So, in the age of sail, there where hundreds of dangers lurking in ships, mostly in the form of sickness such as scurvy, and I'm looking for a way to have sailors in a similar technology level as healthy as they'd be in mainland.
More specifically I'm looking for a solution for these four problems:

  1. How to keep sailors from malnutrition?
  2. How to treat common diseases skillfully?
  3. How to keep sailors reasonably clean?
  4. How to keep food from rotting?

While there is magic in this world, and it plays a significant part in naval history, there are simply not enough mages to go around using magic to fade away all of a ship's problems. For instance, while having a mage refrigerating the supplies of a ship, thus keeping the crew from malnutrition, the food from rotting, and avoiding many diseases, most ships simply won't have anyone "magical" enough to make such things happen, so for all intents and purposes, discard magic.

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    $\begingroup$ How much advanced knowledge (like microbes) and technology (like pasteurization and canning) is this civilization likely to develop with magical help? You don't need mages on the ship to refrigerate if ones on land invented the microscope and the statistics for epidemiology. $\endgroup$ – user535733 Dec 4 '17 at 1:31
  • $\begingroup$ Excellent question! In actual medicine, the civilization would be somewhere in the late 17th century, so they barely know anything about microbes, but now that you mentioned it, pasteurization is clearly within the bounds of the magical / technological knowledge of this civilization. Canning is good to go to, in a very primitive manner though, like it was during the times of Nicolas Appert, but I believe that these two make a very good solution! Thank you! $\endgroup$ – Jedboo Dec 4 '17 at 1:46
  • $\begingroup$ that also solves 1 as well, bring canned fruits and vegetables. $\endgroup$ – John Dec 4 '17 at 1:59
  • $\begingroup$ Oh yeah, didn't see that, thanks for the heads up! $\endgroup$ – Jedboo Dec 4 '17 at 2:06
  • $\begingroup$ @Jedboo "like it was during the times of Nicolas Appert" you're confusing the 16th century with the 18th century. $\endgroup$ – RonJohn Dec 4 '17 at 7:40

10 Answers 10


I seriously doubt it is possible to keep your sailors as healthy as on the shore with Renaissance technologies. Especially, if they are at sea for months. But it is still possible to prevent them from dying.

1. Malnutrition prevention

As others mentioned, food preserving and canning can provide sailors with vitamins. It is better if preserving done using non-heat or low heat techniques to avoid loss of micronutrients. If preserves contain any liquid it must be consumed and never disposed of. This is especially important for scurvy prevention since vitamin C is water-soluble and tends to leach from foodstuffs into the water.

It is important to prevent oxidisation which is the main reason for the loss of nutrients. So, you need to be able to store food in airtight containers preferably in such a way that contents of each container can be consumed within a day or two.

You also need to pay attention to the price of preserves. Hard bread was very popular (and was the staple of sailors diet) not only because it stores well, but also because it is very cheap to produce. It is essentially flour and water. Sometimes just a sprinkle of salt was added to improve taste. (Although the recipe is quite simple, the preparation was not and could take as long as several months.) Most of the food preservation techniques available at the time involved salt or fermentation. Salt was not cheap. So, it was not economically viable to have large quantities of high-quality preserves on a ship.

2. Healthcare

In order to prevent common diseases and treat them, you have to have doctors and some pre-established knowledge of those diseases. Some form of a primitive germ theory would be a great help. It would allow establishing simple but effective disease prevention procedures such as boiling water and quarantine.

Ship cleaning is essential for keeping the crew healthy. It is also a perfect excuse to keep them occupied. It is better if sailors understand that a clean ship equals better health.

Living in close quarters (and there is no way around it on a ship) on its own creates health risks. Physical risks such as the rapid spread of infections are obvious. However, psychological health is even at a greater risk. So, any ship would greatly benefit from having a priest or a morale officer. Some form of recreation (including sparring or any other physical activity) would reduce occurrences of brawls by providing a way to react on aggressive impulses without resorting to a mutiny.

