House Rule - Carronades

[David Manley]

Chaps, the lack of carronades in the rules has been mentioned here and elsewhere. I thought I'd draft a simple set of additional rules to cover them. Here's a starting suggestion:


Shooting at long range (yellow) - no additional effect


Shooting at medium range (orange) - draw "A" damage chits equal to 1/3 gunnery rounded up in addition to normal damage


Shooting at short range (Red/Purple) - draw "B" damage chits equal to 1/3 gunnery rounded up in addition to normal damage

Comments welcomed :)

[fredmiracle]

Everything I know about carronades is what I vaguely recall from the issue of S&T containing Fighting Sail that I received at roughly age 11. But didn't mounting carronades involve a tradeoff--giving up longer range firepower to get more throwweight close in?

[David Manley]

Everything I know about carronades is what I vaguely recall from the issue of S&T containing Fighting Sail that I received at roughly age 11. But didn't mounting carronades involve a tradeoff--giving up longer range firepower to get more throwweight close in?

Not in most cases. Carronades weren't counted as part of the standard ship fit, which is why you see 38 gun frigates mounting 40+ guns, as they shipped extra carronades. They were also lighter than equivalent long guns and were mounted on slides rather than wheeled carriages so they were easier to fit in areas less useful for more traditional pieces.

Some ships though did land all their long guns to give themselves an extremely heavy short range punch. Obviously in these cases there was a penalty in terms of ineffectiveness (sometimes total) at longer ranges.

[Diamondback]

ISTR that over-carronading contributed to the taking of USS Essex...

This ties in with an idea I had for "ship upgrade" cards--how would we value an extra 4 carronades on, say, a 32 vs. on a 74?

[The Mad Hatter]

Not sure what my opinion is on what the actual rules should be, but I do feel we do need rules for carronades. They add quite a bit of difference to the way a battle would be fought - do I have a ship that's heavily cannon armed or do I have a significant number of carronades? Tactically I think it would add a lot the game as the carronade ship would be deadly at close range where the weight of shot could just devastate the enemy, while the enemy works to try to stay at longer range to maximize the use of his long guns. Based on my limited playing thus far, I think it'd change a lot of the dynamics of movement and game tactics.

Just my two cents - have to think more about what I think the rules should look like.

[Andy Blozinski]

If you're trying to simulate a ship that had a handful of carronades to supplement the cannons already there, it's possible that is already included in the different damage chits for range. Ares could verify this. If you're trying to simulate a ship whose primary armament is carronades, then a ship card similar to the captain/crew deck cards would be the best way to implement.

[David Manley]

I'm fairly sure they aren't. The difference between those with and those without certainly isn't.

I've found the carronade question to be particularly relevant in campaigns. We've runa few in the past where some players have gone carronade crazy and sought any opportunity to rearm their ships, maybe reading too much on the career of the Essex. sometimes its paid off, sometimes it ended as it did for Essex, with an unbalanced armament against someone with longer arms. But it did add something to the campaign, and to the uncertainty when going up against what appeared to be a regular '36 but might not be.....

Whatever we come up with a simple rule addition on a card in the same way as the captain and crew ability cards is probably the thing to aim for. it works well for weapon upgrades in X Wing

[Пилот]

Mayby simple table, something like

0 - 4, no effect
5 - 8, 1 extra counter for full broadside, otherwise no effect
9 - 12, 2 extra counter for full broadside, otherwise 1 counter

or something similar (this is just example)

And about decreasing of fire power due to losses": each loss would decrease fire power for one level (9-12 becomes 5-8 etc.)

[The Mad Hatter]

Since I don't have my copy, I can't look at the damage chits, but here's my take.

A ship that has significant carronades (i.e. something that has been armed with 18 cannons and 30 carronades, not a ship with 4 carronades) - you do something like minus one chit at long range, plus one chit at short range. If you really wanted to create more difference, you could do minus two at long range, plus two at short - even halve the long range and double the short if you really wanted. To me, that's the easiest way to do this.

Alternatively you could look at the difference between the chits in A versus B etc. You could even say carronades use a more potent chit level, but only operate at short range. I.e. a ship that has 2/3/2 would use one set of chits for long range damage (a lower damaging chit set) and the highest damaging chit set at short range.

In my mind, keeping it as simple as possible is key. Since the different chits with different loads/ranges are already integral to the game, I'd look there for the solution. Either number of chits or type of chits.

