Are warships too fragile in GURPS?

[Anthony]

There are several problems here:

• Realistically, 'damage' is a function of the width and depth of the hole, relative to the dimensions of the target. GURPS handles the concept of 'width of hole' through the pi-/pi/pi+/pi++ figures, but ignores the second constraint of 'relative to the dimensions of the target'. Even without IT:Unliving, a SM +2 target should basically treat pi++ as pi, and a SM +4 target should treat pi++ as pi- (this is not easily generalized to other damage types).
• GURPS assigns hit points strictly based on weight. While simple, this isn't terribly accurate; not all objects have the same portion of their mass bound up in structure, and not all structures are equally strong.
• The entire concept of hit points is dubious against most targets. Actually turning a human into hamburger, or a vehicle into scrap metal, requires a staggering amount of punishment. For objects that don't bleed, a hit that doesn't strike something critical has fairly marginal effects. Note that taking on water, for ships, is similar to bleeding -- with the same level of frame, a building is far tougher than a ship.

[ronom]

Yes, and treat damage control as roleplaying or hard to kill:rolling to fight the fire that is the biggest danger. If memory serves, a US Navy cruiser's black powder (used for salutes) cooked off, endangering the vessel>

[RGTraynor]

Originally Posted by Fred Brackin

Especially how they can handle fires. Fire is the great ship-killer. Almost no major warship is ever hammered to pieces by direct weapons hits. It's mostly fire or secondary explosions.

Hell, that was the case in the Age of Sail as well; it's nothing particularly new. Unless there was a very dramatic disparity in ship size -- and we're talking two-decker vs sloop -- there are hundreds of examples of artillery duels lasting for hours, often at point blank range, with no one sunk.

I have to agree with a couple posters, though; GURPS isn't a wargame, and the degree to which it accurately and reliably replicates naval combat is limited. I've had a great deal of naval combat in my campaign, but my goal is more storytelling from the PCs' perspective.

[Mgellis]

Originally Posted by RGTraynor

Hell, that was the case in the Age of Sail as well; it's nothing particularly new. Unless there was a very dramatic disparity in ship size -- and we're talking two-decker vs sloop -- there are hundreds of examples of artillery duels lasting for hours, often at point blank range, with no one sunk.

I have to agree with a couple posters, though; GURPS isn't a wargame, and the degree to which it accurately and reliably replicates naval combat is limited. I've had a great deal of naval combat in my campaign, but my goal is more storytelling from the PCs' perspective.

Hmmm...in some cases, the flaws with vehicle combat could actually be advantageous. If you had to roll dozens of time to resolve a battle between two sailing ships, I think it would get rather boring. However, with the RAW, you're really talking about a few broadsides finishing the battle one way or another. That sounds like it's not historically accurate, but it would speed the game up. I'm just concerned about going too far in the other direction, with vehicles either being healthy or dead, with nothing in between.

One could solve the more egregious problems with a few house rules; I am just generally wary of house rules--it is a slippery slope; you open the door for one house rule and suddenly you've got dozens fouling up the works! :)

Among other things, you could build some large vehicles with some form of Injury Tolerance: Damage Reduction against Piercing and Impaling damage. The 4,000-ton frigate still has DR 35 HP 800, but bullets don't really do all that much damage; to really hurt a big ship, you need either a fire or an explosion.

Mark

[Fred Brackin]

Originally Posted by Mgellis

Among other things, you could build some large vehicles with some form of Injury Tolerance: Damage Reduction against Piercing and Impaling damage. The 4,000-ton frigate still has DR 35 HP 800, but bullets don't really do all that much damage; to really hurt a big ship, you need either a fire or an explosion.

If I was starting from scratch, I'd give vehicles a "Structural DR". This would be the point below which no attack could do enough damage to actually impact the _structure_ of the vehicle.

Pierce the hull, damage components but not break up the whole vehicle.

Fred Brackin

[elustran]

Originally Posted by Anthony

Realistically, 'damage' is a function of the width and depth of the hole, relative to the dimensions of the target. GURPS handles the concept of 'width of hole' through the pi-/pi/pi+/pi++ figures, but ignores the second constraint of 'relative to the dimensions of the target'. Even without IT:Unliving, a SM +2 target should basically treat pi++ as pi, and a SM +4 target should treat pi++ as pi- (this is not easily generalized to other damage types).

