My magical civilizations have a unique type of magic, material magic. This magic allows them to improve strength and hardness of wood. As an example: with a cannonball, the magically treated wood offers protection against penetration of ~2 times the thickness of normal wood. (As for use of bamboo in ship building, it can also be magically refined in a same way).

What we're working here with are pre-industrial age of sail ships, things like Western carracks (something like Mary Rose)/possibly early galleons and Eastern djongs/junks (Chinese treasure fleet). I understand that my material improvement might allow slightly larger ships, and that they will also be able to carry more cargo. Warships will be able to take more cannon beating. Perhaps there are some other things that I've missed, but I assume the change isn't too drastic, it just shifts the qualities of ships slightly in the direction of iron ships. I'd welcome a correction if I am wrong though.

There however is another important thing to consider. My material magic also allows woodworkers to join/connect wood, as if it was always one piece. No need for nailing planks together, and the end result is that ship is as if it was carved out of a single tree, even though it wasn't. As far as I know, medieval ships size were very dependent on tall trees, and I cannot imagine how the ability to connect pieces of wood like that would change limits of shipbuilding.

So, I need to ask, how would such magic ability change the warships built? How would this impact things like size and design of such warships?

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    $\begingroup$ The vast majority of medieval war ships were galleys. Carracks were merchantmen, not men'o'war. The Mary Rose was built in the Renaissance, not the Middle Ages. I don't know of any important naval battle in the Middle Ages where cannon played a significant role; I'd be happy to be given an example. $\endgroup$
    – AlexP
    Jan 19, 2020 at 23:56
  • $\begingroup$ OK, I will rework the question. I wanted to avoid using term Reneisance (as that is solely ours, European, thing), but failed to notice Reneisance is already treated as outside of the Middle Ages. @AlexP PS: Edit finished, is this better now? I used pre-industrial instead of medieval. $\endgroup$ Jan 20, 2020 at 0:00
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    $\begingroup$ Join the club... I also had the same impression, no doubt instilled during my (apparently now obsolete) primary education. But it does indeed seem to be the custom nowadays to treat the Renaissance as a separate period of its own. $\endgroup$
    – AlexP
    Jan 20, 2020 at 0:03
  • $\begingroup$ It might help other users answer your question if you went a bit more in-depth with exactly how this material magic works. What properties of an object can this magic affect? Is it only hardness, or can it also manipulate density/weight, plasticity, other things? If your magic can only affect hardness, then you might have a bigger boat. But if your magic also affects density, you're going to have cannonballs and other projectiles that have penetrating power upgraded to match the blocking power of a ship's magically enhanced hull, for example. $\endgroup$
    – KaiGuyMBK
    Jan 20, 2020 at 7:05
  • $\begingroup$ No density manipulation. While the process is magical, the result is absolutely non magical wood, which is simply harder. Density increases, but only slightly (5-10% at most). The effect is similar to wood densification. @KaiGuyMBK $\endgroup$ Jan 20, 2020 at 7:15

5 Answers 5


I have a few things to note that have not yet been covered in other answers.