[csadn]

And for fans of the Russians, there's this freaky beast, the "edinorog" (unicorn): http://digitalgallery.nypl.org/nypld...&pNum=&pos=156 ....

[David Manley]

Yes, but its another weapon that spectacularly failed to make any impression on naval warfare until more developed forms appeared a few decades later (and even then their effects have been rather overstated)

[Coog]

I would be interested in knowing how the firepower factors for ships were determined to start with, particularly how carronades were figured into the equation. Not having my order yet and being able to have a good look at the game, I'm not sure of how everything balances out. The game may be way too simplified to adjust for gun range and type differences.

[The Royal Hajj]

David probably has the most experience in this area with both the armament and the game. But I think the range in this game might be to short to effectively differentiate the cannon and carronade ships?

[csadn]

David probably has the most experience in this area with both the armament and the game. But I think the range in this game might be to short to effectively differentiate the cannon and carronade ships?

Given the vagueness of scale in the game (the ships may be 1/1000, but we have no idea how long a turn is), it's hard to tell what ranges actually are. However, cannon fire was generally ineffective past about 200 yards -- not because the cannon couldn't reach, but because aiming tech was near to nonexistent (and coupled to the fact that both gunner and target are moving three-dimensionally...), so really, "range" should be more a matter of "can the gunner hit" rather than "how far does the shot go".

[David Manley]

Given the vagueness of scale in the game (the ships may be 1/1000, but we have no idea how long a turn is), it's hard to tell what ranges actually are. However, cannon fire was generally ineffective past about 200 yards -- not because the cannon couldn't reach, but because aiming tech was near to nonexistent (and coupled to the fact that both gunner and target are moving three-dimensionally...), so really, "range" should be more a matter of "can the gunner hit" rather than "how far does the shot go".

Maximum range was in the region of 2k-3k yards. Typical effective engagement distances started at about half that, but obviously there was a keenness to bring the range down to "point blank" or less

[csadn]

Maximum range was in the region of 2k-3k yards. Typical effective engagement distances started at about half that, but obviously there was a keenness to bring the range down to "point blank" or less

That was my point -- as noted in the _Constitution_/_Java_ fracas, Bainbridge let one rip at half-a-mile away (880 yards), and accomplished Nothing. Most accounts of battles, the fighting is maybe 25-50 yards apart, because the inadequacies of targeting made scoring hits much farther out almost impossible.

<- looks at the ever-growing tangle of complication, and wonders if it's really worth bothering

[Coog]

That was my point -- as noted in the _Constitution_/_Java_ fracas, Bainbridge let one rip at half-a-mile away (880 yards), and accomplished Nothing. Most accounts of battles, the fighting is maybe 25-50 yards apart, because the inadequacies of targeting made scoring hits much farther out almost impossible.

But it did occur...USS United States vs HMS Macedonian...and as far as Bainbridge goes, we've discussed his competence before.

<- looks at the ever-growing tangle of complication, and wonders if it's really worth bothering

It may be just easier to replace the whole gunnery system with something home grown.

[DeRuyter]

IMO any campaign or scenario for 1812 lake battles needs specific rules for carronades. Many of the smaller ships, brigs in particular were armed primarily with carronades. Also as was previously mentioned, the USS Essex and an earlier SoL example would be the HMS Glatton (Cpt Bligh in command!).

A prime example of a game effect would be Lake Erie, where the American's being primarily carronade armed had to close the range with the British line while under fire from their long guns. A good play test start might be to exclude long range shots (except bow chasers) from ships armed primarily with carronades.

Eric

[Coog]

I think I would have firepower numbers for each range based on number of guns for that range. Something like long range for larger long guns only, let's say 12 pounders and larger, medium range for smaller long guns such as 6 and 9 pounders, and short range for carronades. Damage chits would be based on gun size.

[The Royal Hajj]

My thinking was more along the lines that if we decide that range should be a stat for the carronades, is there enough difference between the current ranges to make that a viable option?

In game turns, how often are we going to be at long range where carronades (if we limit them to half rang and less) are out of range but the long cannon ships can still effectively attack? In almost all of the games I've seen, the ships end up in close range for 90% of the fighting, or even stuck yard arm to yard arm.

At what point in the Age of Sail did carronades supersede regular cannons?

[DeRuyter]

My thinking was more along the lines that if we decide that range should be a stat for the carronades, is there enough difference between the current ranges to make that a viable option?

