Looking around, I have found a need for a comprehensive guide on the most efficient use of speed sails, cargo racks, and long-distance resource hauling. Especially now that singleplayer mode allows for quick and easy testing, we need to get more factual information about ATLAS out to the public. For simplicity's sake, I will avoid discussing weight sails, handling sails, and item quality (maybe you can look forward to a guide on those subjects from me in the future).
Answering individual questions
Quick summary of results
Explanation of singleplayer testing
As a TL;DR, here are the questions I will be answering today and a quick summary of the answer:
How do ship speed, sails, and weight work behind-the-scenes?
Every ship has a max speed, if it theoretically weighed 0 lbs. Each sail you add contributes to the max speed, linearly. The speed is related to the square root of the percentage of your ship weight that is not filled. The following table has a few notable percentages (the speed % is compared to the max speed).
For each type of ship, what speed sail configuration (small/medium/large) gives the fastest ship?
sloop: 1 medium and 1 small speed sail
schooner: 1 large and one small speed sail
brig: 3 large speed sails
galleon: 6 large speed sails
What ship is the fastest?
Contrary to popular belief, with optimal sails, galleons are the fastest, followed closely by schooners, and then brigantines and finally sloops (rafts aren't real ships :P).
How many cargo racks should I put on my ship to get the fastest ship?
This is a very complex question that depends on your ship type, the total weight you want to carry, your max weight, and the "empty" weight of your ship. As a rule of thumb, add a cargo rack if you have another 4,000 lbs in resources to put in one, and make sure you fill existing cargo racks as much as possible before adding more.
What is the optimal way to haul resources long distances in as little time as possible?
Once again, this depends largely on the factors in the previous answer. As a rule of thumb, load up your ship to around 50% weight when you are hauling resources.
Here are some related questions that I Won't be answering today, but I will include some links to people that have answered them in the past (to varying degrees of thoroughness and accuracy - be your own judge on the matter):
How accurate is the in-game depiction of knots (speed)?
Do higher-quality (fine/journeyman/etc.) sails actually give any benefit?
For a more in-depth discussion on each of these questions, keep reading! I will lead you through the testing I have done in singleplayer mode, and we will discuss factors that I had to ignore while testing, etc. Onward to information!
IMPORTANT NOTE BEFORE WE BEGIN: I am going to use the terms "maximum speed" and "speed" throughout this guide, and these each refer to a different concept. The maximum speed of a ship is the theoretical maximum speed it could go if it weighed 0 lbs. The speed of a ship is the actual speed of the ship, with whatever weight it currently has on it. Most of the math is done with the maximum speed, not the current speed. I will start by talking about how to use the speed and weight of a ship to compute the maximum speed.
How do speed, sails, and weight calculations work behind-the-scenes?
Ship speed depends on the type of ship you are sailing, the number and type of sails your ship is equipped with, the number of cargo racks on board, and the weight percentage. We will discuss all of these things here. I will lead you through the testing I did and try to explain some of the nuances that I had to think about
First - The effect of weight on ships:
My results: Ship speed is related to the weight of the ship according to the following equation:
speed = speed_max * sqrt(1-weight/max_weight)
NOTE: This does not take into account cargo racks - see the equation below for a more complete equation.
This results in a graph like the following:
The maximum speed depends on the ship you are in and the sails you use - we will discuss this more in a bit. Since the speed changes as the square root of the remaining weight, you can see that the weight drops off really quickly as you get closer to 100% full. Thus, any weight above around 80% starts to really slow the ship down, and for that reason, I suggest never sailing above 85% capacity, since you just travel too slow.
My testing method: I spawned each ship in using ssf <sloop, schooner, brigantine, galleon> (pick one of the arguments in the <>). I set up the wind using the commands setwind 100 and setignorewind true (both are necessary for consistency). Then I opened the sails to full and marked down the current weight of the ship and the speed, once it stabilized. Using this method, the ship speed is very stable, unlike in the actual servers, where the speed bounces all over the place. Now, I used the admin command gfi gem_base 500 0 0 to get 500 gems, and I recorded the weight and speed - rinse and repeat until the ship stops moving. We now have a data for ship speed versus weight. Plotting the speed of the ship versus the square root part of the equation above, I got a straight line with the slope equal to the maximum velocity for that sail arrangement:
NOTE: Keep in mind that this method will spawn a schooner with 2 medium speed sails and a galleon with 5 large speeds sails, both of which are not the optimal sail arrangement. The max speed I got from these tests just correspond to a sub-optimal layout of sails. The important part here is how straight these lines are, which proves that this equation is correct.
