acceleration Fat bottomed girls and Napoleonic box ships

[jodgi]

“Make a quick write-up”, I thought. Yeah, well… TL;DR at the bottom.

We’ll get to play with new-old acceleration soon that some of you whippersnappers might not have tried. The idea is to (hopefully) drastically reduce acceleration globally.

I hope we also get acceleration based on hull size and shape. There have been differences in acceleration all along, but now with speed-Bellonas, Aggies and Rättvisans having much more firepower than the superfrigates, the game could use some help with viability between those “classes” in particular: The old school fat-bodies and the Napoleonic box ships.

Here’s a reference of how much acceleration has increased since it was originally balanced.

To my knowledge the increase hasn’t been deliberate and intentional but rather a by-product of various other changes and increased fidelity of the sailing simulation. We now have Endys that that can broad reach from 0 to 10 knots in 10 seconds or Connies that can do the same at beam reach in 22 seconds where it took about 80 seconds before. Even with the partly accelerated instance dynamic, it is clearly way, WAY too much to represent these ships in the best possible manner.

“What’s it to me, jodgi?”

Two things mainly. You may experience a loss of comfort when your ship accelerates slower than what you’ve grown used to. Feel free to use your cognitive abilities to keep the inevitable emotions in check when it hits you.

Slower acceleration will also tax your planning and ship handling abilities. I suppose some of you have experience with driving large vehicles and can attest to the added mindfulness and planning that is required for the safe operation of humongous kinetic energy vehicles.

I’ve had to read up to get learnt about ships, speed and acceleration. I currently know enough to make a complete fool of myself by boldly speaking of things I now should know I know too little about [breathing and contemplation pause].

“Principles of Naval Architecture, Vol II” has a section concerning the resistance a body is subjected to when moving through a fluid. Since you’re all a bunch of monkeys I’ll just point out some highlights. The total resistance is broken up in parts. A ship has to push away water according to its displacement (The old guy in the bathtub, remember?) waves and eddies form and that makes up 15-20% of the resistance. 80-85% of the resistance is friction.

Some old English dude (duh) called Froude did some pretty nifty studies on planks he towed around in water. (Oh, look! another old guy in a bathtub!). Up until then shipbuilders relied on true and tested ideas with some rough rule-of-thumb math like “hull speed” (Vhull = 1.34 ∙ √Waterline length). Froude found that short planks had higher friction per unit area than long planks, he attributed this to water being accelerated along the length of the plank thus lowering relative speed which in turn result in less friction. The takeaway is this: Canoes suffer less friction moving through water than stunted prams. There is, of course, more to this story but if I drone on this particular subject I’m afraid you’ll start eating your crayons.

Let’s look at our ships. Let’s assume the surface areas exposed to water on Constitution and Rättvisan are the same, they prolly aren’t but play along, please. The ship with the highest length/girth ratio would have the lower resistance and thus the highest potential for both top speed and acceleration. Yes, simplified, specifically for you, dear.

Wouldn’t that be neat as a balance parameter?
The simplest way is to make acceleration a function of speed. But we can mix it up with our ships that sometimes have very similar speeds but clearly different length/width ratios. If we use the simplest ratio almost ignoring the area of the wetted surface a Connie could accelerate 12% better than a Bellona, I suspect this would make negligible difference in the game so we could bump it to 25% and balance shit from there.

Froude even towed a whole ship around and measured total resistance. It catches my interest because then we can clearly make out how much force (component vector along the line of travel) the sails would have to produce to propel the ship to a given speed. Just look! That's eight and a half metric tonnes of wind thrust to maintain almost 12 knots for the Greyhound! You can see that the increase in resistance with speed pretty much matches our in-game acceleration curves. Neato.

I wonder if our deceleration curves also reflect this? I should do a test…

Buckle up, Busters! NA is about to get more real!

TL;DR
Hell, no! If you can’t read it all and frikkin’ enjoy yourself in the process you have no business playing this game!
 

[Eyesore]

You're in danger of becoming a crafter?  😉

Edited April 9, 2019 by Eyesore
your = you're :-p

[Teutonic]

Makes sense.

Although it is possible the speed nerf may address some issues - i honestly wasn't aware of ship acceleration changing through the years/patches though. Interesting to see data of it.

[jodgi]

2 minutes ago, Teutonic said:

i honestly wasn't aware of ship acceleration changing through the years/patches though

You're not alone, let me tell ya.

[Socialism]

I was told there was a TLDR...

[Hethwill]

Thanks for bringing this up Jodgi.

[Fluffy Fishy]

This doesn't really work with Constitution as an example, Constitution has far more mass under the water than Agamemnon and Rattvisan, Constitution is slightly thinner but has a much deeper draught. The illusion of Constitution being a much faster ship purely because she is a "frigate" doesn't really make sense. Constitution does have a better sailing ratio but this is only really due to her incredible length as a ship, Comparing hulls, Rattvisan and Agamemnon aren't too dissimilar shapes and aren't really blocky, if anything Constitution is a more square shape than the two ships you are comparing her to who both have some really quite nice hydraulic lines.