  • Flexibility: traditionally, wooden shipbuilding used a time-consuming process called Steam Bending to temporarily soften pieces of wood in order to plastically deform them into the necessary curved shapes. If a mage can do that faster with magic, construction could go substantially faster.
  • Structure: A ship's frame bears most of the forces the ship is subjected to. In theory a hull could be made thick enough to withstand such forces, but to do so in our reality would require so much extra wood and add so much extra weight that it's never done. Instead, hulls are made as thin as is practical given the conditions they will face (coastal and river [brown-water and green-water] ships can have thinner hulls than high-seas [blue-water] ships, trading ships can have thinner hulls than warships, et cetera). The hull is mounted on a complex structural frame that attempts to maximize strength while minimizing weight. The complexity is partially caused by the fact that wood's strength against any force varies greatly by the force's orientation relative to the grain, and thus the frame is made of many short timbers arranged to be in the best direction for the stresses each will endure, and braced at the joints with more timbers that distribute the stresses across the entire frame rather than letting it concentrate at a single point. In your world, however, the ability to seamlessly fuse pieces of wood to the extent of joining their grain structure allows you to do away with a good portion of this structure and make your ships lighter and more spacious for the same strength. The densification helps with reclaiming a bit of interior space as well. You still need extensive bracing fore and aft and beam to beam to resist buckling, bending, and twisting, but not nearly as much. Care does still need to be taken with the directions of the fused wood grains, as mentioned. The hull would benefit by having layered grain structures orthogonal to each other for maximum pressure resistance - you could produce something like a Monocoque made of a fusion of Marine Plywood and Cross-Laminated Timber, which would let you have even stronger hulls for the same weight.
  • Failure modes: the Strength of Materials involves more than hardness. You said that the magic system can improve wood's Impact Strength, but you also want to figure out what your magic can and cannot do in terms of Compressive Strength, Tensile Strength, and Fatigue Strength. Under normal conditions, wood cracks when any of these strengths are exceeded - and the more force it took to reach the breaking point, the more dramatic it will be when that force is released.
  • Fire resistance: Densified wood tends to char rather than be consumed by fire, which will help limit the spread of shipboard fires. Ropes and sails will still be extremely vulnerable, unless your world includes some way of fireproofing them as well.
  • Masts and Rigging: Mast failure by bending and ultimately cracking (known as a "sprung mast" if it doesn't just snap off completely) became a major problem as ships got bigger and got more sails, which put extreme strain on the masts. In our world, this was combated by adding extensive webs of "standing rigging", strong ropes that ran between the top of a mast and the frame of the upper deck in the same way that a modern radio tower is supported by guy wires. As masts got ever taller and the forces on masts became ever greater, even extensive standing rigging was often insufficient, and it became common and then standard for masts to be reinforced by wrapping them at intervals with tightly-coiled rope and/or iron hoops. These helped keep the wood fibers from separating under bending stress. With your magic, it sounds like it would be feasible to clad a vertically-oriented core with a layer of horizontally-oriented fibers joined into complete loops, which should offer comparable strength increases. There is also the potential of magically joining wooden beams horizontally between masts to add support in compression (compared to rope, which is only strong in tension) and diagonally from frame to mast to act as buttresses.
  • Biofouling: All ships and boats (and any other structures in the water), no matter what they're made of, are subject to the buildup of a layer of aquatic life including seaweed, algae, barnacles, tube worms, and hundreds of other species. This rapid buildup makes the surface increasingly rough, causing turbulence and drag that can slow a ship by up to 10%. Ships need to regularly undergo maintenance to clean their hulls and counter these effects. Wooden ships also have to deal with Shipworms, a group of molluscs that bore into - and eventually destroy - any submerged wood. The only effective long-term protection against shipworms in our world has been to fasten copper sheathing to the hull up to the waterline (which also conveniently reduces biofouling, but inconveniently prohibits the use of iron nails as it hugely accelerates their corrosion). Other metals like lead and iron are notably heavier and corrode quickly, making them impractical. A sacrificial non-structural layer of wood was sometimes used, which temporarily shielded the structural hull from damage and needed to be replaced frequently. Various toxic coatings have also been used, but they pose a health hazard and need to be reapplied frequently to maintain their effectiveness. Anything magic can do to ease this problem will give any navy with magic a substantial advantage over any without.
  • Cost: This magic has the potential to drastically reduce the cost of building and maintaining a ship, especially with regards to time. Doing away with nails will save a huge amount of money and time (as @Kepotx says, nails are very time-consuming to make without industrialization and/or metalbending, and sometimes a ship would need to have its hull completely disassembled just to replace corroded nails before the bottom of the ship falls off). A less complicated frame cuts down on construction time significantly. Being able to manipulate "living material" strongly implies the possibility of magically removing biofouling, and unless such magic is itself time-consuming and difficult/rare, it would almost certainly be easier than having to manually scrape off the fouling. If that defouling can be done from inside the ship, without needing to careen it or use a drydock, the time and effort savings would be enormous, as it could be done without taking the ship out of service at all. Repairing a ship, as @DarthDonut mentions, will be a much smoother process as cracks can be directly mended and holes can be patched without having to remove and replace damaged planks. Faster repair means greater reliability and less time out of service. Being able to turn small pieces of relatively low-quality wood into a single long, uniform, high-strength beam means that masts can be made from whatever trees are nearby, instead of needing to find trees with the desired height, thickness, and straightness, and again saving time and money.

Further Reading:

The Mechanical Properties of Wood (1914), by Samuel J. Record [Unrestricted webpage and e-book] - Details the strengths and weaknesses of wood under mechanical stress.

The Structures of English Wooden Ships (1993), by Trevor Kenchington [Unrestricted PDF] - A description of the structure and construction of English ships circa 1710, based on a contemporary book written by William Sutherland after a career in the Royal dockyards, particularly at Portsmouth and Deptford. Walks through the entire structure of a three-decked ship-of-the-line.

Illustrated Glossary of Ship and Boat Terms (1994), by J. Richard Steffy [Unrestricted webpage and PDF] - Provides definitions, descriptions, and illustrations of the nautical terms used in Kenchington's paper, among many others. Excerpt from Steffy's book Wooden Ship Building and the Interpretation of Shipwrecks. Published as part of The Oxford Handbook of Maritime Archaeology, most chapters of which are restricted to online subscribers and people who buy the book [Restricted e-book, hardcover, or softcover] but which also contains a great deal of additional information on ship design throughout history.

History of Masts, from the National Museum of the Royal New Zealand Navy [Unrestricted webpage] - Provides details of mast construction

The Elements and Practice of Rigging and Seamanship (1794), by David Steel [Unrestricted webpage] - Provides extensive detail on all aspects of a ship's rigging, including ropes, masts, sails, anchors, and blocks (pulleys), as well as detailed descriptions of seamanship, the practice of working ships, and naval tactics.

