18th Century Siege Rules

We had another excellent attempt at developing the siege rules last night.  Well done Mark, Frank and Russ for ironing out the systems - as you see above you you were following Vauban's principles quite well!

Time Scale

Each turn represents 1 day.  Vauban expected a well coordinated attack to have taken the fortress by the 21st day!

Army Organisation

Defender

For each bastion the defender gets;

1. A unit of engineers 
2. 2 units of heavy guns
3. 2 units of foot
4. 1 CinC
5. 1 unit of medium guns

Besieger

For each bastion the besieger gets;

1. 6 units of foot
2. 2 units of medium guns
3. 1 CinC

In addition the besieger gets a gets a Siege Train consisting of the following;

1. 4 units of engineers
2. 4 units of heavy guns
3. 4 units of siege mortars

The siege mortars may only be used against infantry and artillery units and cannot destroy wall sections.  However, there is no cover defence against mortars.

Formations and deployment

Defender

The defender must deploy within the boundary of the covered way.

Heavy guns and mortars must be placed in a bastion and cannot me moved during the game.  The strength points of the guns may be redeployed from one gun to another during the game.

Medium guns may be placed in a ravelin, on the curtain wall or in a bastion and may be moved during the game.

Foot units, engineers and CinC may be placed on the covered way, ravelins, bastions or in the town and Amy be moved during the game.

Fortress Capacity

A bastion may hold 2 units of heavy guns/mortars and 1 unit of foot.

A ravelin may hold 1 unit of medium guns and 1 unit of foot.

A section of covered way may hold 1 unit of foot.

A section of curtain wall may hold 1 unit of medium guns and 1 unit of foot.

The town area may hold any number of mobile reserves.

Besieger

The besieger begins the game by deploying all foot units in an arc outside the range of the defenders artillery. At the end of turn 1 the 1st parallel is built.

The besieger will then build a further two parallels by advancing saps.

A trench is built at the end of the sap by positioning a section on the centre.

It takes one infantry unit with an attached engineer to build a sap/trench.

Batteries are built directly behind or in front of a section of trench and are specifically for mortars or heavy guns.

If trenches from two different directions do. not meet exactly it will require an additional turn of engineering to make them meet.  Engineering is an exact art and pieces must not be moved once placed!

Sequence of Play

1. The besieger moves any units within the existing network of trenches.  Any foot unit with an engineer attached will attempt to build extra sections of saps/trenches.
2. The defender moves any units within the covered way.  Any foot unit with an engineer attached will attempt to build extra sections of saps/trenches.
3. The besieger fires any units that have not moved.  Foot with battalion guns can fire speculatively as light guns and must if shaken.
4. The defender fires any units that have not moved.  Foot with battalion guns can fire speculatively as light guns and must if shaken.
5. The besieger will conduct musket fire with any foot unit that has not moved or is shaken.
6. The defender will conduct musket fire with any foot unit that has not moved or is shaken.
7. The defender will conduct sorties with any foot unit that has not fired or is shaken.
8. The besieger will conduct assaults with any foot unit that has not fired or is shaken.
9. Trenches, saps and repairs are completed by unshaken units.
10. Shaken markers are removed.

Sortie/Assault

The defender always conducts sorties before the besieger can assault.  The defenders foot units must be placed in a section of covered way during movement before sortieing against the besiegers trench lines and must attack the closest section. Once the besieger is entrenched within the fortress outskirts the defender may launch assaults from the closest defended sections of fortifications (e.g. the ravelins are closest to the covered way).

The besieger may only launch assaults with units placed in the trench parallels and never from saps.  The besieger's foot units must assault the closet section of fortification.  

When launching a sortie or assault the following +/- are added to a D6 roll to determine the outcome;

• -2 if CinC attached.
• -1 if CinC adjacent.
• +1 if the sortie/assault is in daylight.
• +1 for each 8" the unit moves to attack the target.
• +1 if the target unit is entrenched.
• +1 for each friend on the target's flanks.
• -1 if target unit is shaken
• +1 for each additional subsequent attack.

If the roll is higher than the amended die roll then the attack is successful.  The positive difference in die roll is the number of casualties inflicted on the target unit.  If the roll is lower then the attack is a failure.  The negative difference in die roll is the number of casualties inflicted on the attacker - if the attack was at night then the casualties are doubled.

A roll of 6 is always a success regardless of amendments but any minus differences to the die roll are casualties on the attacker (e.g. the amended die roll required to win is 8.  A 6 is rolled therefore the attack is successful but the attacker has taken 2 casualties).  In addition a roll of 6 is a star result against the target and any attached engineers or CinC may be wounded or killed.

Only the target unit rolls for morale if the attacker is successful.  If the target unit is destroyed, routed or forced to retire then the trench, battery or sap occupied by the target is also destroyed.

A roll of 1 is always a fail.  In addition this counts as a star result against the attacker and any attached CinC may be wounded or killed.

Line of Sight/Line of Fire/Cover

Firing is always conducted against the nearest enemy unit.  However, if the CinC is attached then firing is against any chosen target with range and within direct line of sight.

All artillery firing is at +/-45 degrees. 

 Artillery in bastions or ravelins can fire from either face.

Range is measured from the middle of the bastion, ravelin, battery or foot unit to the nearest point of the enemy target.

If the side of a trench or covered way is within 22.5 degrees then the target is enfiladed.  The target is not in cover and counts as a dense target with a shift to the right.

Targets in trenches, saps, batteries and the covered way, if not enfiladed, get 1 shift to the left cover against each firing unit.

Targets in bastions, ravelins or the curtain wall get 2 shifts to the left cover against each firing unit.

There is no cover against mortars. 

1st Parallels cannot be sortied against if the 2nd parallel is complete and the 2nd parallel cannot be sortied against if the 3rd parallel is complete.

Units under fire will always take a morale test from artillery fire regardless of casualties.

Fire and assaults on Fortress Defences

The covered way cannot be destroyed but can be stormed or breached by saps.

Ravelins, bastions and curtain walls cannot be breached until a battery is built upon or beyond the covered way.

Ravelins cannot be assaulted until the adjacent covered way has been taken.  A bastion cannot be assaulted until the adjacent ravelin has been taken.  A section of curtain wall cannot be taken until the adjacent bastions are taken.  

In most sieges the fortress will capitulate once a bastion has been breached - to risk an assault on the curtain wall would mean a possible sacking of the town.

Ravelins, bastions and curtain walls have 15 strength points each.  Once their strength is 0 they are breached. 

Artillery firing from the covered way will fire at full effect with 2x shifts to the right.

An unshaken defending foot unit with attached engineer can attempt to repair any damage if it is occupying the ravelin, bastion or curtain wall.  One D6 is rolled for each turn and strength is recovered up to the original strength of the fortification.

CinC/Engineers

An attached CinC will add +2 to a units morale. 

A CinC in an adjacent trench, sap or fortification will add +1 to morale.

A CinC attached to an artillery unit can direct the fire at any target within range and line of sight.

A CinC attached to a foot unit can direct a sortie at any target within line of sight.

An Engineer attached to a foot unit enables the building of saps/trenches and the repair of fortifications.

An attached CinC or Engineer risks a wound or death when attached to any unit when fired on.  A star result will require a D6 test; 1-3 no effect, 4, 5 wounded and taken out of play for 1 turn, 6 dead.

I think I've covered everything that we have played out so far.  Please let me know if I've missed anything.