Friday, March 8, 2019

Preliminary Work to Ship's Weapons

UPDATE: the mangonel as it appears on this page is inaccurate, as I write about here.  Please disregard content on the page and in the comments about this siege weapon.

Basic Rule for what to do when research fails ~ concentrate on the goal at hand.

If we take some time to look on line to learn what we can about siege weapons, it becomes apparent in short order that: a) no one can agree on what anything is; b) no one can agree on how it works; c) there are no legitimate statistics for weight of machine, range, missile, effect or durability; and d) there are hundreds of little groups making their own siege engines with 2x4s, creating noise that goofs up any real scholarship on the internet.

I've been down this road a couple of times before, only to come up short.  So ... we dispense with research, remember a game world isn't an accurate simulation and come up with a solution that pays no attention to accuracy.

What we need is a sliding scale of ship's weapons, the most important thing being that they differ from one another not only in power but in specific benefit.  To that end, I've created this table:

It doesn't matter what any of these things are; only what they are in relationship to each other.  Generally, I'm treating a mangonel as a light counterbalanced catapult firing a small ball that is good for distance and momentum but relatively poor against crew/rigging; it also requires a big ship.  The catapults are torque weapons, fair against the hull and rigging, with the light catapult being a cheap yet effective weapon against crew.  The heavy ballista is light, has good range, can fire at a shorter range and again, a good anti-crew weapon.  The light ballista is lighter still.

I'll put up to other tables here that will help explain the damage, but first let me discuss hardpoints and the limit to ship size.  A hardpoint is a location on a ship where a siege engine can be emplaced.  On the table above, where it addresses damage to hardpoint, it means to the siege engine that has been put on that hardpoint ~ mangonel, catapult or ballista.

It takes a bigger ship to mount a mangonel, with the tonnage shown being cumulative.  Two mangonels would require a ship of 120 tons; two heavy catapults, a ship of 80 tons.  An Indian carrack, at 1,005 tons, has 20 hardpoints and could mount 16 mangonels ... which could quickly destroy ships at +1 hull damage (see below).  This is unlikely, however, as that would also mean sacrificing 54 tons of cargo space to heavy weapons.  A merchant ship (and most of them would be) would do with less firepower, though a warship would load up.

When firing a siege weapon, the artillery crew decides whether to fire at the hull or the rigging.  Whichever is aimed at, rolls are made for hits on the tables below.  We'll start the with hull, the more interesting one.

Yes, I know.  I dislike hit location as well.  But firing at a moving ship with a ballistic weapon is not like firing a bow at a combatant, so considerations have to be made.  All siege weapons use the above table.  The artillerist pointing the weapon aims according to his or her THAC0, and if aiming at the hull must hit AC 3.  A natural 20 indicates a critical hit.  Ordinary hits roll only on the left table, applying modifiers to hull/rigging damage as shown on the siege engine table.  Damage to crew is resolved as normal D&D.  A destroyed hardpoint can't be repaired; a wrecked hardpoint can be rebuilt and restored in 24 hours, a damaged hardpoint can be rigged to be impaired, which than then be restored in an hour and an offset hardpoint can be reset in half an hour.

When rolling a critical hit, both tables are rolled upon and both always apply.  For example, a 20 on the left and a 12 on the right would mean that the enemy ship lost hull and rigging and its crew was forced to make a morale check.  I haven't made morale rules yet for shipboard combat, but that's coming.

Hits to the crew select a random crew member; if the player designates a specific point of the ship being fired at, then hits to a crew member will be a random determination of crew nearest that point.  Most of the time, it will be difficult to identify and target the captain, who will be concealed by other crew members, housings, masts and whatever else might be in the way.  Still, it's possible.

Which hardpoint is hit is also rolled randomly in the same fashion.

I suppose I shall have to create a table identifying the effect of magic spells against rigging and hull.

Here is the targeting rigging table:

This is still, more or less, following a framework created by Wooden Ships & Iron Men, but of course it is much more gritty and detailed as befitting D&D.

I have more to do to nail down a lot of the details on this subject, particularly how long it takes to load a siege engine, the size of its crew and I think probably that more crew means faster reloads to a point.  I admit, however, that my premise is that ships should be very hard to sink with ship's weapons alone. At best, smashing the rigging or getting lucky with a critical hit will reduce a ship's yare, so that it will move slower and make it dangerous to turn into the wind.

I also expect that some sea battles will simply be two to three rounds of getting turned around before the faster ship simply sails away.  The players at low level are likely to have very fast ships, so that they shouldn't be concerned about a big pirate ship, unless encountering it in the fog or some such.  If the players eventually get a big ship, they'll have to decide for themselves how best to use it if they want to chase down victims.  There might be spells such as haste that can be used to let one brilliant crewman act more quickly, enabling the ship to catch the wind a little better ... and there's always sage abilities that could improve a ship's crew to the point where they could improve on the ship's base yare.  I'll get to those rules too.

Still a lot to do, but I feel like I'm over a hump.  I just hope noisms doesn't mind that I'm writing all this prescriptive content on how to run ship combats.

Relax.  That's just a joke.


Drain said...

This is amazing. That is all.

Homer2101 said...