This is a great fit, so I am pretty confident about the equation and the max speeds we get from this method. From now on, we can just manipulate the speed equation to solve for speed_max if we know the weight and speed of the ship. This will be useful in the next section.
Second - The effect of sails on the speed of a ship:
My results: Sails add linearly to the max speed of a ship. That means that half as many sails will push the ship half as fast. However, I found it surprising that each type of sail increases the max speed differently for each ship. The following table summarizes my results.
If you can find any patterns in that data, please let me know - I couldn't find anything. The main thing to note with this table is the speed per sail point. Remember that small sails cost 1 sail point, mediums cost 1.7, and larges cost 2.66 (ATLAS rounds this to 2.7, but it actually is 2.66 when you add multiple). The sails get more speed per point the larger you get (looking at a single ship). This means that it is always beneficial to use as large of sails as possible, and fill in any remaining points with smaller sails. This leads to the following optimal configurations:
Sloop: 1 medium speed sail (max speed is 16.03 knots)
Schooner: 1 large and 1 small speed sail (max speed is 21.05 + 4.55 = 25.6 knots)
Brigantine: 3 large speed sails (max speed is 23.79)
Galleon: 6 large speed sails (max speed is 26.88)
NOTE: I discuss the optimal sail configuration more in the next section.
This means that galleons are the fastest ship, followed closely by schooners, and then by brigs and sloops are the slowest. This is important, since many people tend to believe that schooners are the fastest ship, but this data shows that they are actually over a full knot slower on average.
My testing method: I spawned the ships as I did above. This time, I removed all sails and set up the configuration I wanted to look at (for example, 16 small speed sails on a galleon). I marked the weight and speed while slowly removing sails. Plotting the maximum speed (calculated as mentioned above) versus number of sails gave a line, and fitting a linear trendline in excel gave a slope that you see in the table above. If you want to compute the max speed of a ship, just add together the values for each sail from the table above.
Third - How do cargo racks affect speed?
My results: A full set of cargo racks (2 for a schooner, 4 for a brig, and 6 for a galleon) will reduce your maximum speed by 40%. This means that each cargo rack reduces your speed by the following amounts:
Schooner: 20% per cargo rack
Brigantine: 10% per cargo rack
Galleon: 6.67% per cargo rack
If you only have some of the cargo racks, it affects your speed linearly (for example, 2 racks on a galleon reduces your speed by 40% * 2/6 = 13.3%). However, the racks also reduce the weight of anything inside of them by 80%, up to 8,000 lbs pre-reduction. This means that a full cargo rack reduces your ship weight by a total of 6400 lbs (80% of 8,000). The weight reduction will make your ship go faster, but it must counteract the speed reduction just for having the rack on the ship to be beneficial. This is complicated enough that I gave it its own section toward the end of this post. In general, always drop empty racks, and fill up your existing racks before you add another.
My testing method: In singleplayer, spawn in ships as mentioned above. Get the ship up to speed and start adding empty cargo racks. Make sure to take note of the weight each time you add a cargo rack (they weigh 50 lbs each). You can then compute the maximum speed as mentioned above, and the plot of maximum speed versus number of cargo racks gives a straight line. The slope of this line is the maximum speed decrease per cargo rack. This will vary based on your sail configuration, but the percentage speed decrease (speed decrease / maximum speed) will be the same for every ship. Assuming you read the section above about maximum speed, we can update our equation to include the number of cargo racks:
speed = speed_max * (1 - 0.40 * num_racks/max_racks) * sqrt(1-weight/max_weight)
In addition, I added weight to the cargo racks to verify that the rest of the equation still holds with cargo racks. Indeed, you see the same square root behavior. This means that the cargo rack has only the two effects listed above: max speed decrease, and weight decrease.
What speed sail configuration makes the fastest ship/ what type of ship is the fastest?
