GURPS 4e and Sailing Ships Revisited

[hal]

Hello Folks,
It isn't my intention to keep picking away at a problem - especially since it is a problem that has been acknowledged by the game designers as being an issue. I did however, while reading a publication on Naval guns in the age of sail, stumble across this gem that I hadn't expected to find...

A 92 gun ship of the line extracted 200 cannon balls after a battle from its hull, and was readied for battle again within a fortnight.

Since ships of the line practiced a sort of chivalry in which they did not fire upon frigates unless fired upon during battle, it would appear that the battle upon which the 92 gun SOL engaged other ships of the line, and consequently, those 200 cannon balls would not have been anything less than 18 lbrs (standard guns for frigates), but likely would have been 18 lbrs, 24 lbrs, and possibly even 32 lbrs.

This is the first time I've ever found a baseline on just how much punishment in real life a ship could withstand and still remain functional!

[hal]

Correction: Memory being what it is, I was off a wee bit on the details regarding the ship that was pounded.

It was a 98 gun ship. The specific quote I was recalling was:

"There was a curious balance between wooden ships and the number of iron shot they could absorb, something which was to be totally upset by the use of shells. After Lord Howe's Battle of the Glorious First of June 1794, a British 98 gun ship had 200 round-shot removed from her hull, and was ready for action again in a fortnight."

This from NAVAL CANNON by John Munday.

Sorry about that. If anyone is interested in stats on the 98 gun ship of the line, I figure I can probably dig it up somewhere (as to tonnage, type of guns carried, crew carried, etc).

[ericthered]

The idea wasn't to sink ships. The idea was to kill men and damage or capture the ship. In the battle of Trafalgar, only one of the over sixty ships was sunk.

This changed when explosive shells were invented, around the time of the Crimean war.

[vierasmarius]

Originally Posted by ericthered

The idea wasn't to sink ships. The idea was to kill men and damage or capture the ship. In the battle of Trafalgar, only one of the over sixty ships was sunk.

Still, that's counter to the way GURPS handles damage, where the primary purpose is to break the structural integrity of the target, with damage to sublocations and occupants a secondary effect. A 1300 ton ship (550 HP) would be utterly destroyed (beyond -10xHP) by 200 shots from the 42lbr ship's gun from Low Tech (6dx5 pi++). Note that there isn't a 24lbr ship gun listed, but the difference between the 18lbr and 42lbr is a mere 2d, or ~7%.

We can address this somewhat by using the Extreme Damage article from Pyramid 3/34. Using square root of mass instead of cube root for HP gives us 5500 HP, meaning the ship would only likely need to make 1 death check from the punishment described above. Likewise, the revised piercing wound modifiers from the same article could reduce the injury from 1/2 (for Homogenous) to 1/3 or 1/5, depending on exact SM.

Of course, as you point out a main reason to hit ships with cannon was to injure and kill the crew. There's not an easy way to handle that, apart from declaring that any shot that penetrates the hull has a chance of causing casualties (rather than any attack which disables/destroys a ship system, like in Spaceships). For PCs in the line of fire, it could be handled with the Overpenetration and Hitting the Wrong Target rules, but that's messy and probably over-complicated.

[ericthered]

Originally Posted by vierasmarius

Still, that's counter to the way GURPS handles damage, where the primary purpose is to break the structural integrity of the target, with damage to sublocations and occupants a secondary effect. A 1300 ton ship (550 HP) would be utterly destroyed (beyond -10xHP) by 200 shots from the 42lbr ship's gun from Low Tech (6dx5 pi++). Note that there isn't a 24lbr ship gun listed, but the difference between the 18lbr and 42lbr is a mere 2d, or ~7%.

We can address this somewhat by using the Extreme Damage article from Pyramid 3/34. Using square root of mass instead of cube root for HP gives us 5500 HP, meaning the ship would only likely need to make 1 death check from the punishment described above. Likewise, the revised piercing wound modifiers from the same article could reduce the injury from 1/2 (for Homogenous) to 1/3 or 1/5, depending on exact SM.