3. Hygiene

Modern Western sensibilities and daily showers have no place in a Renaissance setting. Neither they are practical nor particularly healthy. Frequent showers strip moisture from the skin and by drying it make it more susceptible to microbial infections. It is also not possible to carry enough fresh water for showers. However, one of the ways to keep reasonably clean is to use baking soda, vinegar, and wet rags.

For those wondering about practical uses of baking soda and vinegar

Sodium bicarbonate (baking soda) is a mild disinfectant. A mix of water and soda (usually as a thick paste) can be used to disinfect various surfaces. Baking soda also has some fungicidal properties. If mixed with oil or water baking soda can work as antibacterial soap (but do not expect it to kill 99.9% of all known germs). An additional benefit of such a soap is the elimination of body odours.

Sodium bicarbonate has many other useful applications: 1) cooking (as leavening, aka raising, agent); 2) teeth cleaning; 3) laundry detergent; 4) rust removal; and even heartburn treatment.

As @RonJohn mentioned in comments sodium bicarbonate was not available in pure form until the 19th century. If it is the case in your world, you can replace it with natron. It's a naturally occurring mixture of various salts available almost on all continents. I am not sure it will be edible, but it will still work as a great cleaning agent (as proved by Ancient Egyptians).

Vinegar is a mild acid with antimicrobial properties. Aside from its uses in culinary, vinegar is good general purpose cleaner. It is especially effective against salt build-up (cleaning mirrors :)). When it comes to personal hygiene, vinegar is frequently used as a hair rinse (about one tablespoon for a couple of litres of water).

One thing you should be really concerned about is laundry. Keeping clothes and linens clean is paramount for keeping sailors healthy. Unlike our bodies that have all kinds of protection against infection, clothes and linen have none. Therefore they become breeding grounds for insects and bacteria. It is not practical to have a real wash while at sea. But regular airing and exposure to the sun will work as well. UV light from sun sterilises cloth. Airing and shaking mechanically removes loose particles of dirt and skin.

You also want to keep rats and mice at bay since they carry diseases and spoil food. Keeping rat-hunting animals in combination with daily food stores inspections and cleaning might do the trick.

4. Food Storage

Using food preservation techniques and airtight containers will reduce food spoilage. Rodent control measures will protect dry foods.

Traditionally earthenware jars sealed with wax were used for liquids such as oil, beer, and vinegar. Wooden crates were used for meat, fish, dry foods. Bread and flour were usually stored in sacks made of thick cloth. Water was stored in barrels and was prone to spoilage. Many navies used weak beer and wine as healthier substitutes for water (lower risk of bacterial contamination).

Rainwater was collected regularly. It was used for drinking, cooking, washing, and laundry. Your sailors should do the same. It is the only way to replenish your fresh water supply while at sea. So, some kind of vessels should be within easy reach.

  • $\begingroup$ How could salt be “not cheap” when you’re swimming in it? $\endgroup$ – JDługosz Dec 4 '17 at 7:27
  • $\begingroup$ Hmm, your own reference states «The ingredients for these biscuits included only flour and water. Bakers did not add any yeast or salt.» $\endgroup$ – JDługosz Dec 4 '17 at 7:52
  • $\begingroup$ Indeed, from your reference, «After removing it from the brine, the meat went into casks, with extra bay salt applied to each layer of meat placed into the cask.» (emphasis mine). Bay salt is concentrated seawater, made by letting it evaporate. $\endgroup$ – JDługosz Dec 4 '17 at 7:57
  • $\begingroup$ Thanks for the complete answer my friend, you and many other have solved this question in no time, and I can't thank you enough, it's just too bad that I can't choose more than on correct answer in this website $\endgroup$ – Jedboo Dec 4 '17 at 10:46
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    $\begingroup$ @JDługosz Extracting salt from seawater to the point where it's dry enough to be stored and used as seasoning is a lengthy and relatively labour-intensive process, and there's only so many places where the water contains enough salt (and is sufficiently free of other contaminants) for it to be worth the effort of extracting. Salt was a valuable commodity for much of history; the word "salary" comes from the Latin word for salt because it was expensive enough that soldiers were sometimes paid in salt, and England has numerous towns named specifically for the fact that you could get salt there. $\endgroup$ – anaximander Dec 4 '17 at 12:16

1: Re malnutrition: you can just pluck inventions from later times (for example, sauerkraut to combat scurvy from the mid 1700s) and assert that these practices are commonly used in your time.

