Sailing rules suggestions

[KWorld]

Sailing  Rules
[A couple quick ideas, since people seem interested in an 1870 or so start period.  Please comment, these are just thoughts I've had in the last couple hours as I got ready to go to work.]

Sailing rigs
A sailing rig to propel a ship, in normal conditions, at a cruising speed of 7 knots,  will weigh 5% of the ships NORMAL displacement.  Each additional knot of possible speed, up to the hull's natural speed, will weigh 1% of the ships normal displacement.  In the proper conditions, a normal ship-rigged vessel can exceed it's cruising speed by up to 5 knots, by setting extra sails and sailing across the wind.

Sailing
Generally, a sailing voyage has to consider the wind.  If travelling east or west around the globe, the savvy captain will make use of the trade winds to push him on his way.  If travelling north or south, the captain will be cutting across the trade winds in the higher latitudes, but must be aware of the lack of trade winds in the equatorial regions and adjust his route accordingly to make use of more coastal winds (with the related risks of shoal waters and hostile shores).   Sailing ships generally cannot move upwind, they can only move  across the wind or downwind.

Steam and sail operation
It is quite possible to operate under both steam and sail power at the same time, should the wind be running in the proper direction and the captain desiring more speed.

[KWorld]

USS Iowa, USA armored steam frigate laid down 1870)

Displacement:
   3,260 t light; 3,423 t standard; 3,642 t normal; 3,817 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (335.00 ft / 335.00 ft) x 44.50 ft x (15.00 / 15.59 ft)
   (102.11 m / 102.11 m) x 13.56 m  x (4.57 / 4.75 m)

Armament:
      2 - 10.00" / 254 mm 15.0 cal guns - 300.01lbs / 136.08kg shells, 120 per gun
     Muzzle loading guns in deck mounts, 1870 Model
     2 x Single mounts on centreline ends, evenly spread
      10 - 7.50" / 191 mm 10.0 cal guns - 90.00lbs / 40.82kg shells, 100 per gun
     Muzzle loading guns in broadside mounts, 1870 Model
     10 x Single mounts on sides, evenly spread
      24 - 0.45" / 11.4 mm 45.0 cal guns - 0.04lbs / 0.02kg shells, 400 per gun
     Breech loading guns in deck mounts, 1870 Model
     4 x Single mounts on side ends, evenly spread
      4 raised mounts
      Weight of broadside 1,501 lbs / 681 kg

Armour:
   - Belts:      Width (max)   Length (avg)      Height (avg)
   Main:   4.50" / 114 mm   217.75 ft / 66.37 m   8.00 ft / 2.44 m
   Ends:   Unarmoured
     Main Belt covers 100 % of normal length

   - Protected deck - single deck:
   For and Aft decks: 1.00" / 25 mm

Machinery:
   Coal fired boilers, simple reciprocating steam engines,
   Direct drive, 1 shaft, 3,722 ihp / 2,777 Kw = 15.00 kts
   Range 2,500nm at 7.00 kts
   Bunker at max displacement = 394 tons (100% coal)

Complement:
   233 - 304

Cost:
   £0.270 million / $1.079 million

Distribution of weights at normal displacement:
   Armament: 78 tons, 2.2 %
      - Guns: 78 tons, 2.2 %
   Armour: 490 tons, 13.4 %
      - Belts: 333 tons, 9.1 %
      - Armour Deck: 157 tons, 4.3 %
   Machinery: 912 tons, 25.1 %
   Hull, fittings & equipment: 1,379 tons, 37.9 %
   Fuel, ammunition & stores: 382 tons, 10.5 %
   Miscellaneous weights: 400 tons, 11.0 %
      - Above deck: 400 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     2,880 lbs / 1,306 Kg = 8.2 x 10.0 " / 254 mm shells or 1.0 torpedoes
   Stability (Unstable if below 1.00): 1.26
   Metacentric height 2.3 ft / 0.7 m
   Roll period: 12.4 seconds
   Steadiness   - As gun platform (Average = 50 %): 75 %
         - Recoil effect (Restricted arc if above 1.00): 0.34
   Seaboat quality  (Average = 1.00): 1.51

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.570 / 0.575
   Length to Beam Ratio: 7.53 : 1
   'Natural speed' for length: 18.30 kts
   Power going to wave formation at top speed: 36 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 0.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00 %,  13.00 ft / 3.96 m,  11.00 ft / 3.35 m
      - Forward deck:   30.00 %,  11.00 ft / 3.35 m,  10.00 ft / 3.05 m
      - Aft deck:   35.00 %,  10.00 ft / 3.05 m,  10.00 ft / 3.05 m
      - Quarter deck:   15.00 %,  10.00 ft / 3.05 m,  10.00 ft / 3.05 m
      - Average freeboard:      10.51 ft / 3.20 m
   Ship tends to be wet forward

