A port no longer waiting for the ships to come in

''We're the new kid on the block,'' C. W. (Bill) Herbert, executive director of the Greater Baton Rouge Port Commission, is wont to say.

What he means is that the port, one of the top five in the country in terms of tonnage handled, is only 26 years old.

Baton Rouge is at a deep place in the river, and has had plenty of land to build on, unlike many other harbor cities. Today this ''young'' port is trying to capitalize on its position as the country's farthest inland deepwater port to become a major world trading post. Officials here believe it is well positioned to tap into what is expected to be the ''great coal rush'' of the next few decades.

But just 30 years ago there were no public port facilities here at all. So local officials went to the Louisiana Legislature for authorization to float bonds, and then the first facilities were built here, on the west bank of the river, across from the city of Baton Rouge.

But as Mr. Herbert, formerly in the foreign trade department of the Missouri Pacific Railroad in New Orleans, found out, it's hard to start a port from scratch.

''People considering sending ships in would say, 'How many ships did you handle last month?' and we'd have to say, 'Well, uh, none.' And they'd say, 'Then how can we be sure you know what you're doing?'

''Then finally I ran into a guy at a party, a Yugoslav, and he said, 'Bill, I'm gonna take a chance on you.' ''

Mr. Herbert has the date of the first ship's arrival tattooed in his memory: June 7, 1956. After that, the Baton Rouge port began to build a record. ''And so when people would ask how many ships we handled last month, we'd be able to say, 'Eight,' for example, and they'd say, 'Oh, really?' ''

It's been up from there, although Baton Rouge has recently had to yield pride of fourth place (behind New Orleans, New York, and Houston) to the Alaskan oil port of Valdez. But this No. 2 port in Louisiana shipped 80 million tons last year and is prospering, despite recession.

River traffic is down, and marine service industries are hurting, but port revenues through August were up 7.5 percent over the same period last year.

''And that's not counting $1 million in midstream business,'' Mr. Herbert says. This is the transferring of coal, grain, or other bulk cargo from ships to barges in ''midstream'' rather than at a pier, then shuttling them to port. This cuts down on congestion at portside.

General economic conditions have stilled debate somewhat on two long-term questions facing the port: expansion of coal facilities and deepening the river channel.

Three planned coal terminals have been put on hold. General recession, depressed oil prices, and Poland's recent dumping of coal on the world market have ended what one official calls the ''Klondike gold rush'' of coal exports the country had been experiencing until then.

But Herbert Haar, assistant director of the New Orleans Port, expresses optimism that at least two of these terminals will be built eventually.

Mr. Haar and his boss, Ned Reed, director of the New Orleans Port, explain how the coal fizzle may be more apparent than real. The European market may have lost its oomph, but steam coal continues to go to power plants in Florida. And a lot of coal traffic is being handled ''in midstream,'' without construction of new facilities.

Considerable expansion of existing facilities is planned or under way downriver from Baton Rouge, too.

A governor's task force is to hear Jan. 1 from a New York firm it has commissioned to study the potential effects of deepening the channel, now maintained at 40 feet to 55 feet. Mr. Reed says, ''The economics would probably be there for coal and grain, but the question would be, how far to go?'' Which is to say, the channel might not be deepened all the way to Baton Rouge. No major US port now has a 55-foot channel, though, and it would be a boon for Baton Rouge to be included in the deeper channel.

As it is, its inland position gives it an advantage over many other US ports for shipping coal to distant places. Because the port is on the Mississippi River, raw material suppliers can ship goods here more easily than to some other US ports. At the same time, Baton Rouge is close enough to the Gulf of Mexico to make it a global trading post.

However far upriver a 55-foot channel would be maintained, who pays for the dredging remains a question. Dredging will not be necessary the entire length of the river, only around several shallow-water bends. Still, it's ''massively expensive,'' Mr. Reed said - and Uncle Sam may no longer be willing to pay for it.

The Reagan administration favors relying on local ''user fees'' from shipowners to pay for dredging. But Mr. Reed suggests shipowners aren't the only ones that would benefit from dredging, and that some other cost-sharing arrangement might be more appropriate.