MTBs and Torpedoes

[maddox]

For WWI even a 67% damaging hit chance is on the generous side.   Also, there are reports of ships taking a lot more torpedo hits than anybody would believe and still were recoverable. 

Maybe using a wider damage spread? From nearly nothing to normal damage with a golden BB hit even more rare.

[Kaiser Kirk]

I do a second roll for where on the ship it's hit. Bow and stern may flood, but so long as 65% of the ship has flotation, I expect extra torpedos in the bow/stern ..just flood already flooded areas.

That means first I halve the chance of a hit, then after a torpedo hits there's a roughly 51% chance it won't be going off in the raft/body section of the ship.
That seems a pretty good fudge downwards, and why a number of Japanese vessels survived.

I also use the Springsharp # of torpedoes as a guide for how many that ship can take. Since these are early torpedoes, I presume it takes a few more to "count'

SK4 does have a bit of a variable damage from less than standard to more than standard, but it's meant for generic "Damage Points" not specifically designed ships.

I will point out that so far the "battleships" lost have all been 1890s 15000t or less.
Only 1 ship had any torpedo defenses, and that was the Chinese (Norse) cruiser caught at anchor with her nets out - who simply took a minor bow hit. The other 4 got caught on the nets.

These are pretty much all old heavy cruiser sized vessels, or smaller, hit with multiple torpedoes launched at point blank (2-3km) range.
I'm really not sure it's a great sample to use.

[Desertfox]

I think damage caused and did rate is not the main problem, accuracy is. The hit rates are very high for the distances involved. The Chinese torpedoes were launched at nearly 5 kms. While in OTL the Japanese at Tsushima were launching torpedoes under 500m at stationary targets and still missing alot more. The other example is the US PT boats at Suriago Strait, they had the advantage of radar and an enemy caught in a narrow strait and failed to hit anything.

[Kaiser Kirk]

I think this subject is worth splitting off and discussing specifically.
I really don't want a naval warfare game where we are all building torpedo delivery systems as the killer app.
I'm happy to depart "reality" to achieve that, but that choice is not mine to make.

I use SK4 because..well I have it. 
Plus it's actually pretty robust
I knew there were some issues, from solo exercises I played ages ago.
I remember Secondary common rounds critting FC as a particular issue.
Torps ...I just remember being complex.
Therefore I wanted to refresh myself, and figure out some fixes.

So it was my intent to find some down time to playtest SK4 before we launched into wars,
but that really hasn't happened as we quickly went into the Sino-Japanese war long before I got to that point.
Which means it's the best I have and I have made changes as I go.

A notable one rolled out this set of battles, is for every 1000m below "max" FC range, there is a +1.  This has been helping both sides.
I had considered +2, and may do that in the future, which would increase the ability to "swat" MTBs.

I afford 1905 torps ~4000m range, and 1908 torps ~6000m range, making launches about 1000m inside that desirable as ships can't run away.

As noted Hit Rates have been high.
I have generally attributed that to the very short range, and often times cross fire as drastically effecting the "To hit" percentage.

Rates early on drastically exceeded expectations, and historical precedent, which lead to my applying the modifiers.
During the Sino-Japanese I was tracking hit expectation vs. hits, and there was a higher rate than expected.
That continued in this one...not sure what to do about an on-line dice roller hitting more often than expected.

As I've said, I've considered applying a fire control penalty on top of the SK4 formula, which would penalize MTBS.
But again, I have not had time to game that out and find what is reasonable.

The formula SK4 uses is :
(((57.3 * target length (ft) * Singe of Angle of Bearing from target)/ Range in feet ) / 'Relative Tracking Error'

The result then gets compared to Chart T.4, where a '0.44' becomes 34%.

The SINE is a little tricky, but I generally have counters on the rug, and so can estimate the angle. The ships turn as best possible to minimize the angle of most torps.
The presence of Range as a divisor means it has a fairly heavy effect on hit rates.  I would like to change that to a TIME aspect, so torpedo speed matters..but ...time.
The 'Relative Tracking Error' is based on the target speed, and then modifiers for such things as zig-zagging, EM, combing spread etc, and so reduces it more.

All and all it's rather unclear why the numbers are what they are. But it *seems* like they cover the variables.

For Example :
IRS Sublimis was launched on from two directions, she tried to minimize the chance from the bigger group, which left a bigger target to the other.
Hitting a 426ft long IRS Sublimis from 40degrees astern at 2000m.  ( two sets of launches, so different angles)
57.3 x 426 x 0.643 = 15695
divide by range = /6000 = 2.62
Sublimis was going 18knots and was combing the other set, so only RTE of 7 = /7 = 0.38
0.38 on the chart becomes 30% "Torpedo Hit Probability"
Which I divided by 2 as my own "fix"
To 15%

Now, if the launch had been at 8000m,
the TH % would be : 6%, halved to 3%.   Which is close to the right rate.
And that's a quarter shot on a slow, fairly large target, at what is still a close range.

Then the Online Dice roller hit multiple times.
Rolling for location, I got citadel hits.

That gave the Sublimis 4 hits (1 stern, 3 citadel) on a 14,500t ship that can take 2.6 hits.
A torpedo strike that successfully gets past the TDS (none) does a belt crit.
2 magazine hits and I think a flooding of engine spaces.
Sounds fatal to me.

