IMHO they are not equivalent, mainly because the very reason you choose to travel in a ship.
That's one of many reasons why Hovtej's
QE2 cruise is in no way equivalent to interstellar travel in
Traveller. Another reason Pendragonman's reminder that terrestrial ships have weather decks thus essentially "free" life support.
To really compare sea ship travel with Traveller Space travel, we shuld go to a time when the plane was not an option, and the ship was relly used to move people, not only for luxury trips where the goal is the trip itself, not reaching the destination port.
That's not a good equivalent either because we all too often ignore the
relative cost of interstellar passage in
Traveller versus the cost of oceanic passage in history. The late 1800s/early 1900s emigrant trade is a good way to examine our many faulty assumptions regarding cost.
In discussions of this type, the emigrant trade across the North Atlantic is always brought up and this thread is no exception. The peculiarities of that trade are rarely mentioned, however. First, that trade lasted only a few decades.
Second, that trade relied heavily on government subsidies of many kinds. Not only were ship construction and operation subsidized to great degree, but emigrants were encouraged to leave their native countries with deliberately cheap transport and lodging costs while also encouraged by destination nations via land grants, lax immigration controls, and other methods.
The emigrant trade relied on several political, social, and economic conditions which were definitely abnormal. That means the emigrant trade was an exception and not a rule, and definitely not something we want to use as an analogy for everyday interstellar travel in the
OTU.
So, seeing as governments will rarely subsidize your trip, how does it cost to travel in
Traveller? The Usual Suspects can now begin "debating" the credit to US dollar exchange rate while dutifully ignoring the metagame reason such exchange was created. While they're bleating and honking at each other, the rest of us can use the
Big Mac Rule from
The Economist to get rough handle on how much a passage will cost the average inhabitant of the
OTU.
What's the
Big Mac Rule? It's the amount of time you'll need to work to earn the purchase price of a Big Mac hamburger wherever you happen to live. Thoughtful readers will quickly realize that any number of economic variables are "folded" into that seemingly simple question; differing average wages, differing costs of living, exchange rates, taxes, logistics, etc. The heart of the rule relies on there being the same (allegedly) item for sale by the same company across a huge number of locations. This allows us to get a rough, but workable, grasp of relative purchasing power across a huge number of locations.
Substituting a starship ticket for a Big Mac, what sort of income does our average inhabitant of the
OTU have with which to purchase their interstellar passage? Enter
LBB:3 which gives us four levels of long subsistence; Struggling, Subsistence, Ordinary, and High. If you want ordinary food and lodging for a year, you'll need to earn
4800 credits. If you want to live high on the hog, you'll need to earn
10,800 credits.
Now, compare and contrast those two income levels with starship passage costs:
- Ordinary living: 4,800 Cr per year
- High living: 10,800 Cr per year
- Middle passage: 8,000 Cr
- High Passage: 10,000 Cr
What does the
Big Mac Rule tell us about traveling in
Traveller? How many ordinary types can afford almost
two years living costs for a single Middle passage? Would a 57th Century Hovtej have been aboard that 57th Century
QE2 if it cost him nearly
three years of ordinary food and lodging?
We can't use the current day luxury cruise liner business to understand interstellar travel in the
OTU. We can't use the late 1800s/early 1900s
Blue Ribbon era in the North Atlantic either. The best historical analogy I can dredge up would be travel between UK/India and Holland/Indonesia during the 1700s heyday of the nationally chartered, joint stock, merchant, companies.
You only traveled between Europe and India/Indonesia because your employer or government sent you. You traveled for specific purposes. You traveled knowing you'd be gone for years if not decades.
You didn't travel on a whim. You didn't travel because you wanted to see the sights. You didn't travel for pleasure. Traveling was very expensive and traveling took time, so you made very sure you were traveling for very good reasons.
CT'77 described interstellar travel as rare and the passage rates reflected that.
CT'81 described interstellar travel akin to intercontinental air travel but
didn't change passage rates to reflect that.
If you want interstellar travel to be akin to flying between continents, you either need to drop passage costs or raise wages.