4: Preserving food methods stayed about the same up until the invention of canned food in the 1800s. Your sailors would have hardtack, salted meats, maybe pickles like sauerkraut, maybe dried fruit if they were lucky, and grog. Alcohol (as rum or whiskey or gin) keeps well and has useful calories.
They could make confit in Renaissance days - cooked meat (often duck) preserved under fat. I have never heard of this going on ships but if I were on a Renaissance ship I would want some. I actually want some right now. If you had some dry beans (no reason dried beans could not go on a ship) you could make cassoulet.

2: As regards medical treatment you can get way into the weeds with this. The observations and recommendations of Ambroise Pare are a good place to start. The "Father of Surgery" wrote a lot in the mid 1500s and a lot of his recommendations on taking care of sick or wounded men make a lot of sense even today. Also his stories are great.

3: Clean sailors? Clean is overrated. How about have them learn to swim and require them to practice periodically? That would have the added benefit of having them not drown if they fell in the water.

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    $\begingroup$ Thanks for the answers! The thing about cleanness though is that, I believe, the lack of hygiene can bring many diseases, and I also don't want sailors to be smelly, louse-ridden, rotting men by the time they reach the coast, for, you know, aesthetic purposes. $\endgroup$ – Jedboo Dec 4 '17 at 2:13
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    $\begingroup$ 3: you get salt build up. Even if the sailor wipes dry, you just transfer the problem to a supply of towels. $\endgroup$ – JDługosz Dec 4 '17 at 7:23
  • $\begingroup$ Look at the big ocean races ( the volvo ocean or Vendée Globe), the sailors on those can't shower unless they wait for rain and stand in that with a brush and grim determination. $\endgroup$ – Borgh Dec 4 '17 at 9:30
  • $\begingroup$ If you want people to smell nice, have them wash their clothes - the soap lobby only wants you to think you need to shower. Sounds like a conspiracy theory, right? Guess again. $\endgroup$ – user121330 Dec 5 '17 at 1:26
  • $\begingroup$ /smelly, louse-ridden, rotting men/ - Head lice and crab lice hang on to hair, so if your sailors shave their heads and get Brazilian wax jobs that will solve that. Body lice ride in clothes so those need to go too. That salt build up @JDlugosz worries about can be addressed with (scented) body oil. Hopefully these changes will assuage your aesthetic sensibilities? $\endgroup$ – Willk Dec 6 '17 at 16:24
  1. Renaissance medicine, by in large, was detrimental to the health of thousands. I'd avoid it if at all possible! Cures, even from the best trained doctors, were hit or miss and largely based on 1400 year old Greek medicine (not without its merits, mind). Surgery was a little more advanced, mostly on account of the horrific wars going on all the time. Probably your best bet for keeping your sailors healthy would be to pitch the "physician" overboard and hire a military surgeon! Preferably one handy in the magical department. As a matter of general health, I'd suggest also building ships a little airier --- higher decks, some ventilation for the poor sods down below. Old ships are dank, dark & close places. Awesome for growing out all kinds of interesting molds and so forth.

  2. Clean is easy. You basically have a 250 billion gallon bath tub all around you. Bathing in salt water is not detrimental, as it's basically a mineral bath. Sailors live in a moist, salt water wavey environment anyway. An occasional dip in the drink with Davey Jones won't harm any of them and will most likely improve their skin.

  3. Canning in tins? Probably not with renaissance technology. Sealing food in jars may be a way to go, though. Just use a beeswax seal rather than a rubber one like with a standard Kerr or Mason jar set.

