WW1

[Skaran]

Totally forgot about the armour belts on these ships! So not just the guns but the arbitrary armour limits. In this regard I think the old TNE Fire,Fusion & Steel I might be better. If the armour can fit in the available space then it is acceptable. The limit then comes from trying to get everything else in.

Another thing that got broken was the machine guns, in Mongoose 1 the heavy machinegun was TL5 in Mongoose 2 it became TL6 which makes the Vanguard fighter a bit of a problem. Since the illustration was of a Mustang I used FF&S1 to reconstruct the machine gun carried by a P51 and came pretty close, a couple of kg overweight but damage in this system was higher at 8D.

Thought I have had,
1. Design the weapons in FF&S1 then adjust the damage.
2. Ignore the armour limit maximums. (If the armour can fit it can be carried)
3. Use something like High Guards prototype disadvantages for early TLs such as increased size and innacurate for a weapon of the same rating. Other things could be extrapolated as well such as 'short range' etc.

 

[Anonymous]

I still think misfire chance is a way to get more granulatity without additional record keeping. It's easier to remember if the gun is jammed, than its specific number of reload turns. It's realistic for pre-WW1 guns as well.

From VH page 35 we get max Protection of 10 for TL 3-5 (ignoring the fact that it is called "Iron" armour) with*3 for AFV (A Battleship must be an AFV) so max 30 Protection . Nowhere near enough for Royal Sovereign let alone Yamato.( A 1DD AP shell has 10 AP and does average damage of 35.)

Armor doesn't need to make it invulnerable. Reduced damage taken is fine.

A 14 kDt Royal Sovereign would be about 40 000 Spaces so has 160 000 Hull.

I didn't check this but it seems wrong. Those dtons of water (1m3) not (edit: Liquid) Hydrogen (14m3). Also the displacement of a water-ship is not equal to its volume. It's the volume of the submerged section only. You'll need to add the volume of the part above water to this. Apologies if the spaces turn out to be correct, but I think you can see why I asked.

 

[Skaran]

The Royal Sovereign with a total displacement of 14,150 long tons which is the weight of the water it displaces. This equates to an approximate volume of displaced water of 35 cubic feet (close enough to 1 cubic meter of water) per ton so the ship actually displaces (assuming 14 cubic meters of hydrogen equals one Traveller displacement ton) 14150 cubic meters of water or just over 1000 Traveller displacement tons. The actual total volume of the ship will be higher as a lot of superstructure is on top, but even doubling it you are looking at around 2000 displacement tons so 8000 spaces since 250kg gives 1 space. So about two thirds the size of a Midu Agasham class destroyer.

 

[Linwood]

Which makes for an interesting visual reference to Traveller ship sizes....

 

[Anonymous]

The Royal Sovereign with a total displacement of 14,150 long tons which is the weight of the water it displaces. This equates to an approximate volume of displaced water of 35 cubic feet (close enough to 1 cubic meter of water) per ton so the ship actually displaces (assuming 14 cubic meters of hydrogen equals one Traveller displacement ton) 14150 cubic meters of water or just over 1000 Traveller displacement tons. The actual total volume of the ship will be higher as a lot of superstructure is on top, but even doubling it you are looking at around 2000 displacement tons so 8000 spaces since 250kg gives 1 space. So about two thirds the size of a Midu Agasham class destroyer.

I don't have data for this specific ship, but the air/underwater volume ratio is much higher than the 1-1 you've used. The draft of this ship is given as 8.4 meters and her weather deck is about that above the water, plus the underwater parts are sloped and the draft is the maximum depth, not the average. If I had to guess I would say between 3-1 and 5-1 for this ship but that's just from eyeballing a photo of the parts above the waterline. I assumed something like a modern displacement hull, but I think older hulls might have been fatter underwater.

edit: The internet says this ship has 5.5 meters of freeboard (the distance from the waterline to the lowest point at which water can come in over the side, which is usually the weather deck (uppermost full deck exposed to the sky) but this ship might have some weird holes in the side for its sponson guns so it might be measured to much lower down than that on this ship).

edit: OK, this is ridiculous design.

. It is indeed a lot fatter underwater than I expected. You may well be right at 1-1. I would say not more than 2-1.

