Question about Ship Tonnage in Star Trek

[SuperSaiyaMan12]

Something's been puzzling me-how come the Prime Universe's Constitution-class and other classes weighs so much (excess over 100,000 tons) even though is smaller and should have less volume than the current Nimitz-class, Enterprise-type, and upcoming Gerald Ford-class Supercarriers?

[Coalition]

Because spaceships don't have to worry about sinking due in water.

Because smaller hulls for the same tonnage are easier to armor.

Because smaller hulls for the same tonnage have smaller shield surface areas and so can have relatively stronger shields.

Because the second deck of a carrier is a giant hangar with lots of open area for planes.

Next question?

[Lazar]

And I would add that warp coils might be quite heavy. Memory Alpha says that they're made out of densified minerals.

[Teaos]

And we see a trend in scifi that dence = strong.

[McAvoy]

That is true most things. I still haven't seen any Navy in the world armor their ships with styrofoam... yet.

Aircraft carriers have a large hanger about 800 feet by 100 feet, 25 feet tall. That is large weight saving measure. Imagine if the 96,000 tons of an aircraft carrier was built like a battleship. Wouldn't be as large. Armor takes up very little space but is very heavy. Also those nuclear reactors are much heavier than conventional types.

The closest US design that approached the tonnage of an aircraft carrier was the Tillman Battleships between 1916 to 1920. They were designed as a upper limit for a ship to pass through the Panama Canal, which was at the time a requirement for all navy ships. So dimensions were 975 feet 108 feet and weighed anywhere between 70,000 to 90,000 tons, with anywhere between 12 16" guns to 15 18" guns, with speed between 21 knots to 27 knots, armor as thick betwen 13.5" to 18". They were much smaller than a Nimitz class because there designed as a battleship.

Also part of the Nimitz class design is a deeper hull (taller), which also added weight but had the benefit of many things especially seakeeping.

[stitch626]

And we don't know the actual mass of duranium.

[Tyyr]

Those nacelles look to be nearly solid... something.

[Lazar]

Well the Galaxy class nacelles seem to have a lot of open space.

[Tyyr]

Yes, there's a central opening that's surrounded by meters thick chunks of solid metal. They're probably a tad of the heavy side.

[Captain Seafort]

There's another big point people are missing; aircraft carriers don't weight 100,000 tons - that's their displacement. i.e. the mass of the water occupied by the submerged portion of the ship's hull. What their mass is I've no idea.

Regarding duranium, I suspect it's density is about 19 g/cm^3 (cookie if you can guess why).

[McAvoy]

Well if you feel froggy, steel weighs 40 pounds per square foot, one inch thick. So feel free to start doing some math. I expect the exact weight of the Nimitz class sometime by 2020.

Actually, the actual weight of the ship is not that far off from the displacement of the ship. I have to find it, but I have a figure for the Nimitz class when they launched one of the ships at being around 72,000 tons which is with not everything installed yet.

I also agree that we have no clue how dense or how much duranium or tritanium or whatever warp coils or whatever else the ship uses weighs.

[Bryan Moore]

It's also wholly possible that the matter stores are incredibly dense, as well as the deuterium, etc. Yes I know its just hydrogen, but perhaps its really really really really condensed. Or for that matter, any elements/matter.

[McAvoy]

While that is not a bad idea, it's also not out of the realm of possibility that duranium is three or four times as dense as steel. Built a aircraft carrier out duranium like that then you would rapidly approach Starfleet ships, in mass.

I am leaning on the warp coils being dense. But for all we know it could be the captain's chair that takes up the 99% of the mass.

[Coalition]

There's another big point people are missing; aircraft carriers don't weight 100,000 tons - that's their displacement. i.e. the mass of the water occupied by the submerged portion of the ship's hull. What their mass is I've no idea.

Probably identical. An object placed in water will displace enough water to either equal its mass or volume, whichever comes first. Displacing equal to its mass means the ship floats. Displacing equal to its volume means the ship sank.

Regarding duranium, I suspect it's density is about 19 g/cm^3 (cookie if you can guess why).

Depleted uranium?

It's also wholly possible that the matter stores are incredibly dense, as well as the deuterium, etc. Yes I know its just hydrogen, but perhaps its really really really really condensed. Or for that matter, any elements/matter.

From the TM, deuterium is stored in slush form (aka liquid/solid mix). A GCS carries 62,500 cubic meters of deuterium, which is stored in tanks. Each auxiliary tank has 113 cubic meters of internal volume, and carries 9.3 tons of liquid deuterium. The problem is that this is 82.3 kg/cubic meter, or about half the density of liquid deuterium. So for some reason they keep the tanks half full (safety, prep, boiling off, etc).

82.3 kg/cubic meter times 62,500 cubic meters is ~5,000 kg, or 5 tons of deuterium. Assuming the tanks were full, it would be ~10,000 tons of deuterium.

Now the fun part is asking if storing the deuterium as heavy water would be more efficient (not to mention convenient) to carry. That stuff is 1.106 g/mL. 1000000 mL per cubic meter means 1,106,000 g/cubic meter, or 1.106 tons per cubic meter. Unfortunately, most of this is water. Specifically, 16 protons and neutrons are water, and only 4 are from the deuterium. Very convenient, as it means we can divide the density by 5 to get the amount of deuterium stored per cubic meter.

So .22 tons per cubic meter of deuterium, aka 220 kg per cubic meter, or almost 3 times the density of the slush deuterium being carried in cryogenic tanks.

The fun question is, why isn't this being done? Mass penalties from carrying the excess oxygen perhaps?

[Aaron]

Depleted uranium?

Certainly wouldn't want to be in those ships if the hull got breached.