Looks interesting. Two points:

(1) How would you mount 16 mangonels on a carrack? I know you are not looking for historical accuracy, but it does not seem a 1000-ton carrack has sufficient deck space for 16 3-ton mangonels. Unless the crew takes down all of the masts and rigging. Not a question of historical accuracy, but rather whether such a thing is physically possible at all.

The hardpoint system itself is a well-tested method for representing ship weapons, but it might be better to divide into 'heavy' hardpoints that can fit big things and 'light' hardpoints for small things.

(2) You write: " The players at low level are likely to have very fast ships, so that they shouldn't be concerned about a big pirate ship, unless encountering it in the fog or some such. If the players eventually get a big ship, they'll have to decide for themselves how best to use it if they want to chase down victims. "

Ship speed does not correlate to ship size and tonnage. Ship speed is principally a function of propulsive power (sail area) and hull form, particularly the ratio of beam to length. A big ship with a long hull and lots of sail area, like a clipper, will be faster than a small ship with a short and beamy hull.

Ship turning radius works the other way. At a given speed, a long and thin ship with a small rudder area will have a larger turning radius than a short ship with a large rudder area. Ignoring modern things like Azipods. For example, American battleships had tighter turning circles than their escort destroyers, despite being twenty times their escorts' mass.

So a low-level party might only be able to afford a small ship, and they might wish to buy the fastest ship they can, but their ship shouldn't necessarily be faster than a bigger ship that can mount more sail.

Instead of progressing from fast and small to slow and big ships, what if the progression was by tonnage? At low levels a party might be able to afford only 100 tons of ship, but can tailor it for their purpose. Or travel to a place that makes the kind of ship they want. This might give players an interesting set of choices as they become wealthier. For example, if operating in an enclosed sea like the Seto Inland Sea, they might buy a galley, which can maneuver freely against the wind, and be able to get upwind of any big pirate with lots of sail but no oars; or any merchant if they want to engage in some piracy of their own. Or buy a fat-bottomed carrack and stay to safer waters.

Alexis Smolensk said...


My calculations are that an Indian Carrack has a beam of 46 feet. I'm calculating a mangonel at 7 by 10 feet. More than enough room. The stern castle is stepped, so that the high stern supports four mangonels at 5 and 7 o'clock, the lower stern castle, wider than amidships, carries 3 on each side, amidships carries 2 on each side and the forecastle carries the remaining four. I determined the beam width by retaining the ratio of a standard carrack, then calculated the tonnage in 3 dimensions. I don't think you understand how big the ship had to be.

Regarding the hardpoint system, feel free to go your own way.

I believe your argument about ship speeds applies to post industrial age; my research disputes your opinion.

Ship turning here is according to rules applied in BOTH Wooden Ships & Iron Men (describing much, much bigger ships than what occurs in the 17th century of my world) and the game Trireme (19 centuries before my world takes place). I think these rules work, despite your objections.

Take note that a Caravel is very fast in my rule system. Under the control of a good crew, it absolutely could outperform a much smaller, lighter yare, particularly if the latter is handled by an inferior crew. You haven't seen all my rules yet, and none at all about crew quality. Before you FIX the system, maybe you should see it all.

And keep an open mind.

Alternatively, I encourage you to go create your own system. In 40 years of D&D, no one has, so you might go easy on busting my balls as I make this attempt.

Alexis Smolensk said...

No one has to this extent of grittiness, at least.

Homer2101 said...

Thanks for the response.

Apologies. I wasn't clear in my question. I wasn't asking whether 16 mangonels would physically fit on the deck, but whether they could be mounted in a useful manner.

Consider this model of the Madre de Deus. The ship was built in 1589. It was 165 feet long, had a beam of 47 feet, and had a cargo capacity of 900 tons. It seems to match your Indian Carrack. The high stern castle has rigging on both sides and to stern, blocking firing lines. The forecastle has rigging on both sides and forward, also blocking firing lines. Possibly I am missing something, but it seems that mangonels mounted there will be useless for anything other than shooting at the ship's own main deck unless the crew takes down the masts and rigging. Part of amidships likewise is occupied by rigging, which will block mangonels' fire.

Once I account for the rigging, it look like you can put four or maybe five mangonels on each side, or eight to ten mangonels in total, before the rigging gets in the way. I don't know if it's practical to take down some rigging and/or masts before a battle. The Greeks would take down their triremes' sails and masts before battle and leave them ashore, but these were oar-powered and not sail-powered ships, with a much simpler setup.

I will wait for the full movement system before commenting further on ship movement.

Alexis Smolensk said...

The Madre de Deus had 32 cannon; they could afford to add what rigging they wanted to as they didn't have to manage the kind of weapons I'm supplying. If cannon did not exist, as my world stipulates, because a single magician could light a stack of powder at 80 feet and blow your ship to hell at will, then they'd build the deck differently.

It does no good to argue earth examples. As I said at the start of the post, what ho? The idea is to create an exciting, interesting ship battle. A big ship with lots of guns is exciting. Ships moving at different speeds, with different powers, brings variety and challenge. A lot of the same ships, moving in the same way, with too few guns, would be boring.

For game purposes, big ships have to go slower than small ships, because it makes for a more interesting combat. If a big ship wins every battle, because its the biggest ship, then there is no game. It's boring.

I don't care about real Earth ships in 1650. This is a fantasy world with magic. The ships are different because the world is different.