Source: Some Royal Museum, Greenwhich, London, UK. https://collections.rmg.co.uk/collections/objects/67177.html

 

[AnotherDilbert]

A 14 kDt Royal Sovereign would be about 40 000 Spaces so has 160 000 Hull.

I didn't check this but it seems wrong.

Yes, sorry that is wrong. By force of habit i wrote kDt when I meant ktonne.

1 Space = ¼ tonne = 250 kg. It's a mass not a volume.

The chassis mass does not include e.g. drives and fuel as those are abstracted, so I guessed that was about 4000 tonnes, leaving 10000 tonnes payload.

10000 tonnes = 40000 Spaces.

 

[Annatar Giftbringer]

Quite, but if we used 1DD+3 to model 1½DD (≈15D) it would be fair to give it AP 15 from AP ammunition?

It could be seen as fair, in a way.

On the other hand an autopistol and an assault rifle get the same benefits from AP as well, despite the pistol having -3 to its damage dice.

The issue (if there is one) gets clearer with destructive weapons since they multiply AP with 10, but overall we’d need to revisit the entire AP system (or make an exception for this particular weapon).

I’d be fine with a 1DD weapon and a 1DD+3 having the same AP benefits.

Agreed, the mechanism exists, but is barely used. See e.g. Black Powder Gun (CSC, p128).

Barely used doesn’t mean we couldn’t use it for a custom weapon if we want to

I might be mistaken here, but weren’t those cannons faster to fire than muskets? Partially due to them having a whole team of people dedicated to reloading them as opposed to the single infantryman responsible for his own musket, but IIRC cannons had proto-cartridges* before rifles got them, making them much faster to reload.

*no idea what they were called
In English, but in Swedish they were “geschwinda skott” after the German geschwind meaning fast. Basically blackpowder and bullet prepacked in a bag, ready to shove down the barrel.

Traveller is designed to be less detailed, and the default setting is the third imperium. I believe those two combined are part of the reason we don’t see more detailed and varied antique weapons. If anyone ever made an expansion or setting to recreate piracy in the Caribbean or the great Nordic war I’m sure we’d see more detailed weapons for this specific setting (like the WW II supplement(s?) Mongoose released for 1st edition).

3. Use something like High Guards prototype disadvantages for early TLs such as increased size and innacurate for a weapon of the same rating. Other things could be extrapolated as well such as 'short range' etc.

That’s an excellent idea! Using High Guard’s system of advantages and disadvantages on CSC weapons would make for a fun and flexible customization system! The current approach seems to be to create separate versions of gear with different TLs, which of course works too, but with a customization system we could design our own stuff.

On the other hand, CSC and VH feel a bit less rigid and more laid-back than HG, so it feels more ok to just create a new item based upon an existing entry.

 

[Jackstar]

What is not clear is how much of the turret is armour and how much the gun carriage.

Thanks.

We can guess, look at the German 38 cm (15") SK L/45 naval gun.
https://en.wikipedia.org/wiki/Langer_Max
It weighs 270 tonnes apparently including mobile land mount. This compares with the Bombardment Gun (CSC, p126) of 220 tonnes.

A fixed (but rotating) mount should be lighter?

I would set a WWI-II roughly 15" battleship gun at 2DD.
The lighter pre-dreadnought guns at 1DD - 1½DD.

For a comparison of the Furiuos (827 ton) and General Wolfe (384) turrets see
http://www.navweaps.com/Weapons/WNBR_18-40_mk1.php
This also gives ROF: Furiuos (1 per minute) and General Wolfe (1 per 2.6 to 4 minutes).

The same site gives informatino on the Royal Sovereign 13.5 in
http://www.navweaps.com/Weapons/WNBR_135-30_mk1.php
The most impotant is that it is in an open barbette mount.

Also see the Boche Buster 18 in railway gun
http://www.disused-stations.org.uk/features/index6.shtml

I think that is the CSC Heavy Bombardment Gun (3DD 500 tons - includes the wagon).
The D6 hours reloading is explained because it is a fully manual process, unlike the mechanised naval mounts.