In game turns, how often are we going to be at long range where carronades (if we limit them to half rang and less) are out of range but the long cannon ships can still effectively attack? In almost all of the games I've seen, the ships end up in close range for 90% of the fighting, or even stuck yard arm to yard arm.

At what point in the Age of Sail did carronades supersede regular cannons?

I don't think they ever superseded long guns, rather for larger ships added to the broadside throw weight at close range. Also since they were smaller and lighter they could be mounted higher on the ship, ie; Victory's 68 lb smasher. For smaller (unrated) ships the advantage was the ability to place much heavier weight on the broadside than could be done with long guns. The penalty was in lack of "effective" range.

I think if the Captain knew his opponent was primarily armed with carronades then he could stand off at long range, which is what happened with the USS Essex.

Eric

[csadn]

At what point in the Age of Sail did carronades supersede regular cannons?

Never -- in fact, as tech advanced, the emphasis was on ever-longer-ranged guns. The problem was not "could the cannon reach"; the problem was "could the gunners hit the target".

[Coog]

My thinking was more along the lines that if we decide that range should be a stat for the carronades, is there enough difference between the current ranges to make that a viable option?

In game turns, how often are we going to be at long range where carronades (if we limit them to half rang and less) are out of range but the long cannon ships can still effectively attack? In almost all of the games I've seen, the ships end up in close range for 90% of the fighting, or even stuck yard arm to yard arm.

At what point in the Age of Sail did carronades supersede regular cannons?

I think once everyone gets the hang of the movement system and maneuvering their ships better, we could see situations where range would make a difference. I have played in games using other systems where I kept my distance to take advantage of having guns with longer ranges and it does work quite effectively.

I don't know if trying to tinker with the existing SOG combat system would be workable as it might throw the system out of balance. SOG, like WOG, was designed to be a simple game and in doing so gives up detail for simplicity. For those times a more detailed game is desired, we might have to just play a different game.

[David Manley]

I don't know if trying to tinker with the existing SOG combat system would be workable as it might throw the system out of balance. SOG, like WOG, was designed to be a simple game and in doing so gives up detail for simplicity. For those times a more detailed game is desired, we might have to just play a different game.

for an age of sail game SGN combines an interesting mix of complexity and simplicity. Crew management for example is at the higher end of the complexity scale for an Aos set of rules, yet the gunnery system is remarkably simple and coarse in its coverage. It really is a very interesting combination. that coarseness in the gunnery system opens up many possibilities for modification to develop an expanded system for actions involving only frigates and smaller ships.

[Berthier]

for an age of sail game SGN combines an interesting mix of complexity and simplicity. Crew management for example is at the higher end of the complexity scale for an Aos set of rules, yet the gunnery system is remarkably simple and coarse in its coverage. It really is a very interesting combination. that coarseness in the gunnery system opens up many possibilities for modification to develop an expanded system for actions involving only frigates and smaller ships.

David are you suggesting the "coarseness" in the gunnery system is a deliberate design intent to allow for later modification, or that's the way it is and it just happens to be amenable to modification?

ie Did you let slip future release information

[David Manley]

David are you suggesting the "coarseness" in the gunnery system is a deliberate design intent to allow for later modification, or that's the way it is and it just happens to be amenable to modification?

ie Did you let slip future release information

No, the coarseness I'm referring to is in the lack of range in broadside factors that makes it difficult to reflect differences between ships, in particular at the smaller end of the scale. For example, we have the Amazon (32 gun, 12pdr with a Burden of 2, BS of 4), Concorde (32 gun, 12pdr with a burden of 3, BS of 3).

So how do we reflect a 36, 38, 40, or a 44, or a 50, or a 64? Or the difference between a 32 gun frigate with 12pdrs and one with 18pdrs? Between our 32 gun 12pdr frigate (BS4) and our 74 gun SOL (BS6) we have not a lot of scope to split out variations in gunnery so the "buckets" into which frigate and small SOL firepower is going to have to be placed will have to be pretty broad (I'm guessing up to 38s and 40s will have a BS of 4, 44s and 64s a BS of 5, so your Africa / Constitution matchup will probably be just that, at least in terms of firepower).

But what I'm suggesting is that one could put together a very nice small ship variant where (for example) a 24pdr 44 could have a BS of say 8 and a burden of 6, down to a 9pdr 14 gun sloop with a BS of 2 and a burden of 2, and then place other ship types in between with appropriately scaled BS and burden factors. so maybe a 36 gun 18pdr would have a BS of 6 and a burden of 5, whereas a 12pdr equipped ship might be 5 and 5, whilst a small 24 gun 12pdr might be 4 and 4. These are just illustrative numbers, I've not done any calcs to see if they work well but hopefully you get the idea.

