Cannons

[Malus Black]

As I'm making an adventure set in Dementlieu I've found that I need some sort of stats for cannons. The problem is that I can't find them anywhere. So, here's my initial idea:

A shot from a cannon works much like a line effect. Anything in the path of the line takes 6d6 damage, with a reflex save ( DC 18 ) for half. For each 30 ft. from the cannon a target is, the DC is lowered by 1.

If the cannon is not properly secured, the force of the shot will throw it 15 feet back, dealing 2d6 damage ( reflex DC 14 for half ) to anything in its path.

Reloading a cannon takes 3 full rounds for a single person, with 1 less round per person helping. The reloading time cannot be less than 1 full round.

So, the issues I want to sort out are:
1) No skill is actually involved in firing the cannon. I was thinking an Intelligence check against the touch AC of the target, with a range increment of 30 ft. A miss indicates that it has gone 1d3x5 ft. to either the left or the right of the target ( roll 1d2 ), where it continues as usual.

2) The range of a cannon. I haven't the faintest idea what it is.

So, any ideas?

[Ultramyth]

Range of a 'cannon', that is, a 42 pounder:


Item: Cannon
Cost: 24000 gp
Damage: 8d6
Critical: x3
Range Increment: 600 ft.
Weight: 7500 lb.
Standard Crew: 6+
Weight of Shot: 42-pounder

That's derived from historically accurate information. That's a very big gun, the kind mounted on warships, not portable in combat.

A culverin, two sizes down (after demi-cannon) is more likely to be used in the field:

Item: Culverin
Cost: 12000 gp
Damage: 6d6
Critical: x3
Range Increment: 450 ft.
Weight: 4700 lb.
Standard Crew: 4
Weight of Shot: 18-pounder

Most cannons have an effective range of 1500-2000 yards. Depending on the sort of range you're firing at, I'd either use the catapault rules (p.99 of the DMG) for long range fire and the ballista rules (size penalty) for closer ranges. Also, due to the size of a cannon, I'd make it -6 for a cannon, and -4 for a culverin.

As for your line idea, it's great, and realistic (think of those scenes in The Patriot). However, you need to take a few things into consideration. Cannons still fire on an arc, not a straight line, so say that where the ball hits is where you start applying damage from. If the initial damage kills its target, the ball continues moving, but deals one die lower damage to the next hit target, until it stops when a character survives the attack, or it runs out of dice.

For example, first target, deals 6d6 damage (lets say 20), killing the target. The next person in line faces 5d6 on a successful hit (15) and he too dies, but the third takes 4d6 (say, 12) and survives. The ball stops there.

That's all I can think of "on the spot".

[ScS of the Fraternity]

Also remember that there is a difference in the quality of a cannon hit. In a good hit, cannons bounce on the ground, exacly like the line of effect described above. A "miss" may still hit the right area, but hits the ground straight.
In either case, the cannon ball is not the only thing that targets need to be worried about. When the ball hits a tighly packed mass of troops the resulting impact sends debris flying. Shattered pikes and other debris can slay people not actually directly by the ball.
So, perhaps the line should be 15 feet wide - unless the whole area is empty space.

I might suggest making a cannon attack an attack with a grenade weapon, complete range increments, grenade scatter die and other penalities.
A hit only causes a burst of 15 feet diameter, a hit that succeeds by 4 or more causes a line of effect.
A hit where the line or circle of effect hits a target calls for a reflex save, with a penalty equal to their size AC modifier - groups of people would be considered 1 target, with a size determined by # (4=large, 9=huge, 16 gar, 25=C).

This might seem a little deadly, but remember that most of the artillery men will be warriors of low level, so most cannon attacks will be misses.

[Ultramyth]

A 15-foot radius, isn't that a bit large? I'm not sure I like the idea of grouping targets together, but it might otherwise work.

Perhaps they should all make reflex saves vs the attack score of the gunner if the ball threaten's their square.

[Malus Black]

Okay, how about this:

Firing a cannon
The character firing the cannon must first succeed at a modified attack roll using only the base attack bonus + the character's intelligence modifier + range penalty against DC 15. If the roll succeeds, the cannon hits the designated square. If it fails, the cannonball hits a square 1d3x5 feet per 100 feet shot from the target in a random direction (roll 1d8 as if using a grenade-like weapon).

