hit on the pair; 1,2,3=hits Union boat. 4,5,6=hits Confederate boat.

Steam launches carrying spar torpedoes may attempt to ram enemy vessels with them. They must meet requirements for ramming like larger vessels. Consult TORPEDO table.

TORPEDO TABLES

TORPEDOING IRONCLAD Roll a D6:
Dice rollEFFECT ON TORPEDOED SHIP
1,2No effect, a dud!
3,44 draft/4 engine hits/D6 guns destroyed
5,6vessel sunk!

TORPEDOING WOODEN SHIP Roll a D6:
Dice rollEFFECT ON TORPEDOED SHIP
1,2No effect, a dud!
3-6vessel sunk!

Players cannot torpedo steam launches or land installations. All steam launches using spar torpedoes are sunk if the torpedo explodes.

Return to Ironclads Period Page

Go to Ship data sheets for "Ironclad Gunboat"

Go to Appendix - Turning Gauges and Gun Training Arcs for "Ironclad Gunboat"

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