[fredmiracle]

Sorry to ask the stupid question, but just to double-check, I presume it has been confirmed that none of the models in the first wave carried carronades at the time they are portrayed?

[DeRuyter]

Sorry to ask the stupid question, but just to double-check, I presume it has been confirmed that none of the models in the first wave carried carronades at the time they are portrayed?

Several folks may have researched those ships in particular, it is possible but may be unlikely on the earlier British ships. See this Wikipedia excerpt:

Carronades initially became popular on British merchant ships during the American Revolutionary War. A lightweight gun that needed only a small gun crew and was devastating at short range was a weapon well suited to defending merchant ships against French and American privateers. In the Action of 4 September 1782, the impact of a single carronade broadside fired at close range by the frigate HMS Rainbow under Henry Trollope caused a wounded French captain to capitulate and surrender the Hebe after a short fight.[4]

The Royal Navy was initially reluctant to adopt the guns, mainly due to mistrust of the Carron Company, which had developed a reputation for incompetence and commercial sharp practice.[5] Carronades were not even counted in numbering the guns of a ship. It was Lord Sandwich who eventually started mounting them in place of the light guns on the forecastle and quarterdeck of ships. They soon proved their effectiveness in battle. French gun foundries were unable to produce equivalents for twenty years,[5] so carronades gave British warships a significant tactical advantage during the latter part of the 18th century — though French ships mounted another type of weapon in the same role, the obusier de vaisseau. HMS Victory used the two 68-pounder carronades which she carried on her forecastle to great effect at the Battle of Trafalgar, clearing the gun deck of the Bucentaure by firing a round shot and a keg of 500 musket balls through the Bucentaure's stern windows.

The carronade was initially very successful and widely adopted, and a few experimental ships (for example, HMS Glatton and HMS Rainbow[5]) were fitted with a carronade-only armament. Glatton, a fourth-rate ship with 56 guns, had a more destructive broadside than HMS Victory, a first-rate ship with 100 guns. Although Glatton and Rainbow were both successful in battle, the carronade's lack of range against an opponent who could keep well clear and still use his long guns was an arguable tactical disadvantage of this arrangement.

In the 1810s and 1820s, tactics started to place a greater emphasis on the accuracy of long-range gunfire, and less on the weight of a broadside. Indeed, Captain David Porter of USS Essex complained when the navy replaced his 12-pounder long guns with 32-pounder carronades. The carronade disappeared from the Royal Navy from the 1850s after the development of steel-jacketed cannon by William George Armstrong and Joseph Whitworth. Carronades were nevertheless still used in the American Civil War in the 1860s. The last known use of a carronade in conflict was during the First Boer War. In the siege of Potchefstroom the Boers used 'Ou Griet', an antique carronade mounted on a wagon axle, against the British fort.[6]

http://en.wikipedia.org/wiki/Carronade

Interesting bit about the English suspicions of the foundry.

[The Royal Hajj]

Okay, I did not think they ever replaced them... so my thoughts would be that they should only be fired at C/D range and use added counters from either the A or B set. Perhaps an easy solution would be to add the current fore/aft number to the standard fire power being dealt by the ship.

So, if we take an undamaged Commerce De Bordeaux, it has a 4-7-4 fire power, a long range full broadside would throw 7 A counters. At short range (should we call this special range since all the ammo there is considered special?) it would throw the 7 for the full broadside and 4 extra B counters (if we decide on B) for the carronades? After taking four boxes of damage, it would throw 5 for the full broadside and an extra 3 for the carronades. This would simplify balancing how many of each type was destroyed as the ship took damage. I would also be ease to add up how many counters you deal out.

[Andy Blozinski]

Okay, I did not think they ever replaced them... so my thoughts would be that they should only be fired at C/D range and use added counters from either the A or B set. Perhaps an easy solution would be to add the current fore/aft number to the standard fire power being dealt by the ship.

So, if we take an undamaged Commerce De Bordeaux, it has a 4-7-4 fire power, a long range full broadside would throw 7 A counters. At short range (should we call this special range since all the ammo there is considered special?) it would throw the 7 for the full broadside and 4 extra B counters (if we decide on B) for the carronades? After taking four boxes of damage, it would throw 5 for the full broadside and an extra 3 for the carronades. This would simplify balancing how many of each type was destroyed as the ship took damage. I would also be ease to add up how many counters you deal out.