My results: The table in the previous section summarizes my results about the how each sail type affects the maximum speed of a ship. Using this data, you can see that larger sails are generally more efficient than smaller sails. For example, look at a brigantine: Large speed sail adds 7.93 knots to your max speed, whereas the medium sails add 4.24 to the max speed. This means that the large speed sails add 2.94 knots per sail point, and mediums speed sails only add 2.49 knots per sail point. This is the reason that you should always use larger sails first, then fill in any remaining points with smaller sails.
Using the table on the left, you can see that galleons are the fastest ship in the game, when used with 6 large speed sails. This is followed by a schooner with 1 large and 1 small speed sail, and then by a brig with 3 large speed sails, and finally the sloop with 1 medium speed sail.
My testing method: I mentioned it above, but once again, briefly - spawn in each type of ship and mark down the weight of the ship, the speed you travel, and the number of sails as you vary the number and type of sails on the ship. The plot of maximum speed versus number of sails is a line, and the slope is equal to the max speed increase per sail. As for the optimal sail configuration, I did not test every combination of sails possible for each ship. Although we previously discussed why larger sails are more efficient, this does not automatically mean that using only the largest sails is always going to be the most efficient, since there are some leftover points that could, in theory, be used more effectively. I set up an excel spreadsheet (on the left) with all possible combinations of sails for which you cannot add another sail. Some of these use all of the sail points, and some do not. I then computed the maximum speed with each configuration and looked for the maximum speed out of all combinations. This just so happened to be the result where the largest sails are used first, as mentioned above (and everywhere else). This just proves definitively that there is no odd combination of sails that uses sail points more effectively that beats the tactic above.
How many cargo racks should I add to my ship to maximize speed?
Another way to phrase this question would be - how much cargo would I have to put into a new cargo rack to justify the additional speed decrease? This depends on the ship max carry weight, your ship's "empty" weight, and the number of cargo racks already on your ship. First, let's categorize the weight into "free" and "fixed" weight, by whether or not you can put it into a cargo rack. Fixed weight includes plank weight, repair materials, and crafting stations, to name a few examples. Free weight can include whatever cargo you have on board, armor or tools, or even blueprints (although you shouldn't store blueprints in cargo racks - there are only 100 slots to fill up with 8,000 lbs to be the most efficient).
The reason we want to categorize the weight is because the fixed weight is just dead weight, there is nothing we can do to reduce it. However, it will affect when we should add racks, since the speed is not linear with respect to weight. This means that we should add a rack when the amount of free weight we can store increases the speed of the ship (by reducing the weight) more than the extra cargo rack would decrease the speed. Mathematically, this gives us the equation (where x is the free weight and n is the number of cargo racks currently on the ship)
Obviously, this gets complicated fast, since we want to solve for x... Well, I did that for you, and here is the equation for the amount of free weight you need to store when adding a cargo rack:
where the empty weight is your fixed weight, and f(n) is listed below:
ok, this is still quite complex (we haven't even touched what to do when the free weight is outside of the range between 0 and 8,000, for example), let's unpack this a little.
Unpacking the results:
If the math makes you queasy, that's fine. I assume most people don't want the math, just the rule they should follow. Unfortunately, there is no simple rule, because the math is so complicated. But, we can get a few interesting tidbits from it:
The heavier your ship is without any cargo (the fixed weight), the earlier you should be adding cargo racks
If your galleon is very light (no fixed weight), the you should add a rack if you have 15.6% of your weight capacity in free weight. For a stock ship with 30k lbs capacity, this would be about 4,700 lbs of cargo. Of course, this assumes you have all your other racks filled already.
Here is a graph comparing the speed of a ship with optimal use of cargo racks versus no use of cargo racks. The flatter sections show where racks are added (for a default galleon with no fixed weight):
This may feel a little underwhelming, but you can get much more accurate numbers if you actually compute the free weight from the equation above. As a note, the amount of free weight needed changes with the number of racks on your ship, so it will change as you add more and more cargo. I suggest you add a sign on your ship, noting the ship capacity and fixed weight right after you make it, and then keep track of when you should add each of the 6 boxes on another sign.
What is the optimal way to haul resources long distances in as little time as possible?
