Sunday, December 20, 2020

Rams and Ironclads - ACW Riverine Naval

  • The following is a rule set I adapted from another set published some 25-30 years ago in some magazine or other, designed for a much smaller scale.  These are designed for an 'open' (non-gridded) table. The vessels I use (still have) are roughly 1:300 scale, but would work probably better at 1:500-700 scale.

Rams and Ironclads

American Civil War River Operations

1. Equipment

Rulers, tape measures, six-sided dice (D6), models or ship 'profiles' in scale from 1:300 to 1:700, protractor with 30, 45 and 60degrees marked, ship stat sheets, movement markers.

Movement markers are square chits with a number on them.  The number signifies nominal speed, which may be modified by the current, or if the ship is reversing.  Placed immediately behind the vessel going forward, the chit is placed at an angle to indicate intention to turn.  Placed in front of the vessel indicates movement astern.  (Note, an arrow on the chit probably makes the intention clearer).
US 'City' Class ironclad gunboats, and monitor

2. Scales:

Ships approximately 1mm to 1 foot (1:300) up to 1mm to 70cm (1:700).
'Ground' scale: 1mm to 1 yard (1:900)
Time scale: 1 move to 1 minute (actual); in game terms 1 turn represents about half an hour. 

USS Lafayette and mortar barges under tow 
by an armed tugboat.

  • Ships move at a rate of 3cm to 1 knot
  • River current is 2 knots.  Add 6cm to ship's move if travelling within 45 deg (degrees) of directly downstream; subtract 6cm from ship's move if travelling within 45deg of directly upstream. (Note that there is no effect upon ships travelling across the current, it being supposed the course steered by the helmsman is taking it into account ).
  • Change of speed: up to 2 knots per turn, unless otherwise stated.
  • Turning: 
    - Riverboats, up to 60deg per turn;
    - Monitors, up to 45deg;
    - Casemate Ironclads up to 30deg;
    - Tugboats and small tenders, up to 90deg.
  • To turn, pivot vessel around the centre of its stern.
  • To reverse, 1/3 'nominal' speed.
    A couple of generic riverboat steamers.  May be used for 
    rams or transports by either side.

4. Order of Play
  • Lay out Movement Markers (See 5).  Note that moves are considered simultaneous, so in intricate situations, they may have to be split further to determine events.  Experience indicated that this was rarely necessary.
  • Make half move straight ahead (see 3) adding or subtracting 1 knot for current.
  • Make the turn, if any ordered.  Dice for yawing if moving at less that the speed of the current , or adrift (tied up, anchored or aground vessels do not dice.  (This makes a turning move look like an angle, rather than a turning circle.  It seems to work!)
  • If appropriate, dice for grounding, putting out fires, repairs, etc
  • Any light guns, musketry, shore batteries, and other guns on vessels not turning, may fire.
  • Resolve ramming.
  • Complete move, if capable
  • Dice for grounding etc.
  • Any light guns, musketry and other guns that did not fire this turn, may fire.
  • Resolve ramming.
    Somewhat 'cartooned style' CSA ram
    steamers.  I call them 'cotton clads', though
    they are wanting their cladding!

5. Move Markers
  • Square counters with numbers to indicate vessel's nominal speed, and an arrow to indicate intention to move straight ahead, or to turn.  
  • These counters are placed upon the playing surface immediately behind the moving vessel, touching its stern.  When moving the vessel, leave the counter in place for the purposes of measurement, until the half-move is complete, and then bring it up to the vessel.  Note that the intention to turn is signalled at the start of the turn, not at the half-way point.
  • Adjustments to speed for current, reversing etc are made to this number on the counter.  Do not allow for current etc before selecting the speed number.
  • Absent an arrow; the top of the number indicates direction of move.  Placed at an angle indicates intention to move, and direction.

    USS Cairo moving full speed, with the river current:

    Place chit at stern = moving ahead.
    8 knots is the maximum speed of this vessel

    Half move: 12cm + 3cm for current

    Full move: 24cm + 6cm for current

    USS Cairo moving full speed, against the river current:

    Place chit

    Half move: 12cm - 3cm for current

    Full move: 24cm - 6cm for current

    USS Cairo, moving downstream, turning to starboard:

  • Chit placed at angle to indicate 
    turn, and direction of turn.
    Half move: 12cm + 3cm for current.