  • $\begingroup$ Hey, thanks for the answer, you're right about the canning, I really won't have metal cans sealing food, instead I'll have bottles with beeswax doing that job, as you suggested. $\endgroup$ – Jedboo Dec 4 '17 at 10:49
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    $\begingroup$ Keep in mind that glass bottles will be relatively expensive in this time period. An empty jar isn't garbage, it's a container to be put in the hold to be re-filled the next time you make landfall. $\endgroup$ – Mark Dec 5 '17 at 0:23
  • $\begingroup$ Good point, Mark. Recycling is nòt a new concept! Pottery jars would also work, and have been historically (and in some cases, still are) used to preserve food. $\endgroup$ – elemtilas Dec 5 '17 at 0:48
  • $\begingroup$ @elemtilas Jars for bulk storage are an anachronism. Renaissance (and earlier) people already had a better solution for large-volume storage, which was barrels. The purpose of a barrel is to be a watertight container - and hence also airtight. $\endgroup$ – Graham Dec 5 '17 at 12:52
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    $\begingroup$ You're right about barrels being used for storage. But wood is porous. Gasses (especially the enemy of food, oxygen) diffuse through wood. The thing about canning is that it provides additional preservational techniques: first off, the food is actually cooked inside the glass storage jar. Barrelled food is cooked & transfered. Then, the food is definitively sealed. Glass is non-porous, the metal lid is non-porous, the seal (unless broken or originally imperfect) is non-porous. Canned foods last much longer than barrel stored foods, many months to years, perhaps even a century. $\endgroup$ – elemtilas Dec 5 '17 at 23:30

3. Cleanliness

Baking soda is your friend here (or Natron, if you want something that goes back to BC times). Dissolve some in water and soak your clothes/sailors.

Bacteria can't survive it (I think it's the alkalinity?), so that takes away all bacterial smells and diseases. The only thing left is viral diseases you'd catch from ports, but nothing a bit of quarantine can't fix.

  • $\begingroup$ The tiny (they really were pathetically small) ships would then have to buy and carry heaps of natron in addition to food, water, ammunition, etc. $\endgroup$ – RonJohn Dec 4 '17 at 7:56
  • $\begingroup$ I use baking soda as a personal deoderant, I have a tiny jar and it lasts me about 8 months. You just need a pinch to rub on your armpits and it becomes antibacterial. Washing clothes might take more, but still a little goes a long way! $\endgroup$ – Mirror318 Dec 4 '17 at 8:19
  • $\begingroup$ Hey, that's a great idea, thanks for answering! $\endgroup$ – Jedboo Dec 4 '17 at 10:45


Don't underestimate fresh air. Something like the Dorade box could be rigged much earlier. The relatively low speed of a sailing ship compared to a steamer would require larger intakes, possibly out of sailcloth.

  • $\begingroup$ Simple enough, seems like Leonardo could have invented it! $\endgroup$ – JDługosz Dec 4 '17 at 8:01
  • $\begingroup$ Simple and practical answer, thank you! $\endgroup$ – Jedboo Dec 4 '17 at 10:43
  • $\begingroup$ On a sailing ship, the wind can come from any direction except straight ahead, so you'll need to be able to turn the intake. $\endgroup$ – Mark Dec 5 '17 at 0:25

Battling the scurvy bug

One of the great problems historical sailors faced was scurvy due to the diet entirely of preserved breads and meats. The Brits tackled this by throwing citrus fruits into the shipboard diet, but fresh citrus has limits on how long it can be stored for -- any journey longer than a month or two, and all your limes will be toast by the end of it.

One option would be to create a preserve from the citrus fruits -- preserved lemons are readily preparable from fresh lemon, salt, and spices, and the preservation process leaves the vitamin C in them available as well. This also extends the shelf-life of the citrus from on the order of a month to a year, perhaps more, but requires heavy Mason jars and other such contrivances.

Since this is a fantasy setting, though, you're not as limited by some of the constraints of real world plants, and therefore I propose to you this: a salt citron. Basically, it's a fruiting (citrus or similarly vitamin-C-rich) dwarf tree or shrub that can grow in saltwater-irrigated soils (i.e. it's a halophyte). These would be kept live on deck in pots (you'd only need a handful) and irrigated using seawater, giving the crew a steady supply of vitamin-C-rich fruits. (A more realistic example of such a plant is Tetragonia tetragonoides aka "Botany Bay spinach"; while a leaf vegetable, it still contains some quantity of vitamin C, and is a halophyte to at least some degree.)