Of course, as you point out a main reason to hit ships with cannon was to injure and kill the crew. There's not an easy way to handle that, apart from declaring that any shot that penetrates the hull has a chance of causing casualties (rather than any attack which disables/destroys a ship system, like in Spaceships). For PCs in the line of fire, it could be handled with the Overpenetration and Hitting the Wrong Target rules, but that's messy and probably over-complicated.

What's the DR and is it calculated into your statistics?

I suppose it could be argued that a ship has substantially more HP that its ST would otherwise indicate, but I think DR would make the most help.

I'm also a little fuzzy on what tactics looked like exactly at that point, and how often they switched to grape shot or canister when close up.

[vierasmarius]

Originally Posted by ericthered

What's the DR and is it calculated into your statistics?

I suppose it could be argued that a ship has substantially more HP that its ST would otherwise indicate, but I think DR would make the most help.

I was hoping no-one would notice that omission. =P

But really, the DR of wood, while it shouldn't be ignored, is not very much compared to the number of dice being thrown around. For example, the HMS Victory (Lord Nelson's 3500 ton flagship) had a hull 2ft thick at the waterline, but it's not clear how much of that would count as "armor" (DR) versus "structure" (HP). At the most generous, it would give up to DR 24 for 24" of wood, which reduces damage by about 23% (from 105 penetrating damage to 81, before wound mods). That is being the most generous with wooden armor; I suspect half or less of that thickness should actually be counted as armor instead of structure.

200 shots dealing 40 injury each would still reduce the 1300 ton, 550 HP ship to splinters, so one of the optional rules I mentioned is still needed to make this situation feasible. After running these numbers, I'm pretty satisfied that basing HP on square- rather than cube-root of mass is sufficient to achieve relatively realistic results.

[Hans Rancke-Madsen]

The damage that caused most ships to surrender was men killed and guns dismounted. Basically becoming unable to fight back. At some point the ship couldn't return fire and surrendered. (This does not count ships carried by boarding actions).


Hans

[vierasmarius]

Originally Posted by Hans Rancke-Madsen

The damage that caused most ships to surrender was men killed and guns dismounted. Basically becoming unable to fight back. At some point the ship couldn't return fire and surrendered. (This does not count ships carried by boarding actions).


Hans

Right. In addition to making ship hulls more resilient (as I attempted above) we also need better rules for shipboard casualties. Any suggestions?

[Anaraxes]

Also, sail, mast, and rigging damage -- a "mobility kill" in later jargon. Both crew and rigging had special ammunition designed for those targets (grapeshot, chainshot) instead of just pounding on the hull.

The guns probably get little benefit from DR, since they themselves have to be run out gunports to fire.

A Napoleonic game might find it worth while to have specific ship hit tables and target locations. A fair number of unaimed shots would hit "gunport" as well as "hull" simply by chance.

Rudder hits and increased damage from crossing the T would probably require facing and a tactical map, but I supposed you could just award bonuses for a Quick Contest of Shiphandling.

[ericthered]

Ok, I'm sorry, but the difference between an 18 lb gun and a 42 pound gun being 7% is just plain WRONG.

that aside:
I suppose the trick is that these ships need to be able to tank 200 p++ shots without too much problem. Making the Homogeneous reduces things to 100 damage a shot, but to take 100 of those without making a death check means the thing has 10,000 hp. And thats about scale we're looking at. using cube root turns the 350 hp ship into a 2100 hp ship if you rotate on 10, or 6500 hp ship if you rotate on 1. The 21 hp ship is pretty dead after 100 shots, and can go down to 20. the 6500 hp ship starts worrying at 60 shots, which sounds about right, and can be tweaked with by tweaking the death roll.

of course, then you have to consider that when they dug 200 balls out of the wood, those were the ones that got stuck, and 92 balls would fly in each broadside at a target the rough size of a barn.

So we way want to tone down the damage those guns are doing, or separate hull sections that track damage separately.

Its also worth noting that the wood used to construct these ships was really strong wood, and nothing to laugh at.