Wednesday, June 1, 2016

Ship's Weaponry

There's no question that I often retreat into game design when I'm depressed, as an escape. I should have written this evening; instead, I worked on what's below. Well, we'll right that lack of good judgment tomorrow. In the meantime, the reader reaps the reward.

I didn't get any response to the naval post on Tuesday; but perhaps this will poke the bear into growling:

Ship's Weaponry
Each ship of a certain size has the capacity to be fitted with either ballistae or catapults, which can be used directly against enemy hulls, rigging, siege engines or crew. These are fitted along the left or right hand sides of the ship (port or starboard), enabling fire to be directed outward. For the purpose of our game, an engine cannot be mounted so that it fires directly forward or backward from a ship - because it wasn't done consistently. I haven't been able to find the reason for this, except perhaps that the up and down movement of the stern and bow make such a mount impractical.

Siege engines aboard a ship are supported by ordinary missile weapons, standard to D&D (bows, crossbows, slings, etcetera). Rules that relate to the use of siege engines and these weapons aboard ship are described below.

The amount of weaponry that can be placed aboard ship is not limited only by the amount of weight or deck space that a ship possesses. Much of a ship's deck space is required for the movement of the crew and the management of the ship. Thus, the number of weapons is limited by the number of hardpoints that a ship has. A hardpoint is a location aboard the ship in which a ballista or catapult can be placed. Ships will always have an even number of hardpoints, distributed equally to both sides of the ship. There will be two hardpoints (one on each side) for every three points of hull defensive points a ship possesses (see Ships). For example, a caravel has 3 hardpoints on each side of the ship, while a carrack has 4. A frigate has 5. A yawl has only 1.

There are four siege engines that can be mounted aboard ships: the large ballista, the small ballista, the light catapult and the heavy catapult. Large ballista and heavy catapults each require two hardpoints to mount aboard ship. A small ballista or a light catapult requires only one hardpoint. When two hardpoints are wanted for mounting a heavier weapon, they must both be on the same side of the ship.

Therefore, a frigate with 5 hardpoints on each side of the ship (10 altogether) could mount 4 heavy catapults, two on each side, and 2 light catapults. A frigate could not mount 5 heavy catapults, as the two remaining hardpoints are on opposite sides of the ship.

The following table gives the basic statistics for missile weapons that can be employed during ship-to-ship combat, with ranges adjusted to the width of naval hexes (for missile ranges in direct hand-to-hand combat, see All Weapons).

As with standard combat, the effect of medium and long range on weapons is the same: all weapons that attack at medium range are -2 to hit; those attacking at long range are -5 to hit. In all cases, the chance of a ballista, catapult or any other weapon to hit a standard combat target (creature) is a d20 against that creature's armor class. In all cases of a missile weapon fired directly at an enemy ship, the ship should be considered AC 5. Note that catapults cannot fire at targets that are close up - and that all catapult attacks are done at either medium or long range.

The rounds to load for a ballista or catapult describes the time necessary for a crew of that number. It is possible for a smaller crew to load these weapons. Note, however, that only the small ballista can be loaded by 1 crew; all other weapons must have at least 2 crew or else the tension cannot be created that will enable the engine to fire. Load times for less crew can be worked out as a ratio. In all cases, round fractions up and always add 1 more to the total as a trouble factor:

  • 2 persons loading a heavy catapult will take four times as long as 8 persons, +1 trouble factor = 13 rounds.
  • 7 persons loading a heavy catapult would require 3.429 rounds; this translates to 4, +1 trouble factor = 5 rounds.
  • 1 person loads a small ballista, taking twice as long, +1 trouble factor = 3 rounds.

The time that takes to load counts as the time between firing; once an engine (or any weapon) is fully loaded, the firing of that weapon takes place on the next round - NOT the round in which the weapon's loading was completed. A bow, therefore, loads 1 round, then fires the next; it loads again in the 3rd round, fires in the 4th and so on.

Note that multiple attacks for high level fighters do not apply to loading siege weapons, unless all members of the crew are able to move as quickly; the same is true if one member of a crew is hasted or has imbibed a speed potion; if others must be waited for, than the overall loading of the siege engine is not improved.

Damage to Creatures
The table above gives three forms of damage: hits (direct hits), skipping and shrapnel. Direct hits cause the most damage.

Catapult balls made of solid stone will 'skip,' even after hitting an opponent, potentially causing damage to creatures. See rules for Skipping.

Catapult balls that are constructed of broken stone and low-grade masonry will shatter when hitting a hard object; ballista bolts will also break apart when hitting a hard object. These will both cause damage to creatures even when a miss has occurred. See rules for Shrapnel.

Engines vs. Ships
Only siege engines may be used to directly attack ships. Note that the artillerist must announce before firing that they are aiming at the enemy ship and not its crew. I have decided not to allow pin-pointing a specific target on the enemy ship - although I know this makes no sense, given that a specific creature on an enemy ship CAN be targeted. After trying and discarding a few tables that would allow targeting, I've come to the conclusion that, on the whole, it would not improve the overall experience of ship-to-ship combat, while it does greatly increase complexity. Therefore, all damage will be relatively random. Note, however, that many of the results below can mean damaging multiple parts of enemy's ship: and in any case, it must also be noted that a direct hit against a large, tremendously massive vessel could quite reasonably have no effect whatsoever (bouncing off a particularly supported surface or passing right through rigging without any effect).

Therefore, the player should suppose that expertise, not player desire, is the determining factor in what part of the ship is aimed at: and that if a hit occurs that causes damage, that is what the character (if not the player) meant to aim at.