It sounds like, in your world, wizards -could- solve all of these problems, but you don't have enough of 'em. In that case, put the wizards in the ports.

Your port-wizards can go a long way to mitigating all of your points each time a boat comes to port, as long as the shipowners are willing to pay the port fee. Perhaps you have a couple of specialized wizards (with associated apprentices for the menial tasks) to handle the different needs of the port.

Malnutrition: Magic up some canned goods, or even some magically-preserved foodstuffs. If sailors arrive with flaky skin and wiggly teeth, magic can fix that, too. Though you might have trouble with skinflint captains abusing this system.

Disease: A port-wizard can be in charge of keeping the docks magically free of vermin and other disease vectors. Ships can moor at the quarantine pier until a port-wizard can clear and/or cleanse them of whatever diseases they picked up abroad. If the ships can leave without communicable diseases, then they won't spread them.

Cleanliness: Okay, so this one might be an issue that port-wizards can't easily solve for months at sea. Unless maybe they can provide magic, self-cleaning cloth. Perhaps you pay them for a duration spell? You might look to other answers for this one. On the other hand, if the sailors are already magically healthy at each port, cleanliness becomes a little less of an issue.

Rotting Food: Magic provisions, as mentioned in the Malnutrition point above.

I guess it all kind of depends upon how your magic system works. But "magic" can solve all sorts of problems, so if you can't get it on the boats, then port-wizards might be the next best thing.

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    $\begingroup$ Well here's the deal, people have more necessities for wizards than ports, so even a single good wizard can't be spared for every port, and even then they wouldn't make a very big difference, but thanks anyway $\endgroup$ – Jedboo Dec 6 '17 at 17:17

Disease Let's talk about venereal disease, which nobody seems to have really dealt with. Aside from the usual suspects of dysentery, scurvy typhus, wounds, malaria and malnutrition there's also syphilis:

What did a pirate endure if he contracted syphilis? The disease has three stages.

Chancres form where contact with an infected person occurred. These often heal, leaving small scars.

Six to eight weeks later, the pirate seemed to contract the flu and developed a skin rash. Doctors often misdiagnosed this stage because of its resemblance to small pox and measles. The patient soon recovered and believed himself cured. During this stage, syphilis was contagious, and the pirate often infected many others. After two years, the disease entered a dormant stage.

The final stage occurred when syphilis attacked the body’s systems many years later. Many went mad or blind before they died.

An early treatment for syphilis came from the native peoples in the West Indies. They used a resin found in evergreen holy wood or guaiacum. The more effective treatment, though, was to administer mercury orally, through a vapor bath, or in the case of pirates, by injecting the medication into the penis with a syringe. A salve was applied to the chancres that developed when first contracted. Since syphilis was more or less an occupational hazard, surgeons treated most pirates over a long period of time. Whether the mercury was ingested orally or absorbed through unguents, it often produced a metallic taste in his mouth that caused patients to salivate. They didn’t complain overmuch since many thought it was just the price they paid for contracting the disease in the first place. Mercury poisoning, however, sometimes occurred. When this happened, the pirate lost weight, drooled, had foul breath and blurred vision, and slurred his speech. He also had trouble maintaining his balance. If the treatment for syphilis wasn’t stopped, his kidneys eventually ceased functioning and he died.

The source that I got this from, this webpage is actually a great place to start with--it covers everything, the onboard med kit, the fact that there very often wasn't a real doctor (which was good, because a lot of treatments were more detrimental to health than not) and the absolute utility of having a surgeon--NOT a doctor on board.

Malnutrition Scurvy was super common, but certainly, even by as early as the late 1400s, it was known that citrus was a treatment (although they did a whole bunch of other terrible things to treat it, like cutting themselves to let out blood). In your setting, the knowledge may be more widespread, and so preserves might be included, with citrus and other carriers of vitamin C. You can even have a goat or something to milk on board, which might help (though pasteurization destroys the vitamin C). There's a problem though--FRESH is key when it comes to vitamin C in this setting. See, it's destroyed by boiling or heating. So RAW fish, organ meat, not preserved, is the way to go. Fruit preserves actually might not have what you need because the process of preserving them might actually destroy everything that's needed. So--growing fresh herbs on board and chewing them, raw, that might help--plucking fish out of the sea and consuming them raw, that might also help. The downside of not cooking things is parasites, and other issues, but...this is the upside.