  • Half move: pivot by centre of the stern 
    45deg maximum for this vessel 

    Complete turn: 12 cm + 3cm (current, as still within
    45deg of directly downstream). 

6. Gunnery
  • Gun classes:

  • - Musketry (shipboard sharpshooters)      Up to 20cm
    - Grapeshot/ canister                                 Up to 20cm
    - Point Black Cannon                                Smoothbore (S/B) up to 20cm; Rifles up to 30cm
    - Effective Cannon                                    S/B over 20cm to 50cm; Rifles, over 30cm to 75cm
    - Long Range Cannon                               S/B over 50cm to 100cm; Rifles, over 75cm to 150cm

  • Arcs of fire:
    - Casemate guns - 30deg arc (within 15deg from straight ahead) (Note: a bit generous, but chosen for simplicity).
    - Barbette, deck-mounted guns and shore batteries - 60deg arc. 
    - Pivot guns, for and aft mounted may fire 120deg from centre line.
    - Pivot guns in casemate may fire in a 30deg arc from any one available gunport.
    - Guns mounted in revolving turrets may fire in any sensible direction (i.e. anything that wouldn't damage their own vessel).
    - Guns mounted in fixed turrets count as being in casemates.
    - Shipboard sharpshooters, any direction, at one target only.

  • Armour Classes
    Separate armour classes are assigned to the front, sides, rear and turrets (if any)
    - Monitor Turret ................................11
    - Ironclad over 5"-7" protection .......10
    - Shore battery in casemates ..............9
    - Ironclad over 3"-5" protection..........9
    - Shore Battery in Barbette ................8
    - Ironclad over 1" -3" protection ........8
    - Shore battery unprtected...................8
    - 'Tinclad' or Partial Ironclad ..............7
    - Cotton or wood protection ...............6
    - Unprotected.......................................5

  • Scoring Hits
    For each gun firing at a given target, roll 1 x D6 die, add the Fire Value to the score, and adjust the total as follows:

    +1 - Range Point Blank
    +1 - Target moving at 3 knots or less except shore battery (take current into account)
    +1 - Firer moving at 3 knots or less except shore battery (take current into account)
    -1 - Firing at Long Range
    -1 - New Target this turn, i.e. gun has not so far fired at all, or fired at some other target last time
    -1 - Target bow or stern on to the firer (within 30deg)
    -1 - Firer in flames or filled with steam
    -1 - Under fore from enemy shipboard sharpshooters, or from grapeshot.
    -1 - Mortar firing at stationary vessel (Note, mortars can not affect moving vessels)

    * A HIT is scored if the modified score exceeds the armour value of the target

  •  Effect of Hits
    For each hit on a vessel, roll 1xD6

    6 = Critical Hit (see below)
    5 = Lose 1 knot from top speed
    4 = Lose 1 knot from top speed
    3 = Lose 1 gun, if available, else lose 1/2 knot from top speed
    2 = Lose 1 gun, if available, else lose 1/2 knot from top speed
    1 = Lose 1/2 knot from top speed.

  • More river steamers/ ramming gunboats.  Their 
    armaments are fairly light.

Critical Hits
Roll 2xd6 and add the scores Critical damage is caused according to the following scores.

2 = Freak shot penetrate magazine; vessel blows up and sinks immediately.
3 = Helmsman, Pilot or Ship Captain killed; vessel continues on present course, with no turning (even if ordered) for one whole move (Note - if this happens in the second half of a turning move, then the vessel carries on its new course).
4 = Vessel holed below the waterline and takes on a list or goes down by the bows or stern depending upon the direction of the incoming. 

Lose 1xD6 knots

If listing, opposite side guns can not fire; if down by the bows or stern, the other end guns may not fire.  Monitors can not fire towards the 'up' side or end.

