Hello everyone,
I want to share an idea I had about the sailing mechanics in Sea Of Thieves being a little more difficult and realistic. Basically, the acceleration of the ship should be determined by the angle of the wind and the speed of the wind relative to the ship's own speed (apparent wind).
So I built a little excel sheet that would calculate the steady state of the differential equation for sailing, where forces are applied realistically.
There are a couple of different forces in my model:
Motor force: This force is not a realistic force, it just pushes the ship forward to help with sailing upwind and makes everything a little more forgiving.
Sail force: Sail force is calculated by taking the cosine of the angle between apparent wind and sail multiplied by the cosine of the angle between sail and ship multiplied by the apparent windspeed squared multiplied by the area of the sail. This essentially means you have to put your sail between the direction of travel and the direction of wind to achieve the most acceleration. I.E. if the wind is coming directly from the right, you have to put your sail at about 45° instead of 90°. Note that sail force CAN slow the ship down if the sails are angled against the wind the wrong way
Drag force: Without drag ships would accelerate forever. Drag is calculated by multiplying some drag constant with the squared ship speed.
Different ship types can have different sets of variables for sail area, motor force and mass to make them handle differently. For instance, the sloop has a lot more motor force, smaller sails and less mass, meaning it can deal better with head wind, accelerates faster, but doesn't have such a high top speed.
Diagramms: The way you would read them is as follows:
Green is the sloop, blue is the brigantine and red is the galleon. The orange arrow indicates the direction of the wind. Draw a line from the origin of the diagram in the angle you want to put your sails. So if you keep your sails pointing straight forward, you draw a line straight up, if you angle your sails 45° to the right, draw a line accordingly. Now mark the point where your line crosses the max-speed-curve of your ship type. The distance between the origin and the cross is the top speed you will achieve.
This is pretty self explanatory for the 0° wind example, as the galleon will achieve a top speed of 3m/s, keeping its sails at 0° and a top speed of about 1m/s, if it put its sails all the way to the right or left.
Now that we understand how my model works, let's look at some other wind directions.
As you can see here, you will actually achieve the best top speed with the sails slightly further to the side than 45°, in fact it's more like 50° to 55°, this is called apparent wind compensation. You will also note that you can sail faster in crosswind than you can with tailwind, which is also true to nature and surely an interesting game mechanic. One other thing to note is that the sloop could still sail even if it had it's sail all the way to the left, which the galleon could not. This basically means that crews on bigger ships have to pay greater attention to their sails, because (im)proper sail angles will be rewarded/punished more heavily than on smaller ship types. (balancing and all)
This is also true for side wind. A sloop with its sails straight forward could still reach 1m/s, while a galleon doing the same thing will barely make 0.6m/s
This is the first example of partial head wind. Note that smaller ship types are generally more capable during these conditions, making it easier to escape big ships.
sailing directly into the wind is possible due to the aforementioned motor force, but you will significantly increase your speed by angling your sails all the way to the side. Again the smaller ships come out with an advantage here.
Here is another set of plots with the sail angle on the x-axis and the top speed on the y-axis, these might be easier to read and understand my point.
I also made a gif, becaue apparently I have nothing better to do.
I apologize for any misspellings or grammar misuses, I'm German.