I kind of like that kind of thinking for a reference, but.....
Ya know...on a stern rake that's (17) B counters. We need to be careful not to get too carried away with this stuff.

[The Royal Hajj]

Yes, rakes could be a problem... but than we can just say that the carronades don't get the extra "rake" counters.

[The Royal Hajj]

Yes, rakes could be a problem... but than we can just say that the carronades don't get the extra "rake" counters.

A simpler way to state this would be: Carronades damage counters are add after all other modifiers. Also, because of the ranking rules (well, mainly because of them) I think carronade damage should be drawn from the A set regardless of range they are shot at. We don't want to make them to powerful or they will supersede the long guns in the game.

[fredmiracle]

A simpler way to state this would be: Carronades damage counters are add after all other modifiers.

The raking bonus and "first shot" bonus don't compound IIRC, so there would be a precedent for not compounding carronades too...

[The Royal Hajj]

The raking bonus and "first shot" bonus don't compound IIRC, so there would be a precedent for not compounding carronades too...

it appears they do stack...

When playing with Standard Rules, calculate the effect of the Raking rule and the First Broadside rule independently.

One would figure up the additional counters for the Ranking, add them to the normal shots and do the same for the First Broadside. You would not however, add the Raking shot to the normal ones, than take that total and apply the First Broadside rule to it.

[fredmiracle]

it appears they do stack...

One would figure up the additional counters for the Ranking, add them to the normal shots and do the same for the First Broadside. You would not however, add the Raking shot to the normal ones, than take that total and apply the First Broadside rule to it.

Yeah, additive but not compounding.

So if you have a gunnery factor of 5, and were firing a a hypothetical 1/3 bonus carronade rule, a first broadside, and a stern rake you would draw 5 + (5/3 = 2) + (5/3 = 2) + (5/2 = 3) = 12 chits, not ((5 + (5/3 = 2) = 7) + (7/3 = 3) = 10) + (10/2 = 5) = 15

[The Royal Hajj]

As a trade off...

At long range (A) you subtract the current fore/aft guns from your full broadside for having carronades.
At medium range (B down to the C/D range) it as printed on the ship log.
At close range (C/D) you add the fore/aft guns as bonus A damage counters.

That works alright for full broadsides, but not at all for shooting with the fore or aft guns :(

[The Royal Hajj]

As a trade off...

At long range (A) you subtract the current fore/aft guns from your full broadside for having carronades.
At medium range (B down to the C/D range) it as printed on the ship log.
At close range (C/D) you add the fore/aft guns as bonus A damage counters.

That works alright for full broadsides, but not at all for shooting with the fore or aft guns :(

And if I can quote and reply to my self....

If the notion of less math is thrown out the window, we could use that same long, medium, short principle to the standard 1/3 rule already in the game...

A Range: subtract 1/3 (rounded up) current guns from firing arc
B Range: Normal shots
C/D Range: add 1/3 (rounded up) current guns from firing arc

[Andy Blozinski]

As a trade off...

At long range (A) you subtract the current fore/aft guns from your full broadside for having carronades.
At medium range (B down to the C/D range) it as printed on the ship log.
At close range (C/D) you add the fore/aft guns as bonus A damage counters.

That works alright for full broadsides, but not at all for shooting with the fore or aft guns :(

I kinda like this really simple version.

[Пилот]

Seems fair!

[DeRuyter]

Shouldn't this thread be in the "House Rules" forum? Just sayn'

[David Manley]

Yes of course it should

[The Royal Hajj]

Its in there right?

[DeRuyter]

Now it is. Thanks David! What about the other thread started in "The Chippy Shop" forum - the Howitzer thread?

Just trying to be ship shape and Bristol fashion!

[David Manley]

Just trying to be ship shape and Bristol fashion!

Best way to be

[Diamondback]

Actually, I just saw an intriguing theory about Andrea's numbers, which gave me an idea...

Per another poster, the gun numbers are broadside weight in pounds, rounded to nearest 100 and divided by 100. What I'd propose, IF this is correct, is we add up the gun and carronade weights and figure out their draw values separately, then add the CRDE broadside to the guns at S and subtract at L.

