IN THIS BUSINESS you're prepared to believe almost anything. But even the most elastic credulity finds its limits upon learning of the recent energy-saving proposal of a number of prominent naval architects and engineers that cargo vessels of the future be propelled by "sail." Not enough that a bunch of California visionaries are suggesting that human beings could actually survive in houses equipped with neither furnaces nor central air conditioning. Now here comes a pack of wild sea dogs claiming that by 1984 (woeful date) New York harbor could be teeming with long, pointy ships festooned with odd, triangular sheets.

The idea (if you're generous enough to call it that) is that the wind will be blowing on the sea when these new miracle ships hit the water, and that the wind will fill up the sheets - are you following this? - will fill up the sheets, and thus . . . move the vessels. For such as this the U.S. Maritime Administration has given a group of architects, including a professor at the Massachusetts Institute of Technology, the sum of $108,000 for a feasibility study. Good luck to them. Even if such a preposterous scheme did work, who in his right mind would wish to see some flouncy floating nightgown replace our roaring, smoking sleek steel beauties?

It's not that we wish to appear reactionary or hostile to progress. But is this really progress? Should we give up our cars for horses just because horses are proved faster? Should we forfeit our lamps for candles, just because candles last longer and are easy to make? What of the telephone? Should that go too because letter-writing is more accurate? Of course not.

There is a world of grace and beauty to consider, as well as the world of cold efficiency. If our technological masterminds do not learn this soon, we shall sail straight to hell.