Cleanliness There were seriously sailors that did not swim. But the obvious solution is salt baths or showers. Other answers here have covered this pretty well.

Rotting Food Well, history has your answer: dried, smoked, pickled, honeyed, and salted foods have been around since before Medieval times..The use of these is actually one of the reasons why sailors got scurvy. Because these processes rob food of essential nutrients.

  • $\begingroup$ Pretty complete answer, and historically accurate, thanks! $\endgroup$ – Jedboo Dec 6 '17 at 17:15
  • $\begingroup$ Vitamin C's melting point is 190˚C (374˚F), which is almost twice as high as the temperature of boiling water. See this thread for more details. Thus, there is no need to keep food rich in vitamin C fresh. It can be canned, preserved, whatever. Moreover, research shows that food preserved soon after being harvested and kept in airtight containers has more vitamins that raw food after some storage and transportation. Oxidation and water are greater threats to vitamin C than cooking. $\endgroup$ – Olga Dec 7 '17 at 4:06
  • $\begingroup$ @Olga "Water-soluble nutrients like vitamin C and vitamin B and a group of nutrients called polyphenolics seem to be the most vulnerable to degradation in processing and cooking. Canned peas and carrots lose 85 to 95 percent of their natural Vitamin C. After six months, another study showed that frozen cherries lost as much as 50 percent of anthocyanins, the nutrients found in the dark pigments of fruits and vegetables. Cooking removes about two-thirds of the vitamin C in fresh spinach" well.blogs.nytimes.com/2013/10/18/… $\endgroup$ – Erin Thursby Dec 7 '17 at 14:10
  • $\begingroup$ @Olga In our time, we have the tech to preserve this stuff, but most of the processes they had available to them at that time didn't. Vitamin C in particular is delicate, and back then, most of the time when things were heated, and preserved, water was involved. If you boil lemon juice, when you are done, there isn't any C left. They didn't have canning as we know it during this time. $\endgroup$ – Erin Thursby Dec 7 '17 at 14:20
  • $\begingroup$ @ErinThursby, The same article states 'vitamin C levels often are higher in frozen produce compared with fresh produce, likely because vitamin C levels can degrade during the storage and transport of fresh produce.' The article they link to says 'Retention of ascorbic acid can vary tremendously in all products, depending on cultivar and processing conditions among other variables.' Carrots are especially vulnerable. However, in general retention of nutrients in higher in preserved foods than fresh food stored for the same time. $\endgroup$ – Olga Dec 7 '17 at 23:52
  1. is really easy, many ships carried doctors.

  2. is tricky bathing requires more fresh water, a lot more, so desalinations (or purification) would be the only workable solution. But desalination is not going to happen without magic because you just can't carry enough fuel to desalinate on a voyage of any length. Bathing in salt water for prolonged periods is not good. you may want to consider magical technology instead of direct casting, modern ships use desalination or purification for grey water.

  • $\begingroup$ Thanks for the answer, I think you're right about doctors, though many of them won't be skilled like the fellow in "Master & Commander". But as you said, There's there's no viable way for a common ship to desalinize water without the constant aid of magic, but still, your answer was helpful. Obs - Also, I think you mean '2', not '4' $\endgroup$ – Jedboo Dec 4 '17 at 2:10

How about one-time magical treatment for each sailor? This will not take an ongoing effort for every voyage, but is done once. The magic treatment is to give the sailor a salt-excreting organ, so he can then safely drink seawater.

  • $\begingroup$ Heh. But if you can do that, can't you solve all of the problems with magical transformation into superhumans? It doesn't seem quite in the spirit of the question. $\endgroup$ – user16107 Dec 4 '17 at 16:17
  • $\begingroup$ Well, there are potions for different utilities, but they're expensive, temporary, and few in number, not to mention that mages themselves are very rare, there is simply no way to have a significant amount of sailors affected by magic. $\endgroup$ – Jedboo Dec 4 '17 at 18:24

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