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Neil, do you have a copy of John Harlands 'Seamanship in the Age of Sail'?
Thanks! I've been working on it on and off since about 2011.
The weather is from climate modelling data from here - https://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis2.html - for 1980. Another source I looked at was here, from weather forecasting - https://nomads.ncep.noaa.gov
I just spent half an hour watching videos of Nassau 1715. I wasn't aware of it at all - it looks fantastic.
Yes it's a classic sailing model dilemma where one improvement causes problems in another area. Getting underway is already reaaalllllly slow from a gameplay perspective (I really have no idea what's realistic here). More importantly it would make tacking a lot harder if you increased low speed drag.
How long should a ship take to slow down? Well in a small boat, you coast to a stop very rapidly, whether power or sail. The ship stops rapidly when tacking, due to wind pressure on the sails. My gut tells me that stopping due to water drag along should not be more than 2-3 times slower.
All in all, it's the kind of situation that would make me want to create some sort of artificial braking effect when the sail area is under a certain threshold.
Didn't they usually bring the ship to a stop by backing sail(s) and/or turning into the wind and then dropping anchor?
>All in all, it's the kind of situation that would make me want to create some sort of artificial braking effect when the sail area is under a certain threshold
I would think it's possible to condition the drag not only by sail area, but also by checking if the ship accelerates or decelerates.
P.S. Here are two articles concerning period ship maneuverability I found recently - maybe they can be of help.
The usual procedure was to bring the ship into the wind, then drop the anchor while making sternway. Unless there was a very tricky confined harbor, they wouldn't drop the anchor while still moving forward. I haven't actually tried backing sail that much yet. Even if that method works well, I would still say that the issue is the large disparity in deceleration time of luffing up under full sail vs drifting under bare poles.
Those are fantastic articles and definitely read them. I think your simulation already jives nicely with the information they contain.
>I think your simulation already jives nicely with the information they contain.
I am afraid you have confused me with Neil. :) The game I work with allows much less, although I tried to mix the numbers available to implement at least some of the effects.
There is some experimental data from the Black Sea Fleet reports of the Russian Navy made in 1828-1829:
for several ship types ( from 110-gun first rate to small brigs). Unfortunately it does not contain acceleration or deceleration times, but there are speeds and heel angles for various wind conditions as well as times recorded for tacking and wearing.
For example a 44-gun frigate (table 1, col. 4, and it should be noted Russian ships were in general more heavily armed and slower then their French or British counterparts, even if they shared a hull form):
Wind rate 5
- Close-hauled 7 kt
- Beam reach 9.5 kt
- Broad reach 11 kt
- Running 8 kt
Wind rate 7
- Close-hauled 4 kt
- Beam reach 9.5 kt
- Wind rate 5 - 11 deg
- Wind rate 7 - 7 deg
- Wind rate 9 - 8 deg
Wearing (wind 5): 2.5 min
Tacking (wind 5): 2 min
Tacking (wind 7): 3 min
P.S. Found in the text a description of sails set during the trials:
- At wind 5 (up to 10 m/s) running & broad reach all sails (sic) were set.
- At wind 5 beam reach & close-hauled royals & skysails taken in.
- At wind 7 (up to 15 m/s) courses, topsails (double-reefed), t'gallants and fore-staysails were set.
- At wind 9 (up to 20 m/s) fore-course and fore-staysails were set.
P.P.S. Corrected the wind 5 close-hauled config translation and wind 7 close-hauled speed.
Thanks! That's really good stuff.
There must be similar British reports somewhere, but the only references in the "Frigates of the Napoleonic Wars" list only top speeds and general impressions of the captains.
What page says they set the topgallants in Beaufort 7? (I speak Russian)
Look at page 4 on the left.
При ветре 7 баллов (до 15 м / с) корабли с прямым вооружением несли нижние паруса, брамсели, фор-стень-стаксель; брали два рифа у марселей.
Yikes. I wouldn't recommend flying topgallants in 36 kts of wind in the simulator.
Maybe it wasn't that bad over double-reefed topsail. That makes the t'gallant significantly lower, doesn't it?
Yes but the mast is still spindly, and it's a gale. 35 kts of wind is TWICE as much pressure as 25! I can only imagine they were saying 'look what I can do!' for the sake of the experiment.
I know you refer to the Lively as the basis, but the broadly similar Leda class has a bit more information available... and she is a 1091 tun BM ship, displacing only around 1496 ton.
2000 is closer to the displacement of the much larger US superfrigates such as President/Constitution - 1576BM, 2200 tons.
Thanks for noticing this. I looked in the editor, and the mass of the ship is 1923 tons. 1800 tons of this is the hull (the guns are 90). It looks like this 1800 figure is one I wrote in by hand, rather than calculated, and I don't remember where I got it from.
I can see the relation displacement = about 1.5*burthen in a few places. I have one source, "The Command of the Ocean" by N A M Rodger, on the 18th century royal navy, that says "for a fully stored warship" the displacement is about twice the burthen. Do you know what the state of storage is for your figures?
This is something I am reluctant to mess with, as I am happy with the way the acceleration, stability etc. are tuned at the moment. But I will have to look at this stuff again if I ever get around to flooding and sinking.
I looked at the shot damage code (possibly for the first time since 2014). I'm tracking the kinetic energy of a shot. According to a comment in the code, an 18 pounder shot at 500m/s penetrates 2ft of oak, and I call it a hulling if the energy is more than that (with some randomness). For damage to crew and rigging etc. I just came up with some numbers that seemed reasonable, which shouldn't be hard to tune.
I set the rate of fire at the maximum plausible one. I agree it's a touch high. It would be good to model this better, and change it over time with crew strength and morale etc. Some of the code for this is there already but I'm afraid I'm unlikely to get around to fixing this up.
(And sorry, it looks like the 9 lbers are actually firing 18lber shot.)
Thanks for the questions. Sorry for not replying to this before - I only just saw it.
I am away from my PC right now. The way it should work at the moment is that the sideways lift generated by the rudder does not care whether you are going forwards or backwards (it probably should care). The place that the lift acts is interpolated between a particular position forward, at 1m/s, to a particular point aft, at -1m/s. I don't remember how I set up the aft point. The forward point is somewhere around 1/3 of the way from the front of the ship. It's tuned fairly carefully; I want enough instability so that you have to worry about the sail plan, but not so much that tacking becomes trivial. You can move this point around in one of the debug menus, there's a slider called "ardency" or "griping" or "by the head" or something like that.
Why do you think there is too much authority with sternway?