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 90.9 %
      - Above water (accommodation/working, high = better): 86.3 %
   Waterplane Area: 10,317 Square feet or 958 Square metres
   Displacement factor (Displacement / loading): 122 %
   Structure weight / hull surface area: 93 lbs/sq ft or 453 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.97
      - Longitudinal: 1.35
      - Overall: 1.00
   Adequate machinery, storage, compartmentation space
   Cramped accommodation and workspace room
   Ship has slow, easy roll, a good, steady gun platform
   Excellent seaboat, comfortable, can fire her guns in the heaviest weather

10" guns are rifled pivot guns mounted fore and aft, while the 7.5" guns are smoothbore weapons on the broadside.  .45" guns are 6-barrelled Gatlings on pivot mounts atop the deckhouse amidships.

Above-decks miscellaneous weight is masts and sails sufficient to propel the ship at up to 13 knots in normal conditions (11% of normal displacement).  Under combined sail and steam power, 17 knots is achievable under normal conditions.

[Nobody]

For comparison I tried to look up the weight distribution of some sailing ships, without much luck though.

I did found out, that the current "Gorch Fock" training ship carries about 300 tons of ballast in her kneel. Mind you, she is only a 1640 ts (max) ship about 80 meters long with a top speed of around 16 knots (under sail).



I just had a (completely) different idea for the sails:
- choose top speed as ususal
- add misc wight for every horsepower the ships supposed to have under sail

[KWorld]

For comparison I tried to look up the weight distribution of some sailing ships, without much luck though.

I did found out, that the current "Gorch Fock" training ship carries about 300 tons of ballast in her kneel. Mind you, she is only a 1640 ts (max) ship about 80 meters long with a top speed of around 16 knots (under sail).



I just had a (completely) different idea for the sails:
- choose top speed as ususal
- add misc wight for every horsepower the ships supposed to have under sail

Heh, I haven't seen much of anything that covers how much weight there was in masts, sails, and all the stays and guy lines needed to hold them in place either.

The percentage system I created is essentially doing the same thing as adding misc weight for every horsepower under sail from the reverse side.  To use the example ship, to cruise at under sail 13 knots she needs 2241 hp.  If I used 5 hp per ton as how much sail horsepower per ton were available, that means the ship would need 448 tons to sail at up to 13 knots under sail at cruise.

[Darman]

So... for simming purposes can we assume that this is the basis for a new rule on sails?  Just because I want to start simming a few warships. 

[Walter]

I have been using this rule for my sims already. No one objected to it so we should use it then. :)

[Logi]

I haven't looked into any historical detail, but I've been using it as well. I would suppose there are no objections at the moment from anyone.

[KWorld]

From the looking I did before I created these, the speed seems right.  What could very well be off is the weight, but I haven't been able to find much that gives the weight of period masts, sails, rigging, and crew to operate those.  :(  So I came up with an estimate.

[Nobody]

I'm have no idea if the weights and speeds are adequate.

There is one thing I would criticizes though:
There is no advantage for a longer ship in there (except a higher possible top speed at ridiculous cost maybe).

So maybe use a ships half (or third) natural speed instead of the fixed 7 knots for 5% displacement? And leave the rest (+1 kn per % spent extra).

[Darman]

So maybe use a ships half (or third) natural speed instead of the fixed 7 knots for 5% displacement? And leave the rest (+1 kn per % spent extra).

I kind of like this idea, because then it gives people who design their ships for a faster natural speed a bonus, rather than having to spend more weight to make up the difference in speed.  I could have a ship with a natural speed of 7 knots and only pay 5% of my normal weight versus someone who did a much better job and has a natural speed of 10 knots, they have to pay 8% to get the full benefits of their vessel's natural speed. 

I believe that it would be great if we could get the perfect historical numbers, but that is highly unlikely and so what we need instead is a serviceable system that can be applied consistently and is loosely based on historic figures. 

[KWorld]

Historically, the fastest sailing ship built until a multi-hull took the title in 19844, the clipper ship Sovereign of the Seas hit 22 knots in 1854.  She had a length of 525 feet, which in SS would giver her a natural speed of 15.87 knots.  I don't think it's a good idea to cut that natural speed in half just because she's a sailing ship.

[Darman]

Historically, the fastest sailing ship built until a multi-hull took the title in 19844, the clipper ship Sovereign of the Seas hit 22 knots in 1854.  She had a length of 525 feet, which in SS would giver her a natural speed of 15.87 knots.  I don't think it's a good idea to cut that natural speed in half just because she's a sailing ship.

