How to build a boat that lasts centuries?

Hey people,

The boat I am building is not physical, it's for a story.
The requirements of my "boat" are:

• Long-lasting. The longer without corrosion the better, it will be docked, maybe for centuries. This is what I found about metals: https://en.wikipedia.org/wiki/Galvanic_series maybe a non-metal is even better, I don't know. Right now I'm thinking about titanium or stainless steel, but I have no clue how long this survives submerged.
  
• It also needs to survive natural disasters like floods, right now I'm simply thinking about an anchor with a long chain.
  
• Stealthy. It needs to be able to go under the radar.
• It is constructed somewhere mid 21st century, so near future.
• Budget is extremely high but not unlimited, so price/quality ratio should be kept in mind.

I hope this is not too rude to ask, but I have zero knowledge about boats. If this post is not in the right section I'll be happy to move it (or get it moved).

 

Ferrocement will show clearly on a radar. For stealth you need material that are either transparent to radar, absorb the energy of the radar pulse, or both. The design and materials will depend on the conditions the boat will be in. For example, a tropical environment will increase corrosion or other chemical reactions, and there may be damage by biologicals. If the boat will be in the polar regions, ice and damage by freezing may be the biggest problem to address. Weather conditions are also to be considered. For example, any mooring attachments (rope, chain, etc.) is likely to wear and break in less than a century.

 

I'd say some kind of fibre-reinforced plastic would have the potential to last beyond a century. Plenty around that have gone the half-century with little or no deterioration of the FRP......the other materials, principally timber, used in conjunction, would be corrupted by rot and corrosion.

 

Regardless of hull material (monel would be my choice), marine growth will eventually hole and/or sink the boat. Imagine a boat that is sitting in the water for generations. We have many of these around the world and a layer of marine growth is encrusted on all underwater surfaces. In the case of some light ships, which have been in the water continuously for 100 or more years, the growth is measured in feet, not inches. These have survived floods, storms, etc., but not without some damage, repair and upkeep, which is the real issue, not hull material choices. If you want to survive for generations, you'll have to maintain the vessel. Not even stone cliffs can take on mother nature's wrath, without getting the crap beat out of it. Maybe in the next century, materials innovation will come up with something that is all but impervious, but currently, nope, nadda, zip . . .

A good look at the remains of Titanic is a good case study about what happens in the sea. After 100 years, the huge mass of this ship is nearly completely melted into a rusted mass, with little resemblance of what it was the day she sank. In fact in another 20 years, it'll be hard to tell she was a huge ship at all, as the current rate of structure collapse has been accelerating.

 

Polyethylene is said not to hold marine growth, but whether that lasts indefinitely.....I know not. UV light probably kills it before the century arrives.

 

I used to have a polyethylene jon boat and it did resist growth, but still got it, it took longer. You're probably right in that it will depolymerize from UV in much less than a century, let alone several.

 

It is hard to make anything, from a material that has the potential to return to its native state, that lasts indefinitely. Stone buildings last, because the material was already in a stable form and had lasted vast lengths of time. Iron and aluminium do not exist in nature, other than in an oxidised or otherwise chemically combined form. Timber rots, if it did not, the natural world could not function. Plastics are organic substances that are subject to breakdown from UV light, but in combination with stable re-inforcements, and heavily pigmented to counter UV, probably a good candidate to exceed 100 years.

 

It is hypothetical, so you can use a material that does not (yet) exist, like artificial shark skin for the wet side of the hull. Stealth can be achieved by a proper shape with flat surfaces that reflect a radar beam away from its source. Tempered glass seems the best choice to me.
There should also be a long lasting power source to keep the ship dry and defend it against vandalism or piracy. A thermo-electric generator with slowly decaying radioactive material can provide electricity almost indefinitely.

An interesting topic!

 

Make it out of silver, and damn the expense ! Does silver resist marine growth ? If it sinks, it will be worthwhile to salvage.

 

NO!! Dilithium crystals is the way to go.

 

This is very helpful. A lot of the discussion seems to be about the hull which is probably good since it probably is the hardest part? But I also have concerns about the mechanisms that might age poorly, like the engine.
For stealth does material matter or is it mostly shape? Is see here that for submarines color appearantly matters, is it the same for boats/ships?
Would it be better to make it a sailboat? It's docked on an abandoned island so no worries about vandalism or theft. Storms, heat, cold, climate change on the other hand is something to think about.
I have some ideas for the hull but they may be unrealistic.

• Polyethylene with a small layer of gold on top (to protect against UV like NASA does). Same goes for any other hull that's great but not so great against UV, cover it with a layer of gold. (here is some eye-candy I found)
  
• Like Mr Efficiency says, silver. Will that last? I read here that silver does corrode and rust, gold does not.
• I see no one has mentioned fiberglass, not a good choice?
• Is it possible to keep the boat in a space where it does not corrode, rust, no matter the material?

Thanks for all the help until now, it's great!

 

You're thinking of a different kind of ship to trek on

 

Jokes aside, an iridium allow would be very corrosion resistant. You wouldn't need to specify the exact composition or heat treatment. As with dilithium crystals, they fulfill their role in the story. Also, it could be docked through magnetic forces, where there is no wear and tear.

 

I think as the writer, you should already have a reasonable idea how to pull this off. Inventing new, seemingly innocuous terms for new materials, possibly incorporating bits of root elements (Trilithium, for example, or maybe homogenized tungsten).

Yes, stealth is more than shape, but also an absorbent coating (and other stuff). I might add that radar is likely a passing technology, with replacements quite capable of picking up, a stealth fighter with little difficulty. Communications will dramatically change, as will social and economic realities. This might be the better approuch to focus on, less the technical aspects of such a ship, but the geopolitical, economic and social changes that will occur. Such as; will cybernetics be taken to extremes or will laws be necessary, to limit how much "enhancement" can be performed. For example, given the potential advances in another two or three decades, you can't just about bet the military will have a battalion or two, growing in a under mountain laboratory, having been chemically, genetically and cybernetically enhanced to produce the perfect soldier or even worse the age old attempt, for a man made beast of burden. Of course there's AI awareness issue you can play with. Do they get personal freedoms and liberties?

 

I don't fancy coating polyethylene with gold would be that easy ! You might use it as the pigment in the poly.....hopefully not much is required to get the UV blocking......otherwise you will (A) Go broke, or (B) have a boat so heavy, it will sink to the gunwales !