Once the cannonball strikes the ground, the character firing the cannon makes a bounce roll against DC 15. This roll is a modified attack roll using only the base attack bonus + the character's intelligence modifier + additional modifiers (see below). If it succeeds, the cannonball bounces 1d6x10 feet in the same direction it was heading, dealing damage to anything in its path. The number of damage dice is lowered by 1 for each target it strikes, and the cannonball stops completely if it does not deal any damage at all to a target of Medium or smaller size(due to damage reduction etc.), or not enough damage to kill it for Large or larger creatures.

If the bounce roll fails, the cannonball impacts where it hits, dealing damage to that square and half this damage (3d6 for a culverin, for example) to squares within a 10 feet radius (reflex save with DC equal to the original attack roll to halve damage).

Bounce roll modifiers:
Very hard ground +2
Hard ground +1
Soft ground -1
Very soft ground -2
Missed target -1 per 10 feet missed

Case shots
A cannon can also be used to fire a case shot, a shower of metal pieces. When so used, the character firing the cannon makes a modified attack roll using only the base attack bonus + the character's intelligence modifier. This is the DC for the reflex save targets must make.

The case shot works as a cone effect with a radius of 10 feet per damage dice of the cannon (60 feet for a culverin, for example). For each 10 feet from the cannon a target is, the damage is lessened by 1 dice (for example, a target standing 25 feet from a culverin would take 4d6 points of damage). Targets caught within the cone can make a reflex save to halve the damage.

Reloading
Reloading a cannon takes 6 full rounds, minus two rounds per person helping, to a minimum of 2 full rounds.

Misfire
If the character firing a cannon rolls a natural 1, a misfire may occur. Roll another attack. If this does not meet the DC of 15, a misfire occurs. Roll 1d20 and consult the chart below.

1 - 15 - Jam
16 - 19 - Malfunction
20 - Explosion

If a jam occurs, three full rounds minus one per person helping, to a minimum of one full round, must be used before the cannon can be fired again.
A malfunction is more serious than a jam and takes twice as long to fix. In both these cases, the time it takes to reload the cannon is not counted.
At times, the entire cannon may explode. It deals piercing and fire damage equal to its ordinary damage to targets within 10 feet of the cannon, and half this to targets in the next 10 feet.

[Ultramyth]

Those are pretty damned good rules. That's teamwork.

[Hashmalum]

Very good! Now all we need are rules for firing a patriarch-level vampire out of the cannon, and we'll be all set :P

[Malus Black]

Those are pretty damned good rules. That's teamwork.

Thanks. You know what they say about two heads tasting... er... thinking better than one.

Very good! Now all we need are rules for firing a patriarch-level vampire out of the cannon, and we'll be all set.

On the off chance it comes up I'd assign a horror save for being pelted with patriarch bits.

[Hashmalum]

On the off chance it comes up I'd assign a horror save for being pelted with patriarch bits.

But is one of those bits the magical flying headless torso?

[The Nightmare Man]

Would there need to be some type of check for the recoil of a standard artillery fixture? Not so much for the people operating it, but rather for the platform or area it is standing on.

[Malus Black]

I really don't know. While it might be realistic, I'm trying to keep the rules relatively few and simple. I wrote about the effects of not securing the cannon in my first post (come to think of it, that rule might need revising), but other than that I think it's not neccessary.

Also, does anyone know how fast (or slow) you can move a cannon? Speed of 15 feet, can't run, perhaps?

[Ultramyth]

I've been doing some research for my next book which focuses on bringing a renaissance to a medieval fantasy setting. There's a number of obscure websites out there, one of which mentions recoil, but that's regarding shipborne cannon.

Recoil, with ropes, and a 6-10 man crew for a cannon sized weapon is somewhere between 5-10 feet. I can't find the damned link now.

Considering the weights of the cannons (even a culverin is well over two short tonnes) they most likely need to be pulled by horse, any could only be moved very slowly on the battlefield by hand. I would say 5 ft/round, 10 max.

[Malus Black]

With that much recoil with ropes I wonder how much there is without. Also, what other ways are there of securing a cannon than ropes? It's rather hard to find something to tie it to in the middle of a battlefield.

And 10 ft. for culverin sounds good - it's hard, but not impossible to move it, so that you can position it better as the battle progresses but it's more rewarding if you placed it well at the beginning. And I suppose an ordinary cannon is too heavy to be moved by anything weaker than a horse.

[tec-goblin]

BTW, in Modern, cannons do d12s (for example, a 12 pounder does 4d12, an 18 pounder 5d12).

[Steve Miller]

Just so it's asked and out of the way...

If a darklord fires himself out of a cannon, can he cross the domain border? What happens if he can't?

(BTW, nice cannon rules! Does someone want to formally label them as OGL so I can appropriate them for a d20 Tools update? )