So... where do I put the thumb on the scale?

I want folks to be comfortable with how we do these things,
and frankly I'd be fine if the gun reigned supreme, if anything I'm trying NOT to push my preferences on the rest of you.

[TacCovert4]

I'm fine with the gun remaining supreme in the end.

However, considering the particular era, and the type of battles, I think that MTBs aren't necessarily OP.

The two wars that have been MTB orgies have been island or other confined waters campaigns.  The ideal MTB territory.  And mostly MTBs have been used in mass attacks over 30 boats.  In those cases 60+ torpedoes potentially being fired is going to be disgusting.

Overall, I might offer two suggestions:

1)  Scaling the torpedo accuracy of MTBs by size/era.  One could presume that torpedo aiming systems are going to be more accurate on later and bigger MTBs.  Also, firing a 3t torpedo from a 20t vessel is going to cause some pitching and such and especially at speed could affect general precision.

2)  Scaling the FC for secondary guns by FC era, or denoting additional secondary directors.  For instance Sublimis was smacking around every MTB it hit....but it could only use its full FC on one at a time.  I think that this creates the situation where it's reasonable for someone to add in the additional tonnage for dedicated secondary directors.  Additionally or Alternatively, for each upgrade of FC add .5 to the + number for MTBs getting closer.  I think it's reasonable that in the 1905-1915 decade.....MTBs could maul the crap out of ships that aren't heavily escorted by DDs.  But in 1920?  By then MTBs getting close enough to get guaranteed hits in daylight......are just asking to be squad-wiped en masse.

[Kaiser Kirk]

As a point of information,
I have frequently been allowing "Capital Ship" architecture to engage 2 targets at once with the primary/secondary.
For the Imperito class, they only have 5 x 140mm on broadside, so I kept it to 1 target for higher chance of one hit.
It is an admittedly fuzzy thing.

I'll defer from discussing the other points as I don't want to seem like I'm jumping on each topic,
and I'm trying to do the background prep for the Battle of the Caicos.

[TacCovert4]

As a point of information,
I have frequently been allowing "Capital Ship" architecture to engage 2 targets at once with the primary/secondary.
For the Imperito class, they only have 5 x 140mm on broadside, so I kept it to 1 target for higher chance of one hit.
It is an admittedly fuzzy thing.

I'll defer from discussing the other points as I don't want to seem like I'm jumping on each topic,
and I'm trying to do the background prep for the Battle of the Caicos.

Good to go. Makes sense.

Battle of the Caicos II, Electric Drive Boogaloo

[snip]

Indeed, as there are electric drive ships there this time.

[snip]

Having thought on this overnight, I think the heavy lean into the torpedo and its smaller delivery platforms is a function of a couple things. First, we are seeing conflict arise around amphibious landings a lot more than we have at this point in OTL. This is putting ships in more static areas where the reduced ranges of these craft does not tend to matter as much. I see this trend continuing as there are only a handful of places outside of Europe that this will not be the case. Second, so far we have not had a lot of modern ships in play. The older ships cant take this as well, but this is also something I see continuing as torpedo protection is going to outpace the TDS's that exist on anything short of the most modern ships. Third, the better results have been at night against ships without good night fighting equipment. I know that's an area that Rome has some major catching up to do. I think that also has a part to play in the close ranges. Ultimately, I think there are a couple IC counters that can come into play (leaving the implementation of any combat adjustments to Kirk, since he as a much better practical understanding of those factors). First is more ubiquitous night fighting equipment to facilitate nighttime engagements. Second is a larger focus on screening ships to push out the range of "secondaries" to keep the lighter torpedo craft further away from capital units. For example at Grand Turk I only had two cruisers, that should have at least been tripled or supplemented by larger destroyers. Third, keep capitals ships away from that sort of environment (I think we may be getting the best lesson yet about that Soon(tm) at my expense) and if you cant they need to be more suited for the task then a pre-dread.

[Kaiser Kirk]

A couple notes
A) the star shell will help night fighting by extending ranges. It's still very hard to hit an MTB at 14km.

B) Gunlines advanced towards the MTBs are very useful.

C1) The original name of 'destroyers' was 'torpedo boat destroyers'. They were the small light gun platforms expected to hunt and kill the TB swarms.

C2 ) Had the Romans more cruisers/destroyers at Grand Turk, likely very different.

D) I've been unsure how 'realistic' forces moving around at night ARE...but we do have a tech for it, and if there's moonlight and a plan, it seems workable.
As I described for the Chinese, three pairs of bullseye lanterns mounted would allow ships astern, or port/starboard quarter to keep their position and distance.
The primary problem would be finding your target, but folks have been conveniently anchoring so they can be found. I also limit speed for most of the transit, to make keeping place easier.

E) Fox pointed out the 5000m ranges on some Chinese launches. They had 1908 tech, and on the early Japan battles, there was no To hit modifier on the TORPs,but during that war I started reducing it by 1/3 and then by 1/2.

F) The one heavy screen was the Japanese. Lack of fire control severely limited it, but it still chewed up and spit out a large number of MTBs. It was really the 3rd wave, of destroyers, from a new direction, that drove some home.