Measurements:

• Length
  • Constitution: 63m
  • Agamemnon: 48.77m
  • Rattvisan: 49.6m
• Width
  • Constitution: 13.26m
  • Agamemnon: 13.44m
  • Rattvisan: 13.59m
• Draught:
  • Constitution: 7m
  • Agamemnon: 5.19
  • Rattvisan: 5.79m
• Tonnage (BM)
  • Constitution: 1576
  • Agamemnon: 1,383.6
  • Rattvisan: (Around 1400-1425?)

Plans:

 

Constitution

Agamemnon

Rattvisan

Edited April 9, 2019 by Fluffy Fishy

[Malachi]

2 hours ago, jodgi said:

The ship with the highest length/girth ratio would have the lower resistance and thus the highest potential for both top speed and acceleration.

This is true but we´re talking sailing ships. Out of two vessels with the same wetted surface area, same draft, but a different length/breadth ratio, the one with more beam is most probably more stable and thus able to carry more sail in the same wind conditions. And there´s a good chance that this more than offsets the theoretical high L/B ratio speed advantage.

One of the fastest frigates in the Age of Sail had a length/breadth ratio of around 3.50 and her body plan looks like a box with slightly beveled edges. Didn´t matter, because she simply 'outcarried' her competition.

Edited April 9, 2019 by Malachi

[jodgi]

3 minutes ago, Malachi said:

This is true but we´re talking sailing ships. Out of two vessels with the same wetted surface area, same draft, but a different length/breadth ratio, the one with more beam is most probably more stable and thus able to carry more sail in the same wind conditions. And there´s a good chance that this more than offsets the theoretical high L/B ratio speed advantage.

One of the fastest frigates in the Age of Sail had a length/breadth ratio of around 3.50 and her body plan looks like a box with slightly beveled edges. Didn´t matter, because she simply 'outcarried' her competition.

Ye, fat ladies being strong enough to pack on enough sail to simply brute force their way past the pretty competition... You could've laid on with open ocean waves and the nose push and whatever other factors they had to deal with at the time.

I bet there aren't a whole lot of recorded data on acceleration alone? In any case, it doesn't matter.

What would you suggest about acceleration and game balance? Bellona and connie are currently placed in the same class. They have clearly different L/B ratios sailing in one single sea state and one single wind state and are both able to set all sails at any point of the wind. Should connie be allowed to accelerate faster than Bellona or not? What would our gameplay and ship viability choices be? This isn't all about connie (I have no hope in the permit grind, anyway), can we differentiate between ships and spice up gameplay without completely violating historical records?

What is this ship you speak of, btw, it doesn't sound like the Endy (based on gun deck length)?

[jodgi]

Thanks for the numbers and interesting input, @Fluffy Fishy

I do notice that of those ships it's the connie that more closely resembles the modern "Deep V" hull form that helps with reducing resistance.

I'll give you the same game balance rooted challenge: What about ship diversity and spice in gameplay? How to do without making a mockery of it?

[Malachi]

26 minutes ago, jodgi said:

What would you suggest about acceleration and game balance? Bellona and connie are currently placed in the same class. They have clearly different L/B ratios sailing in one single sea state and one single wind state and are both able to set all sails at any point of the wind. Should connie be allowed to accelerate faster than Bellona or not? What would our gameplay and ship viability choices be?

Quite honestly, I have no idea. You could play around with wetted surface / sail area ratios (the former easily obtained from the ingame models) but such numbers would just give a hint at the potential performance, no 'hard evidence'. Regarding Connie/Bellona: I'd hazard a guess that Connie has a larger sail area, so she theoretically should accelerate faster. If that would be beneficial for gameplay is another jolly good question.

 

26 minutes ago, jodgi said:

What is this ship you speak of, btw, it doesn't sound like the Endy (based on gun deck length)? 

Slade's Niger/Alarm class.

125' / 35' 2'' , L/B 3.55

11 knots close-hauled and 13,5 knots with the wind abaft the beam. Extremely responsive, liked heavy weather and could carry her sails 'as long as her masts would bear it'.

Edited April 9, 2019 by Malachi

[van der Clam]

Does mast spacing have anything to do with catching wind and being able to accelerate a ship faster? I'd assume there are historical materials on this. In my little brain, I would think a 3 masted ship with masts 3 feet apart (exaggeration) would not catch as much wind as a 3 masted ship with masts being farther apart. It's the idea of stealing wind...but instead, masts being too close would steal wind from ourselves. So in my mind a longer ship would provide a greater distance between masts, providing better wind capture; hence why the Connie would have better acceleration than the fat bottomed girls. However, I have no idea the dimensions of any of these ships and their mast spacings to make anything better than my simple-minded guess.

BTW, this reminds me of a forum discussion sometime last summer (or maybe longer ago) about "stealing wind" from the enemy being implemented in this game. Did that happen and I not notice? or is it not a thing in game? 

[Sir David Green]

Stealing wind would be interesting, and realistic. HMS Revenge when it tried to make her run through a Spanish fleet was stopped in her tracks because of a huge Spanish ship blocking the wind with her sails.

[Rex Maris]

The boat that weighs less acellerates faster. And the ship with the most lenght  always has a faster top speed except in the condición os glide. But in the game we always have  the same intensity of  wind so It is very dificult to capture the actual speed if the boats.