This is another very complicated question. In addition to the problem of the cargo racks (addressed thoroughly above), you now have the added complexity of changing your goal. There are (as far as I can see) 2 main goals when it comes to hauling resources:
Haul as many resources as possible in a given amount of time. This usually occurs when you have a supply route and you will keep making return trips indefinitely.
Haul a given number of resources in the shortest time possible. This usually happens when you are trading or want to go on a relatively small-scale resource expedition.
For the first goal, you want to minimize the time spent on each pound of resource, so you can move as much as possible with the time you have. For the second goal, you are trying to minimize the total time spent, which is not always accomplished by moving the fastest at any given time. This is more complex. Let's look at each one individually:
Hauling indefinite resources in a given amount of time:
If you haul more at once, you move slower but get more across in one trip. If you haul less, you move faster but get fewer resources in one trip. We also have to consider that half of the time you are sailing, you are just bringing the empty ship back to the resource location. This means that the fixed weight of your ship makes a big difference in the optimal strategy. If your fixed weight is high, you should haul more cargo to avoid making many trips. If your fixed weight is low, you should haul less and move faster, since the wasted time on the return trip is quite small.
Working through some of the math, I made some plots for the item transfer rate versus the loaded ship weight (with optimal cargo racks). Here they are, and we will discuss them after:
It turns out that for 0 fixed weight, you should carry 12,530 lbs to be most efficient, and for 10,000 fixed weight, you should load up to 19,600 lbs. However, you can see from the 10k fixed weight graph that it may be possible to improve the efficiency further, since the cargo racks are optimized for speed, not item transfer rate. Specifically, adding the last cargo rack earlier would translate into extending the rightmost section of the graph further to the left, where it looks like it may reach a higher rate than this optimization allows. This is an area that can certainly be improved in the future.
In general, you should load your ship up to about 50% of the way between the empty weight and the full weight to get the most efficient run. It can get better than that, but this will get you a majority of the way there, if you use your cargo racks optimally. Not much else to say here, that is the main rule-of-thumb of this section.
Hauling a fixed amount of resources as quickly as possible:
The goal here is just to minimize the time taken to get the resources back. Since speed drops off quickly as your ship fills up, the strategy will be to split the load up into equal-sized portions and take the same amount of weight each trip, so you avoid a few heavy/slow loads. Then, since every trip takes the same amount of time, we can just optimize each trip. However, the optimal weight HEAVILY depends on the amount of cargo you want to haul back. Look at the next graph (of optimal haul weights versus the target weight you wish to carry back), and let me know if you can make any sense of the chaos:
One bit of information to be gleaned from this mess is what happens when you need to haul a LOT of cargo. The chaotic mess converges to the same number that we got for the case where we wanted to haul an indefinite amount of cargo at as fast a rate as possible. Here is a zoomed-out image of the same graph I just showed.
Obviously this behavior is much more complex than the behavior when you just want to maximize the rate. Therefore, I suggest that you just follow the advice there and let this section be more of a curiosity than actual advice. I mean, if you want to calculate the optimal carry weight every time you want to haul cargo, be my guest
Here, I will just list a bunch of bullet points that summarize the findings throughout the rest of the guide:
As weight increases, your ship speed will fall faster and faster. Therefore, you should aim to keep your ship at around 50% capacity as a rule of thumb. This balances the amount of cargo you are hauling with the speed decrease from the additional weight.
Galleons are the fastest ship in the game, followed by schooners, and then brigantines, and sloops are the slowest. When you are putting sails on these ships, start with the largest possible sail and fill in smaller sails afterward, to get the fastest sail configuration.
As a rule of thumb, add a cargo rack when you have 4,000 pounds of resources available to store in it, and always fill up any existing cargo racks as much as possible.
The heavier your ship is without any cargo on board, the earlier you want to add cargo racks when filling up your ship.
The perfectly optimal weight arrangement is very complicated, and depends on many factors. You can look through the rest of this post for more info, but just know that these rules-of-thumb may not always be suitable for your exact scenario, and you'll need to use a bit of common sense.
Thank you for reading through this quite long guide. If you didn't understand a part of it (or any of it), I will be keeping up-to-date with the comments, so feel free to ask any questions there. If you have any ideas you want me to look into further, I am open to suggestions for another guide. If you liked this extremely thorough type of guide, please let me know, so I can be motivated to make more in the future.