By this logic, looking at HMS Victory as an example...
1765 as-built would see a broadside of 1032# from guns, 0 from carronades. Short, Medium, Long standard effect. Full broadside 10 S, 10 M, 10 L.
1779 rearm is 1032# guns, 48# carronades. Carronade weight insignificant, stats unchanged.
1781 rearm is 1032# guns, 80# carronades. Enough CRDE weight for 1 broadside unit. Full broadside 11 S, 10 M, 9 L.
1783 rearm is 1068# guns, 110# carronades. Full broadside 12 S, 11 M, 10 L.
1793 rearm is 1068# guns, 32# carronades. Disregard carronades, full broadside is 11 S, 11 M, 11 L.
1803 rearm is 1080# guns, 32# carronades. Gun gain over 1793 insignificant, still 11 S, 11 M, 11 L.
1805 Trafalgar fit is 1080# guns, 68# carronades. Gain of 1 CRDE draw over 1803. Broadside 12 S, 11 M, 10 L.

Simple and straightforward enough? Also might be good for creating Custom Card logs to give ships a little more variety and "uniqueness" if it works.

[David Manley]

then add the CRDE broadside to the guns at S and subtract at L.

Why subtract at L? If I had a ship that scored a broadside of 8, and then the ship was refitted and given additional carronades that boosted this to a 9 at S why would I reduce its long range firepower if the long range guns were unchanged?

[Diamondback]

Fair question--my first thought was to give it as a bonus with full value at Short and half-value rounded up at Medium leaving base guns only at Long, but then I wanted to try for something simpler like what Da Boss had suggested while still tacking toward better fit for historical proportions.

Done this way, the stats above would change to...
1765 as-built full broadside 10 S, 10 M, 10 L.
1779 rearm stats unchanged from '65.
1781 rearm full broadside 11 S, 11 M, 10 L.
1783 rearm full broadside 12 S, 12 M, 11 L.
1793 rearm full broadside is 11 S, 11 M, 11 L.
1803 rearm still 11 S, 11 M, 11 L.
1805 Trafalgar fit broadside 12 S, 12 M, 11 L.

[DeRuyter]

Fair question--my first thought was to give it as a bonus with full value at Short and half-value rounded up at Medium leaving base guns only at Long, but then I wanted to try for something simpler like what Da Boss had suggested while still tacking toward better fit for historical proportions.

Done this way, the stats above would change to...
1765 as-built full broadside 10 S, 10 M, 10 L.
1779 rearm stats unchanged from '65.
1781 rearm full broadside 11 S, 11 M, 10 L.
1783 rearm full broadside 12 S, 12 M, 11 L.
1793 rearm full broadside is 11 S, 11 M, 11 L.
1803 rearm still 11 S, 11 M, 11 L.
1805 Trafalgar fit broadside 12 S, 12 M, 11 L.

So in the game Short range is C/D, medium is 1/2 ruler and long is full ruler?

[Berthier]

Fair question--my first thought was to give it as a bonus with full value at Short and half-value rounded up at Medium leaving base guns only at Long, but then I wanted to try for something simpler like what Da Boss had suggested while still tacking toward better fit for historical proportions.

Done this way, the stats above would change to...
1765 as-built full broadside 10 S, 10 M, 10 L.
1779 rearm stats unchanged from '65.
1781 rearm full broadside 11 S, 11 M, 10 L.
1783 rearm full broadside 12 S, 12 M, 11 L.
1793 rearm full broadside is 11 S, 11 M, 11 L.
1803 rearm still 11 S, 11 M, 11 L.
1805 Trafalgar fit broadside 12 S, 12 M, 11 L.

Very simple, elegant and more importantly understandable. Like it.

[The Mad Hatter]

So looking at one of the heavier frigates out there who carried a significant number of carronades, took a look at an Endymion class 40-gun fifth rates (as designed).

As designed it was equipped with - 28x24pdrs on her upper deck, 16x32pdr carr on her quarterdeck, 2x9pdrs and 4x32pdr carr on her forecastle.

So that would mean she throws 410# of cannon shot, and 640# of carronades. So would that equate to something like 7S / 7M /4L?

If I'm understanding your formula correctly, I'd end up with something in that neighborhood I believe. I just took 400/100 for long, 600/100 and split it between short and medium (adding to what the cannons gave it)? I couldn't figure out the rationale above for when you bumped only short or short and medium, so I just split the adding of carronade weight between the two range bands - 3S and 3M added to the 4 from the cannons.