I agree... earlier in the thread I wrote up some rules to do this based on a comparison of the linear measurement of SM vs. projectile diameter. They COULD be cumbersome, but if they're included with vehicle statistics, they should be easy to handle. Your way works, but fails at the high end because of the huge range that qualifies as pi++ - a 120mm round and a 20mm round are both pi++, but have very different effects on larger targets and even the frigate being discussed at the beginning of the thread is probably SM +11, maybe +10.

GURPS assigns hit points strictly based on weight. While simple, this isn't terribly accurate; not all objects have the same portion of their mass bound up in structure, and not all structures are equally strong.

I imagine that Gurps might at some point include rules for 'strong,' 'average,' and 'weak,' hulls. It looks like HP in Gurps Spaceships are based on 5x cube root of weight rather than 4x cube root of weight, for instance.

[David L Pulver]

Realistically speaking, you have several types of damage if using HP.

The version I have long wanted to use for GURPS splits the HP into two values: a "to kill" number and a "cumulative damage" number.

(1). HTK
This simulates the shot that penetrates armor and hits something important, taking it out. Studies of modern naval warfare in the missile age in which vessels that were lightly armored faced a single bomb or missile suggest that survivability scaled with the length of the vessel or the cube root of mass. This was also the basis of GURPS hit points. It reflects the odds of a shot, blow, etc. penetrating and hitting a vital part (brain, major organ, bone, etc.) whose strength is generally also scaled with overall length.

-> In humans, a hit to a vital organ, joint, etc.
-> In vehicles, a hit to an important part of a machine.
This probably scales roughly with length, and follows the GURPS formula.

For accuracy, this should probably be modeled as:
"Calculate HP normally, but it is then read as "HTK."
"Any time damage exceeds HTK/4, make a HT roll or be disabled. Modifiers: -1 if damage exceeds HTK/2, -2 if it exceeds HTK, -4 if it exceeds HTKx2, and -3 if the vehicle contains enough dangerous fuel or explosives to be volatile.

For most vehicles, assign a HT based on how well they're put together: attention paid to damage control, provision of firefighting gear, how tightly vulnerable components are packed, compartmentalization, etc., etc. Around 10-13 for average designs. That way you can simulate the difference between a russian and a US tank, for instance.

Targets that are utterly HOMOGENOUS ignore this result.

(2). Crew Casualties
Use the usual rules in 4e for penetrating the ship and taking out crews.

(3). Cumulative Damage.
Eventually, enough holes will kill anything, even a zombie or a wooden ship. Since GURPS damage is somewhat nonlinear, it's not fair to use weight directly - we'll have to scale it a bit. I suggest you assume HP = weight in lbs. (or 2,000 per ton) then find the linear measurement of SM, convert to yards, and divide by that value. Thus, humans (2 yards) have 150 HP have 75 HP; a 3,000 ton ship that is 150 yards long has 40,000 HP.

At 0 HP, start making HT rolls to avoid falling apart/keep going as usual. Modify this for ships at sea - as water will will be flooding etc.


Track damage separately for limbs etc. giving them proportionately HP.

(4). Surface Damage
For things like "how many surface weapon batteries/cannon/Traveller turrets: did I kill, probably assign them based on a fraction of the cumulative damage

[hal]

Hi Dave :)

I'm a wee bit confused when it comes to hit points in the example you used. I know I'm probably guilty of missing a rule somewhere or another (highly probable in fact!), but isn't the rules regarding hit points supposed to be something on the order of...

HP = (2000 lbs/ton x tons of vessel)^(1/3) x 4 if a complex vehicle or x8 if a simple vehicle?

The values you give for a human being at 75 hit points doesn't square with the average human having a ST 10 and HT 10, nor does the hit point tally for a 3,000 ton ship match what you suggest above with your alternative values.

I HAVE to be messing up somewhere - can you help?

[Rupert]

As I understand it, David is talking about a houserule he'd like to use someday.

[joelbf]

Originally Posted by Anthony

There are several problems here:

• Realistically, 'damage' is a function of the width and depth of the hole, relative to the dimensions of the target. GURPS handles the concept of 'width of hole' through the pi-/pi/pi+/pi++ figures, but ignores the second constraint of 'relative to the dimensions of the target'. Even without IT:Unliving, a SM +2 target should basically treat pi++ as pi, and a SM +4 target should treat pi++ as pi- (this is not easily generalized to other damage types).
• GURPS assigns hit points strictly based on weight. While simple, this isn't terribly accurate; not all objects have the same portion of their mass bound up in structure, and not all structures are equally strong.

The simple solution would be to come up with a guideline for assigning IT:Damage Reduction (Piercing) based on size and structural properties.

While David's post is enlightening, I personally feel it's too cumbersome for me.