Once it has been resolved that the enemy's ship has been hit (a successful hit against AC 5), the artillerist will use the Damage Gauge table below to determine the effectiveness of the siege weapon:

As indicated, the artillerist adds the range modifier to the artillerist's number to hit AC zero to determine the effectiveness of the range weapon against the enemy's ship.

For example, suppose that Albert, the lead artillerist with a light catapult's crew is a 8th level fighter, giving him a THACO of 13. He therefore adds +1 to the "gauge" of damage he can cause. If he did not have an artillerist's skill, he would -1 from that gauge, but let's say he does not. This means that when his crew hits a ship at medium range, the shot's gauge is +1+1, or 2; against a ship at long range, the gauge is 1.

This is then compared with the table below:

Against a medium range ship, Albert rolls 2d6 on the '2' column; his chance of causing damage to the ship's hull, rigging, crew or siege engines is high, 5 in 6. At long range, Albert rolls on the '1' column, reducing his chance of causing damage to 15 in 36.

NOTE, a result of no damage does not indicate that the ship has not been hit. It has to be understood that these vessels are powerfully built and are able to be struck with weapons like ballista bolts and catapult balls without any appreciable effect. It takes a very excellent artillerist, working with the best weapons at the ideal range to cause considerable damage to enemy shipping. Most artillery crews will not be led by extraordinarily high level commanders and artillerists, greatly increasing the chance that the weapons they are using will often be ineffectual.

Whew.  I'm done for now.  I'll be working on details regarding the effect of hits against hulls, rigging, engines and crew at some point this week: not tomorrow, I hope.  The page on the wiki for the above content can be found as "Ship's Weaponry."

None of this has been play-tested - though it is based on the Wooden Ships and Iron Men system, reworked for D&D.  It ought to work; eventually, when I am running games again, I'll give it a shot and see how it plays out.


Mark Van Vlack said...

this post is excellent. I was working on a ship centric setting a while back but begged off. This post (and your last about captains) has rekindled that interest.

Tim said...

Wow, this is quite impressive! You're coaxing me into running naval combats at some point.
I like how you've incorporated skills from the background generator. Does this mean, for instance, dogsledding or body surfing might eventually receive a complete rule set? ;)

Alexis Smolensk said...

Everything will get a rule set, if I don't die first.

Scarbrow said...

Currently not giving the Tao as thorough a reading as I should... but as always, showing up to say I'm still here.

I noticed you've not given rules for siege engine ammunition, and yet I understand this should be a major point while on high sea, and an important source of attrition. A few thoughts on how much ammo can be safely transported for a certain size of vessel? How about metallic projectiles? Impractical and maybe not economic, but also more powerful and taking up less space? Or were cannon balls absent until the development of the blackpowder cannon? I've seen cannon balls made of stone, why not metal trebuchet projectiles?

Alexis Smolensk said...

The cost of metal before the industrial revolution - and mass production of metal using steam - is incredible. I've priced out an iron ball; even made of the cheapest form of wrought iron, it is upwards of 500 g.p. per ball. That's a lot of money to throw into the sea. At least on land, it can be collected again. A solid stone ball is pretty cheap, weighs 110 lbs, but even covering that with iron will cost upwards of 60 g.p.

A trebuchet is both too tall for the rigging and has too much outward swing as well - not to mention that the torque would play hell with the ship's integrity (the wood of the deck would creak and twist each time the thing was fired, until it weakened. Trebuchets need to sit on solid ground.

Maxwell Joslyn said...

God damn, Alexis. Ship rules that sound fun? That only puts you ahead of every other DM and every other company-made ruleset I've ever seen. Hell, just having ship rules that (ought to) work, period, puts you way up there.

I'm trying not to sound sycophantic, believe me. But I also wish fervently that the people who charge $40 a book and somehow spend millions on publishing RPGs could just sit down and do the research and write good fucking rules. So I'm inclined to shout out when I see stuff I think is good. One growly bear present.

Maxwell Joslyn said...

Some q's:

I know you don't use regular cannons and firearms because magic is hell for a store of gunpowder, but what about the possibility of iron or stone balls with a bit of powder in the middle and a short fuse to get explosive ordnance for one's catapults?

And that might mean adding a result to the hit table where the ball lodges somewhere in the enemy ship and then goes off.

Any thoughts on magical projectiles? does your world have Greek fire?

Given a ship that's been hit by flaming arrows/ballista bolts, how does the fire spread? I remember learning from your blog that you can easily prevent wooden structure fires by coating the wood in, I think it was pitch and earth, so maybe the ship might not burn at all. Maybe that only applies to land structures and you have to do something different or are out of luck when it comes to sea vessels.

Oddbit said...

Any of this coming from, or applicable to the land lubber siege weaponry?

Alexis Smolensk said...


I'm glad it sounds like fun. I do wonder what it will be like to run when the time comes.

No, I'm not ever introducing gunpowder into my game. Playability reasons. I don't feel it would raise the quality of the tension.

Technically, in 1650 the recipe for Greek Fire had been lost. It's still lost. No one actually knows what it was (though in the last half century a lot of people have tried to claim it).

For the record, flaming arrows are Hollywood myth. Lighting an arrow on fire and then shooting it puts the fire out.

So far, I've been building on the Wooden Ships and Iron Men basic rules: no fire rules there. Don't remember if there are any in the advanced section. Fire will be an issue, because mages will cast spells; but I may have to invent my own rules for that eventually. Probably, will do very little to the hull but will play hell with rigging.

Pitch and sand - and yes, they treated ships with it also.


In the interest of continuity, any rule that applies to siege weapons on ships must apply to those weapons on land.