The History of the Prevention of Fouling (1952), from the U.S. Naval Institute [Unrestricted PDF] - Explains some of the methods that have attempted to counter biofouling, for both wood and metal hulls.

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    $\begingroup$ Thank you for your response as well as for all the literature recommended. Both are very helpful to worldbuilding my magic navies. I've already put a lot of time in studying all the basic information I could find, so I'm thankful for recommendation of any reading with extrensive details. $\endgroup$ Jan 20, 2020 at 22:03
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    $\begingroup$ @FailusMaximus Glad to be helpful! I hope I can read the story this is for when it's done; that kind of magic has all kinds of potential uses! $\endgroup$
    – Lawton
    Jan 20, 2020 at 22:15
  • $\begingroup$ Definitely. I'll just have to force myself to write myself out of the block. $\endgroup$ Jan 20, 2020 at 22:40

On which parts of a ship could this magic be used?

  1. The hull: Ships during the Age of Sail had always the problem with water coming in through small gaps in the woodwork of the hull.
    A fused wooden hull would be (nearly) completely waterproof, and as such reduce the need for bilge pumps. You won't remove them completely, because you need them in case of hull damage and storm water, but you won't operate them 24/7.
    The stability of the hull would be better than traditionally build ships, because at the end of the process your hull would be a single fused piece. With this in mind, your ships could weather storms better, and would be seaworthier than normally built designs.
  2. Ropes: Most ropes were made from hemp, and as such it should be possible to strengthen them. The result would be something along the line of sturdier ropes that don't break as often.
  3. Mast: As Henry Taylor pointed out in his answer, the mast height could be improved as far as the ship would not become top-heavy.
  4. Sails: Made from organic material, the sails could be reinforced like the ropes and as such be made thinner or bigger. They would not tear as easily, reducing the needed repairs.
  5. Repairs: Say someone put a hole in your ship. Say you have a mage on board. Depending on how this magic is applied, you simply take a wooden board, put it on the hole, the mage sings, dances or puts his hands on the wood, and vóila! Repaired hull. One could also go as far and use sawdust to patch things up by mending the dust to real wood.

To conclude: Your ships would most likely become lighter(and thus faster), bigger, sturdier and easier to repair in comparison to your mundane rivals. Soon you will reign supreme on the seven seas!


Greater mast heights (from joining the lengths of multiple trees) and greater mast strength with no increase in weight should provide more wind catching capacity and therefore greater cruising speeds. Doubling the hardness of the hull would also increase the effectiveness and safety of ramming other vessels which lack the wood magic.


Easyer maintenance

TL;DR: no need to replace the nails anymore.

Other answers already cover how a stronger wood make a better ship.

But the construction, or repair on plain sea is not the only thing you should care about a ship, there is also maintenance, and your magic wood will help it. Also, a better wood is not the only advantage, there is also the lack of metal nails.

My material magic also allows woodworkers to join/connect wood, as if it was always one piece. No need for nailing planks together

This, is a great advantage. I once visit albaola, a place where they rebuilt the san juan, a ship from the 16th century. One interesting part was the cost of the nails. Today, a nail cost only it's weight on metal, but is easy to make. However, it's much longer to do it with pre-industrial technology. This will save you a lot of time/money for the construction, but not only.

Nails rust. You need to replace them quite often. this almost means you should re-create tons of nails, and replace each of them, basically rebuilding the ships. Treenails (nails of wood) were also used, but they can't always replace nails.


Cost and locations of Construction:

One of the biggest impacts that being able to magically work wood for a ship building industry is going to be a vastly reduced cost to build, as well as opening up far more regions to effective Big Ship industry.

While large trees would probably still be prized for their prestige and reduced wood-mage labour requirements, regions with smaller trees could still produce larger vessels while having less risk of industry collapse due to over harvesting.

Rate of ship production becomes more like modern pulp and paper industry: How much land can you have around a shipyard, and how much 'reasonable growth' wood product can you harvest off it in 20-40 year cycles.

Your labour can focus on lower skill wood harvesting and working as well. Handling and shipping wood off a 30 year old tree, which you can cut into lengths short enough for a single man to pick up on his own, takes far less skill and effort than cutting and handling 500 year old growth...

Large ships can then be built out of material cheaply harvested and carted around, rather than relying on heavily specialized material handling. It becomes little more effort than moving local firewood stocks, rather than sending colonists off to far flung reaches of the earth in search of specific old growth lumber.

However, without improvements to propulsion methods, you are unlikely to see an impact of ships much larger than we had at the end of the age of sail with iron hull vessels. They simply become too hard to handle safely in open ocean conditions, and while shuffling around in ports.

  • $\begingroup$ You won't see significantly larger ships because of hogging. The right wave conditions can cause modern steel framed and hulled ships to break their backs. $\endgroup$ Jan 20, 2020 at 17:56

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