A second such critical hit does not alter the direction of tilt, but does add to loss of speed
5 = Paddlewheel or screw jammed with debris.  Vessel slows to a halt (at 4 knots per turn deceleration).  Roll 1xD6 for number of turns to clear it.  If a 1 is rolled, then the debris is cleared at the end of the turn the damage was received.
6 = Smokestack damaged - lose 2 knots from top speed.  Ship suffers -1 on further gunnery rolls (smoke everywhere!).  Further such hits reduce speed by -2 knots, but can not reduce ship's speed to below 3 knots.
7 = Single casemate gunport damaged and won't open, and gun is left out of action.  1xD6 moves to free it; the gun remaining out of action for that time.  Foe barbette or unprotected guns, lose one, reducing gunnery by one gun.
8 = Steam pipes damaged, loss of pressure.  Acceleration and deceleration reduced to 1 knot per turn.
9 = Same as 4.
10 = Steering damaged - vessel continues on same heading until repairs effected after 1xD6 moves.
11 = FIRE! - Roll 1xD6 to determine number of attempts to put it out.  One attempt is allowed per turn, a score of 6 required if afloat; 5 or 6 if aground or beached.  If the vessel is still on fire after the allowed number of attempts to extinguish, the crew abandon ship, which is left to drift and burn out.  Upon a second such critical hit whilst on fire, the crew will abandon ship immediately.
12 = Boiler holed, vessel fills with steam, and drifts to a halt (at 4 knots the turn).  Crew abandons ship on a D6 roll of 1 or 2.  Otherwise the vessel acts as a floating battery with -1 on gunnery rolls. 

Musketry and Grapeshot
  • Sharpshooters may be carried on riverboat, cottonclads, etc, but not on ironclads.  
  • Any gun may fire grapeshot or canister instead of its normal ammunition.
  • There are two possible effects:
    - Reduces enemy gunnery effectiveness;
    - Roll 2xD6 if a vessel is under musketry or (per gun) grapeshot fire.  Only a score of 3 (see critical Hits) will have any effect.

Firing on Shore battery:
  • If a hit is scored, roll 1xD6.  A 6 knocks out one gun.
    A steam ram, probably in the service of the US 
    navy.  Something like the 'Ellet' rams.

7. Ramming
  • If one vessel rams another, or a collision occurs, the ramming vessel rolls 1xD6.
  • If the collision is bow-to-bow (within a 45deg angle of straight ahead) both sides are considered to be ramming.  In this case ignore penalties to the rammer on scores of 4+.
  • The bonus for having a ram bow is allowed only if the rammer's stem is in contact with the target vessel
  • If a collision occurs with neither bow in contact, both sides roll 1xD6 without adjustment.
  • To the dice rolls, make the following adjustments:
    +1 - Target stationary (drifting, at anchor, or tied up)
    +1 - For every 2 knots over 6 actual speed  ramming vessel travelling (i.e. allow for current)
    +1 - Target side on to rammer within 45deg of perpendicular
    +1 - Rammer equipped with a ram bow
    -1 - Rammer's bow not reinforced
    -1 - Each knot under 4 actual speed rammer is moving
    -1 - bow to bow collision within 45deg of straight ahead

  • Effect of scores:
    6+ = Target loses 2xD6 knots. Vessel slows to this speed if the way forward is clear, else is halted (See 9.  Endurance).  Rammer is halted (for the moment), and loses 1 knot from its top speed.
    4-5 = Target loses 1xD6 knots from top speed; Rammer loses one knot.
    2-3 = No effect
    1 = Rammer loses 1xD6 knots.

8. Torpedoes (Mines)

  • Subsurface torpedoes may be arranged in singles, in 'minefields' or be set adrift
  • In any action, the first occasion that the effect of a particular torpedo or minefield needs to be known, roll 1xD6.  Call the resulting number 'T'.
  • For this and subsequent occasions this torpedo of field is crossed, roll 2xD6.  If the resulting score is less than or equal to 'T' the torpedo explodes, with the following dire consequences:
    5-6 = Vessel loses 3xD6 knots, 1 critical hit (See 9.  Endurance)
    3-4 = Vessel loses 2xD6 knots, 1 critical hit
    1-2 = Vessel loses 1xD6 knots.
  • Single torpedoes, having exploded, have no further effect.  (Note that if 'T' = 1, the torpedo or minefield, is a complete dud.)

  • Spar Torpedoes 
    - A boat or vessel armed with spar torpedoes can not ram and set off its torpedo in the same move.
    -  When a spar torpedo is applied, roll 1xD6
    4-6 = Torpedo explodes under target vessel.  Roll 1xD6 for effect as above
    2-3 = Torpedo fails to explode
    1 = Torpedo gets caught under its own vessel and explodes.  Roll 1xD6 for effect, as above.
    CSS Tennessee - I see there is still work
    needed on this one.

