Wet Navy Combat Damage

[Josh77]

So, my current Traveller campaign may soon involve some surface and subsurface naval warfare on a TL8 world. Looking at the absurdly high amount of hull points vs the relatively tiny amount of damage aTL8 torpedo could do, I saw that it would take a crazy number of torpedoes to sink something like the Achilles class frigate in the Vehicle Handbook. I figured in the real world a modern torpedo could possibly sink a frigate size vessel in a single well placed hit, and certainly with 2 or 3 torpedoes. Here are the house rules I came up with for naval warfare damage:

Wet Navy Combat
Naval vessels have “waterline damage” points (WDP).

W=T(H/50,000)

Where W=waterline damage points (WDP), T=Tech level, and H=hull points. Round fractions up.

When a water vessel takes damage from a DESTRUCTIVE weapon, roll an additional d6. If the result is a 6, waterline damage has been done. Note that if the weapon is a torpedo, or the target is a submersible, the roll is not needed and is always considered to have inflicted waterline damage. Whether or not WDP are inflicted, regular damage is still applied. A ship may end up dead in the water before it starts sinking from regular damage.
If waterline damage has been inflicted, damage is rolled as normal. Any damage dice that rolled a 6 results in a point of waterline damage. When a vessel has been reduced to zero WDP, it is sinking. If the damage done is equal to the vessel’s WDP, it will sink in 1d6 hours. If the WDP has been exceeded, it will sink in 1d6x10 minutes. If the WDP have been doubled, it will sink in 1d6 minutes.
For example, the Achilles class frigate is TL9 and has 14,000 hull points. This comes out to 2.52 WDP, rounded up to 3. The frigate is hit with a heavy cannon that inflicts 2DD damage. A d6 is then rolled to see if a waterline hit was scored. If a 6 is rolled and then when damage is rolled if either dice comes up as a 6, 1 WDP has been inflicted. If both dice roll a 6, 2 WDP have been inflicted.
If the same ship was hit with a TL8 torpedo (5DD damage), it would automatically have a chance to inflict waterline damage. Any of the dice rolled for damage that scored a 6 would inflict a point of waterline damage. A single TL8 torpedo could possibly sink the frigate, though it would likely take 2 or 3 torpedoes to do the job.

What do you guys think? Looking through my old Twilight 2000 v2.2 rules gave me the idea for waterline damage. Anything not hitting the waterline of a naval vessel would still take forever to wear it down, but well placed shots can send a ship quickly to a watery grave. I could also see maybe giving missiles that are specifically anti ship a better chance to inflict WDP damage. I'm looking forward to any feedback!

 

[Condottiere]

I would think that if enough water enters, it will sink, regardless of actual amount of damage a torpedo has caused.

And if it's contained on one side, but compromised enough bulkheads, it could capsize.

 

[Josh77]

Right, and that is what I am trying to model with this. That's why it is kind of random, but based on the damage dice inflicted. That is also why I had TL affect it. I figure higher TL would have better ability to compartmentalize and counter flooding. But I also wanted to keep it simple. I think modeling what side the ship is listing to would start to get too much. I just want a system that gives a plausible result, not with frigates that can survive being hit by 200 torpedoes, lol.

 

[Tupper]

Here are some thoughts (three possible approaches):

As the MgT2e system stands, there are a three things going on:

1. Wet navy ships have a capped armour level. So they're always going to take quite a bit of damage from destructive hits (although, as you note, they can take *a lot* of hits).

2. Torpedoes are smart and do destructive damage.

3. The amount of damage you need to do successive levels of criticals *doesn't* increase as your vehicles' hits go up. Do 60 points of damage, and you've got yourself a level 6 critical. Do 200, and you've got yourself a level 6 critical, and 14 criticals to spare, which would be 14*6D = 84D = an extra 294 damage.

So... my thinking is that the elegant fix for the problem would be to enable criticals to sink the ship. Looking to TNE's combat rules (which evolved from Twilight 2000/Space 1889), they replace a suspension hit with a waterline hit. So you might get some mileage out of rewriting criticals for the "drive system" as waterline hits. Torpedoes are pretty much always going to score level 6 criticals, so if the level 6 critical sinks the ship, you'll get your fatality (although only one in 12 hits will be a waterline hit).

The appeal of this approach is that you're not adding extra dice rolls, but are letting the existing critical system to work for you.

Alternatively, if you look back to the MgT1e system, they suggested handling "big" ships as having multiple sections, each with their own hits. Once a section takes half damage, it starts to flood. Once a quarter of the sections have flooded, the ship sinks. So that could see you sinking a ship with only doing 1/8 of its hits (or 1750 damage for a 14,000 hit ship). This might take 10 torpedoes or so (less with criticals). Alternatively, completely destroying a section causes the ship to sink. So if a ship has 14,000 hits, and is divided into 70 sections, each with 200 hits, you could see a torpedo destroying a section and sinking the ship.
Alternatively, make it 35 sections, with 400 hits, and you'd probably need a critical hit to destroy one.

As a closing thought, I do wonder if hull criticals should do some kind of proportional damage. For example, a hull critical for X damage does X damage or X% of the vehicle/starship's total hits. That way if you get a level 6 hull critical and roll 30, you've just toasted 30% of the ship's hits (or 30 hits for small ships).

 

[Josh77]

I like your ideas! I'm going to start messing around with those and see if I can find something we feel works well. Thanks for the input!

 

[Rikki Tikki Traveller]

I like you idea, but what if you just eliminate the need for the 1D6 roll to see if WDP damage is possible.

Just let every 6 by a DD weapon cause WDP damage. Maybe torpedoes or submerged weapons do WDP on a 5 or 6?

Reduces the number of dice you need to roll.

 

[dagrillac]

So, my current Traveller campaign may soon involve some surface and subsurface naval warfare on a TL8 world. Looking at the absurdly high amount of hull points vs the relatively tiny amount of damage aTL8 torpedo could do, I saw that it would take a crazy number of torpedoes to sink something like the Achilles class frigate in the Vehicle Handbook. I figured in the real world a modern torpedo could possibly sink a frigate size vessel in a single well placed hit, and certainly with 2 or 3 torpedoes. Here are the house rules I came up with for naval warfare damage:

Hi,

I have been reading about the battle of the Atlantic and merchant ships hit by torpedo's were not automatically sunk. I have read of several instances in a single convoy where the ship was hit, the crew abandoned ship and refused to return, so the escorts had a go at them with pop guns and depth charges and later on another u-boat would turn up find the ship still afloat and stick another torpedo in.

To me you need to consider crew morale more than anything, I also vaguely remember (from reading about 50 years ago) the us tanker Ohio making a run to Malta with huge damage.

Regards

David

 

[capnhayes]

https://youtu.be/7vaImLvZbPw

 

[capnhayes]

This link gives an example of a ship getting taken out by a Mk 48 Torpedo (TL 7 Torpedo)... This vividly shows why the rules were lacking and need some adjustments.