So using that as a fixed point, i would use:
Heavy Cruiser, 8-10 in, 1DD
Battleship (including the Early Super Dreadnoughts), 11-14 in, 2DD
Advanced Super Dreadnoughts, 15-18 in 3DD

The old Royal Sovereign 13.5 in is at the bottom end of the Battleship (2DD) row. If you are using 1/2 DD then 1.5DD looks ok.

 

[AnotherDilbert]

For a comparison of the Furiuos (827 ton) and General Wolfe (384) turrets see
This also gives ROF: Furiuos (1 per minute) and General Wolfe (1 per 2.6 to 4 minutes).

I don't think a complete armoured turret is a fair comparison to a gun even with mount.

We know that a "normal" 15" battleship gun weighs about 100 tonnes naked, and a "maximum" 18" gun weighs about 150 tonnes.
15", 100 t: https://en.wikipedia.org/wiki/BL_15_inch_Mk_I_naval_gun
18", 150 t: https://en.wikipedia.org/wiki/BL_18_inch_Mk_I_naval_gun
18", 150 t: https://en.wikipedia.org/wiki/40_cm/45_Type_94_naval_gun

With the example of the Langer Max (38 cm SK L/45), an actual 15" naval gun (presumably ~100 tonnes naked) mounted in a railroad carriage that weighs a total of 270 tonnes with mount, we get an approximate factor of 2.7 from naked gun to complete mount.
https://en.wikipedia.org/wiki/Langer_Max

Given the same 2.7 factor a 18" gun would be ~400 tonnes with mount, still well short of the 500 tonnes of the Heavy Bombardment Gun.

500 tonnes with mount would be something like a 20"+ railroad gun. Hardly the normal BB armament.

Also see the Boche Buster 18 in railway gun
...
I think that is the CSC Heavy Bombardment Gun (3DD 500 tons - includes the wagon).

That is a tiny little howitzer of a mere 85 t naked (~240 ton with carriage?), definitely not the Heavy Bombardment Gun.

A howitzer is much lighter than a cannon, take the 20" french railroad howitzer:
https://en.wikipedia.org/wiki/Obusier_de_520_modèle_1916
20" howitzer, 260 tonnes with carriage, slightly lighter than the German 15" railroad cannon above.
Note that the range of ~15 km is much shorter than the CSC Bombardment Guns that are more in line with very heavy cannon.

 

[Jackstar]

Given the same 2.7 factor a 18" gun would be ~400 tonnes with mount, still well short of the 500 tonnes of the Heavy Bombardment Gun.

500 tonnes with mount would be something like a 20"+ railroad gun. Hardly the normal BB armament.

I agree that a factor of 2,7 seems reasonable.
21 in gun (experimental German 53 cm) are 335 tonnes
http://www.navweaps.com/Weapons/WNGER_21-52_gerat36.php
20 in gun (never built Japanese 51 cm) are 227 tonnes
http://www.navweaps.com/Weapons/WNJAP_20-45.php
With the factor of 2.7 gives 613 tonnes, near enough 500 for me,

So my scale was a little off. How about.

Heavy Cruiser, 8-10 in, 1DD
Battleship (including Dreadnoughts), 11-12 in, 1.5DD
Super Dreadnoughts 13.5-16 in 2DD
Advanced Super Dreadnoughts, 18 in, 2.5DD
Experimental, 20+ in, 3DD

Old (1880-1900?) get -0.5DD

 

[AnotherDilbert]

Heavy Cruiser, 8-10 in, 1DD
Battleship (including Dreadnoughts), 11-12 in, 1.5DD
Super Dreadnoughts 13.5-16 in 2DD
Advanced Super Dreadnoughts, 18 in, 2.5DD
Experimental, 20+ in, 3DD

Old (1880-1900?) get -0.5DD

Agreed, that sounds reasonable.

 

[Anonymous]

Careful with mount weights, or comparing mounted weapons between sea and land. Naval gun mounts will be significantly larger and heavier than land mounts. WW2 naval guns were usually stabilised, and must withstand rough seas and salt water. A railway gun mount is fragile in comparison and wouldn't be stabilized for moving fire.

edit: To give context about mount weight and durability for sea vs land - let's just say that UNarmored ship windows can be 5-10 cm thick (up to 4") to withstand the weight of water hitting them, and outboard motors should be flushed with fresh water immediately after every operation.