9. Endurance
  • Any vessel whose top speed is reduced to 0 as a result of enemy action, slows to a halt at 4 knots per turn, and drifts with the current.  Each turn, dice for yawing (1,2 = to port; 5,6 = to starboard)
  • Yawing counts as a maximum turn for the type of vessel under consideration
  • If the vessel's top speed drops below 0, the vessel is sinking.   A sinking vessel goes down in 5 + 1xD6 moves.
  • A vessel's top speed may be reduced to 0 or less, but because deceleration when not under power is 4 knots per turn, it may still have sufficient way on to beach itself if close enough to the shore.
  • Instead, a dead in the water of sinking vessel may be taken in tow, to prevent sinking by towing towards the shore, say.
  • A beached or grounded vessel that has 'sunk' is salvageable.
  • A sinking vessel may be hastened on its way to the bottom by further reduction in 'speed' by sinking 1 move early for each further knot in speed lost.  It can therefore go under halfway through a move.
10.  Grounding
  • Except where defined, rivers shoal towards their banks, islands and sandbanks.  Other shoal water may be defined, as required.
  • Whenever any part of a vessel passes closer to the riverbank than its draught expressed in centimeters, it is in danger of running aground.  Roll 1xD6.  If the score is less than or equal to the difference between the vessel's draught and its distance in cm from the shore, the vessel runs aground.  This roll is made as and when it is necessary at the half-way or end point of a move.
  • On subsequent moves, efforts may be made to free the vessel, with a score greater than the draught and distance being required, except that a '6' always frees a vessel.  This roll is made in the middle of a move.
  • Once freed from grounding, the vessel has half a move to get get clear, else it must dice again.  A freeing move may include a turn.
  • A vessel actually touching the riverbank must be towed off unless it is in a recognised anchorage.


11. Towing
  • It takes one move for a vessel to take one other in tow. To signify being in tow, the bow (or stern) of the towed vessel must be in contact with the stern (or possibly bow) of the towing vessel. Note that towed vessels may be towed stern first, and towing vessels my tow in reverse.
  • To pass a towing line between vessels, the appropriate ends of the vessels must be less than 3cm apart.  
  • Towing reduces the nominal speed of a vessel by 1 knot per 5cm or part thereof in length of the towed vessel (and 1 further knot for every vessel more than one being towed {e.g. a string of mortar barges}).
  • Tugs are specialists in towing or pushing.  They may bush one vessel, or tow up to three (reductions in speed permitting).
  • Tugs' top speed is 11 knots, and they may reverse at half nominal speed.
  • Tugs have reinforced bows, are otherwise unprotected, and may mount up to 1 light gun.
12. Ship Stats (Sample)

CSS Tennessee.

Copyright, Archduke Piccolo (Ion A. Dowman)


  1. Wow, splendid ships and nice informations...

    1. Hi Phil -
      I must admit, I haven't played a game of this for well over 20 years. I was lucky to find in my 'bedroom floor' archives a copy I had printed out...
      Archduke Piccolo

  2. Hello there Archduke,

    That is quite a set up there old chap! I love the models - really nice looking. Many thanks for digging out the rules - I have saved a copy of them for a more detailed read later today.

    All the best,


    1. Cheers, David -
      I recall these as a 'One Brain Cell' rule set. Transcribing them, I reckon another five or six brain cells wouldn't go amiss... A deal more complicated than my memory indicated, but I do recall some fun, and fairly quick games at the time.

      You will find, by the way, that ramming is the most reliable weapon...
      All the best,
      Archduke Piccolo

  3. Replies
    1. Thanks. Maudlin Jack -
      Rather neglected and dusty, and some repair work or finishing desirable, but I was fairly pleased with them at the time. Most of them I made about 25 years or so ago. CSS 'Tennessee' was the last of them, although I modified USS 'Kickapoo' rather more recently.
      Archduke Piccolo

  4. I would not have thought it possible, but your ship building gets better and better. These are (even more) fantastic!
    Regards, James

    1. Thanks, James -
      But... these I made well over 25 years ago! They could use a bit of repair work - the earthquakes of 10 years back weren't kind to these ones.
      Archduke Piccolo