Warship design to sail on quicksand?

Question

I want to make a world where there's no rivers or oceans but instead they're replaced by quicksand or similar. People get water from rain and water springs or wells.

So I want to create a warship for their naval battles, either to yaarrghh plunder the booty or invasion. I think a bridge is too predictable, and can easily be cut off or blockaded, and creates a bottleneck to the invader unless they widen it, and I don't know how much it costs to make a bridge to cross an entire ocean compared to ships, or whether it can withstand wagons or mounted animals crossing, but regardless, I want to make a naval battle with warships, even if portable bridges like pontoon bridges and similar would be possible or cheaper (so even if you bring that up, please also include regarding the ship design).

• The size of the warships are variable, but for simplicity's sake just assume they are as big as galleon ships.

• I think the ship bottom should be flat like a raft in order for it to float, but I am not sure so correct me if I am wrong.

• The ship is in a wind sailing era so no steam power or wheel paddle, if wind is not sufficient to make it move please include how many people need to row it or what type of sail can achieve it (originally I want to use junk type of sail) or the numbers of sails, and it's OK if the answers say there's no ship design with that size that can sail on quicksand too, at least I know a raft can sail on it so small ship warfare is at least feasible for me (but correct me if I am mistaken).

• It's a wooden ship, so no weird shape to accommodate better sail in quicksand from metal shaping.

• And since this is warship, I am worried regarding the cannon fire or where to place them, or if it's far better not to use cannon at all, since I think the recoil may make the ship capsize or sink or get in deeper due to the shaking.

I also considered including waves for the quicksand ocean (not decided yet, so you can ignore it) but I am not sure if a normal ship can float in it, since I saw some video about sand waves that it can sink many things, but correct me if it's possible for ship to float.

If possible please also include the math, since I am not good with math, and sorry if I make lots of misconception or the answer turns out to be obvious, I am not that knowledgeable about ship design, and my physics knowledge is at best similar to stone age level.

Answer 1

Quicksand is a non-newtonian fluid which means that it acts differently than a normal liquid when force is applied to it. Typically that means it is like a liquid when low forces are applied (e.g. standing) but like a solid when high forces are applied (e.g. hitting).

Your ship probably doesn't want to "float" in it, being under the surface of the quicksand will severely limit your speed (faster = high force = more solid). Instead you want to 'walk' on it, repeatedly applying high impact "steps" on the surface. Something like a "stamping centipede" with lots of legs that stamped up and down would work well.

You would have to be careful you ship never stopped though! If it started to sink it would be very hard to pull itself back out again. There's a neat video and explanation, which shows people happily running on a cornstarch pool, while one person who stops gets totally stuck! https://owlcation.com/stem/Oobleck-Quicksand-Cornstarch-And-Water

Answer 2

Sail powered airboat.

First principles: you do not want you boat to extend down into the quicksand, which would offer too much friction. The boat therefore will need to be completely above the quicksand.

I was thinking of something like a fanboat or airboat - flat bottomed boats powered across marsh and mud by a large fan or propellor. It would seem that these emerged only after motorized aircraft were invented. If there was a sail powered flat bottomed boat for marsh use prior to fan boats I could not find it. I think all boats for marsh use were paddled and mud flat / quicksand was not accessible.

But there were and are sailing barges.

https://en.wikipedia.org/wiki/Thames_sailing_barge

The flat-bottomed hull made these craft extremely versatile and economical. They could float in as little as 3 ft (0.91 m) of water and could dry out in the tidal waters without heeling over. This allowed them to visit the narrow tributaries and creeks of the Thames to load farm cargoes, or to dry out on the sand banks and mudflats to load materials for building and brickmaking .... The main mast could be lowered to clear bridges. Furthermore, unlike most sailing craft, these barges could sail completely unballasted — a major saving in labour and time.

We will crossbreed a sailing barge with a skimboard. https://www.wikihow.com/Skimboard

Skimboards are flat rudderless planks. One runs up, and jumps on the skim board, then is usually powered by momentum only. Some people can kick like on a skateboard.

---

The result is a Thames sailing barge with no draft at all - it is flat. There might be a cabin or walls. It is no longer able to carry heavy cargo but it keeps the giant sails (and they are still red) because it needs great propulsive force - comparable to an airplane propellor - to overcome the friction of the quicksand. Unlike a fan boat the sail also provides lift which reduces weight.

These things will need to be moving fast or they risk getting bogged down. High / dry points will also be risky. Probably there will be poles for the crew to pole the ship off if it gets lodged in dry sand.

Low wind means the quicksand ships sit and wait. That would be a great scene for your story. The pirates are becalmed in the quicksand. They look like sitting ducks. But how to reach them?

Answer 3

Consider something like a catamaran or outrigger, which will function more like a sled than a boat. The less of your craft that sits in the sand the better as it will have much higher drag than water.

Lets be clear your sea can't exist and even if it did no ship could sail it without being worn away in days so you need a fair amount of handwavium to work.

Craft like this are already used on snow. There are a variety of styles out there so you can even have various cultural styles. They also exist in a wide variety of styles and materials including modern steel warships.

You can also find plenty of art with takes on this concept for a sand craft, in real life the abrasiveness of the sand will wear and ship away in no time, so you already have to be hand-waving friction, but at first glace this at least looks like it might work. If you want to make it slightly more believable make the skids out of some part of the native wildlife that naturally swims through the sand, that way it can reflect whatever magic allows a sea of quicksand to exist.