The way I read Nobody's proposal was not to halve the natural speed of a ship outright, it was to pay 5% of its normal displacement for sails and rigging for half the natural speed, rather than a set 7 knots.  So the Sovereign of the Seas, in order to hit 16 knots (I rounded the natural speed up), would need to have 14% of her displacement as misc weight for sails and rigging under the current rules.  Under what I believe is Nobody's suggestion (and which I agree with), the Sovereign would need to have 13% of her misc weight as sails and rigging.  (5% misc weight= half the natural speed, 8 knots + 8% misc weight for the 8 additional knots of speed) 
We could also give another little twist on the equation to be able to emulate the Sovereign's feat whereby for every additional knot of maximum speed past her natural speed you must pay 2% of displacement. 

[KWorld]

Gracious, I totally messed up that post about Sovereign of the Seas, didn't I?  She was 252 feet long, and her record wasn't surpassed until 1984.  Yeesh.....



Keep in mind that Sovereign of the Seas, like the other clippers, was a merchant ship, intended to carry cargo (admittedly at speeds greater than the norm in their day).  A quick attempt at SS'ing her is below, but note the instability.


Sovereign of the Seas, United States Clipper ship laid down 1852

Displacement:
   5,167 t light; 5,273 t standard; 5,273 t normal; 5,273 t full load

Dimensions: Length (overall / waterline) x beam x draught (normal/deep)
   (252.00 ft / 252.00 ft) x 45.60 ft x (29.20 / 29.20 ft)
   (76.81 m / 76.81 m) x 13.90 m  x (8.90 / 8.90 m)

Machinery:
   No fuel, Internal combustion motors,
   No drive to shaft, 0 shafts, 28,512 shp / 21,270 Kw = 22.00 kts
   Range 0nm at 0.00 kts
   Bunker at max displacement = 0 tons
     Caution: Too much power for number of propellor shafts

Complement:
   309 - 402

Cost:
   £0.181 million / $0.723 million

Distribution of weights at normal displacement:
   Armament: 0 tons, 0.0 %
   Machinery: 0 tons, 0.0 %
   Hull, fittings & equipment: 2,097 tons, 39.8 %
   Fuel, ammunition & stores: 105 tons, 2.0 %
   Miscellaneous weights: 3,070 tons, 58.2 %
      - Hull below water: 2,050 tons
      - Above deck: 1,020 tons

Overall survivability and seakeeping ability:
   Survivability (Non-critical penetrating hits needed to sink ship):
     3,306 lbs / 1,500 Kg = 71.2 x 6 " / 152 mm shells or 1.5 torpedoes
   Stability (Unstable if below 1.00): 0.92
   Metacentric height 1.3 ft / 0.4 m
   Roll period: 16.8 seconds
   Steadiness   - As gun platform (Average = 50 %): 54 %
         - Recoil effect (Restricted arc if above 1.00): 0.00
   Seaboat quality  (Average = 1.00): 1.08

Hull form characteristics:
   Hull has a flush deck,
     a normal bow and a cruiser stern
   Block coefficient (normal/deep): 0.550 / 0.550
   Length to Beam Ratio: 5.53 : 1
   'Natural speed' for length: 15.87 kts
   Power going to wave formation at top speed: 69 %
   Trim (Max stability = 0, Max steadiness = 100): 50
   Bow angle (Positive = bow angles forward): 0.00 degrees
   Stern overhang: 0.00 ft / 0.00 m
   Freeboard (% = length of deck as a percentage of waterline length):
            Fore end,    Aft end
      - Forecastle:   20.00 %,  22.00 ft / 6.71 m,  19.00 ft / 5.79 m
      - Forward deck:   30.00 %,  19.00 ft / 5.79 m,  17.00 ft / 5.18 m
      - Aft deck:   35.00 %,  17.00 ft / 5.18 m,  17.00 ft / 5.18 m
      - Quarter deck:   15.00 %,  17.00 ft / 5.18 m,  17.00 ft / 5.18 m
      - Average freeboard:      17.94 ft / 5.47 m

Ship space, strength and comments:
   Space   - Hull below water (magazines/engines, low = better): 43.5 %
      - Above water (accommodation/working, high = better): 83.7 %
   Waterplane Area: 7,778 Square feet or 723 Square metres
   Displacement factor (Displacement / loading): 172 %
   Structure weight / hull surface area: 126 lbs/sq ft or 615 Kg/sq metre
   Hull strength (Relative):
      - Cross-sectional: 0.81
      - Longitudinal: 7.03
      - Overall: 1.00
   Caution: Poor stability - excessive risk of capsizing
   Excellent machinery, storage, compartmentation space
   Cramped accommodation and workspace room

Warning: Too much power for number of propellor shafts

[Walter]

I made a pure sailing ship with SS using our 7 knots =5% rule. I actually simmed it entering 1 at the speed, shaft, range and cruising speed, so I do not need to worry about any warnings it may give.

[KWorld]

I entered the higher speed to get decent seakeeping at speed.  The warning about propellors I didn't worry about, since the ship doesn't have props.