For modern naval guns, mount weight will typically include the ready rounds (and autoloader) - I'm not sure if ww1 or ww2 gun mount weights include ammo, but they probably don't have autoloaders.

 

[phavoc]

Naval guns and railway or coastal artillery guns conceptually only share gun tubes and shells. The design and manufacture of the guns (and ancillary things such as tube liners) were the same. Many coastal artillery batteries used surplus guns taken off older ships. Beyond that the comparison is pretty limited.

Naval guns, at least one the enclosed turret became the standard (prior to this larger naval guns were in somewhat shielded mounts with no overhead protection). Naval gun turrets mounted 2-4 weapons per turret, and often internally the guns had barriers between each gun because they were operated independently. Naval guns also had to deal with internal shell hoists and powder hoists for the guns. All of this had to fit within a very small area.

Coastal batteries varied between having cover or not, though most would have significant frontal protection such as stone parapets. Railway guns had no protection from enemy fire. The Paris guns the Germans used to shell Paris would never have made it on a ship. They were too long and too fragile for shipboard mounts. Plus they could only fire about 60 shells before they had to be returned to the factory to be re-bored. Naval guns of the era were wire-wrapped and could fire a few hundred rounds before they required servicing. There's a whole art and science to the building of naval guns.

There are some fabulous photo's of factories making battleship guns here - http://industrialscenery.blogspot.com/2016/11/building-and-testing-naval-guns.html

 

[Anonymous]

The ocean does it best to murder you and break your stuff even when it isn't trying.

 

[Condottiere]

1. Potentially, naval guns could be built to shoot further.

2. Smokeless powder helps visibility.

3. Better sighting and range finding equipment helps accuracy.

4. Computers help predicting fall of shot, which tends to vary due to flight time; even if they're hand cranked.

5. High velocity tends to shorten flight time, and minimizes trajectory; basically, point and click.

6. Higher rate of fire allows more overall weight to be delivered down range.

7. More turrets allow greater number of targets to be simultaneously engaged.

8. Bigger ships tend to be inherently more stabilized firing platforms.

 

[Anonymous]

8. Bigger ships tend to be inherently more stabilized firing platforms.

Yes and no.

While a small wave will affect the ship proportionally less, the deck being placed higher means it can move through a larger arc.

You also often see times when a small ship is much smaller than the distance between the wave peaks, and bobs up and down, while a larger ship gets "caught" by being lifted unevenly across a large portion of its hull, and will pitch or roll into and out of the trough. For large modern ships this can often happen when they have their sides to the sea (so don't do that, but sometimes you have to).

This one is hard to explain with words; imagine a rice grain on your finger. You lift your finger, it goes up and down. Now it's a pencil instead of a rice grain. it still goes up and down, but now it tilts as well.

I have no experience of the effect of naval gun recoil. This may be another factor in the equation.

This is really one of those "it depends" answers. Although I do see that you said "tend to be" (which is usually true) and not "always are".

 

[AndrewW]

You also often see times when a small ship is much smaller than the distance between the wave peaks, and bobs up and down, while a larger ship gets "caught" by being lifted unevenly across a large portion of its hull, and will pitch or roll into and out of the trough. For large modern ships this can often happen when they have their sides to the sea (so don't do that, but sometimes you have to).

Might need to in order to cross the T as an example.

 

[Condottiere]

Seems like crossing the A might be a better tactic, if you outnumber and outgun your opponents.

 

[phavoc]

Crossing the T (if you were the upper portion) was the best case to be in since you could bring your guns to bear while the enemy only had forward guns (this was only relevant after ship designers stopped placing guns that weren't centerline only).

One disadvantage to this was that as you were crossing the T, you had to present your entire ship to the enemy while in return you could only really target the forward section of the ship. And in the age of the torpedo you were quite vulnerable to torpedo fire. In the age of better fire control, off-bore missile launches, ECM, etc, being able to bring your energy weapons to bear would still have some applicability.

 

[AnotherDilbert]

I thought the point was that it was easier to hit when you crossed the enemies' T?

It's "easy" to point the guns in the right direction, but since the ship always rolls a little you generally miss more in length than direction. Hence a long, but narrow target was easier to hit.