When twilight falls on the creeks and rivers of hesapeake Bay, and the anchor's in the water and the gin is in the glass, then comes ship-to-shore time -- boat-owners' happy hour on VHF channels 25 and 26. Over the airwaves via TR marine operators in Cambridge and Baltimore crackle the voices of weekend captains reaching out to touch shorebound wives and lovers, family and friends.

It's an eavesdropper's grab-bag of instant sociology: rites of courtship, states of marriage and the family, cultural and economic one-up-manship and the boozy euphoria of Americans at play. Like the party lines of bygone small- town America, the marine channels tell it all:

"Baltimore Marine, Baltimore Marine, this is the Wind Witch, Whisky-Oscar-Zulu five-niner-seven-two. Come back."

"This is Baltimore Marine. Come in, Captain."

"Baltimore Marine, I want to make a collect call. And tell 'em the love boat's calling."(Much background laughter.)

According to the Boat Owners Association of the United States, nearly one out of five American families owns a boat of some type. Those on the Bay, while hardly the rowboat-and-canoe set, nonetheless span divisions of age, race and income, as well as sex, class and culture. Crabbers from Crisfield and New York yacht-owners vie for the same phone channels, usually for the same reasons. Often, theyre just feeling good. But a variation is the eat-your-heart-out call:

(Phone rings) "Hello?"

"Hey, Lorraine! Is that you?"

"Yes. Who's this?"

"This is Bill. We're down here on the boat in the middle of the Chesapeake Bay. We're having a drink and watching a glorious sunset and we just thought you ought to be down here with us."

"Oh, that must be wonderful. Is the weather nice?"

"Couldn't be better. Marge just grilled us a delicious steak and everything is copacetic. Why don't you all come down and join us for a few days?"

"Honestly, you all lead the most glamorous life. But we can't go anywhere, Bill. Fred's not working, you know. He's been laid off."

"Hell, that's a shame. Well, if you change your mind, you just let us know. We've decided it's so nice down here we're just going to cruise around the Bay. All summer."

Eat-your-heart-out calls can also be made to the office, but that's risky. Employees' resentment is usually palpable. The boss can cruise around on workdays if he wants, but workers don't have to like it. An assortment of back-to- the-office calls from the bay overheard this summer indicate that the cheerfulness of employee voices appears to vary directly with a previous history of sharing the boss' boat themselves.

(Phone rings)"Hello?"

"Hey, Ben, it's me. How's the Carson deal?"

"Nothing yet. How's the fishing?"

"Not bad. We got about l3 yesterday. Would've got more but the beer cans kept getting in the way. Any messages?"

"Fallon called again. That's all. Save some of 'em for me out there, hear?"

"Gotcha covered. We'll pick you up at the bridge on Saturday."

Eavesdropping on the marine channels becomes something of an art form after a while. There are connoisseurs of various aspects of the subject. Some, for example, savor the names of the vessels and the verve with which summer captains sound them out. Others concentrate on the aplomb with which the operators channel and deflect the tongue-twisting traffic while ever obedient to nautical custom: Even the most babbling drunk or incompetent, incoherent boat driver is always "captain." One memorable night last month yielded the following exchange:

"Baltimore Marine?"

"Vessel Calling. Come in, Captain."

"Baltimore Marine. This is Ubiquitous."

"Say what, captain?"

"Ubiquitous. Spelling Under-Baker-Ice-Quiet-Under- Ice-Tiptop-Over-Under-Sam."

"Is that the name of your vessel, Captain?"

(Another voice)"Baltimore Marine, this is Clark's Ark."

"Hold on, Clark's Ark, you're on standby. Come in Ubik .. ." (Third voice) "Baltimore Marine?"

"Vessel calling, stand by. Did you get that Clark's Ark?"

"Roger, operator. Clark's Ark Tommy-Zulu-Oscar three- three-four-four . . .

"Then stand by, Clark's Ark. Baltimore Marine calling the Ubik . . . Ubik . . . Ubikituss."

"Ubiquitous."

"Captain, what are your call letters?"

"Uh . . . I don't know, operator. This is a rented boat. Wait a minute, let me look."

"Stand by, then, Ubiquitous. Baltimore Marine calling Clark's Ark."

(fourth voice) "Baltimore Marine, this is Lotsa Junk."

"Stand by, Lotsa Junk. Baltimore Marine to Clark's Ark."

"This is Ubiquitous. I found the call letters. Oscar- Oscar-Sam five-four-one-three."

(Fifth voice) "This is the Water Bed . . . "

On nights like these, it's a wonder any calls get through, not to mention any information. But weighty matters are discussed via ship-to-shore. David Breasted, an official with Boat-US, remembers learning that Richard Nixon had resigned while eavesdropping on a vacationing broker's radio call to his office. The broker's first reaction to the news, Breasted remembers, was, "What'd the market do?"

Echoes of government, however, are less often heard ship-to-shore than those of love and life.

(Phone rings, woman's voice) "Hello?"

(Man's voice) "How's your head?"

"Rotten. Who is this?"

"Don't you know?"

"Omigod. It's you."

"Have a good time last night?"

"I never should have. How'd you hear about that?"

"I been reading about you in the Evening Capital."

"God. I wouldn't be surprised."

"You recovered yet?"

"I'm better. Jeez, if I could only remember . . . "

"Whatcha doin tonight?"

"Oh, just got the kid's to bed . . . Too hot to do anything."

"Me and the boys out here in the boat got us a few six packs cold. Whyncha come on out and feel the breeze. Nice out here on the water."

"I don't know . . . "

"C'mon. Dooyou good. Hair of the dog."

"Forget the hair. Hell, forget the dog."

"C'mon. We can tool over to the dock and pick you up. Your sister can keep an eye on the kids."

"She's in Baltimore . . ."

"Oh."

" . . . But there's Margie."

"Now you're talking."

"I don't know, though. I really shouldn't."

"C'mon. We can pick you up in a few minutes."

(Sigh) "Ohhhh, you guys!"

One night a few years ago, Channel 25 treated nautical eavesdroppers to a semi-proposal. A very self-conscious male voice placed a call to a woman who apparently was on a duty visit to her family in a distant city. The strain of the separation was clearly audible.

He: "We 're anchored here in Harness Creek. No trouble with the boat. (Pause) Wish you were here."

She: "Oh, God, me too! Ooohhh. You just don't know!"

He: "How are things there."

She: "Oh, fine, I guess. But it's sure not the same."

He: "Tell me about it." (pause) "Listen, will you agree to the movers?"

She: "What?"

He: "Will you agree to the movers?"

She: "You mean it?"

He: "Right here in front of all these people."

She: "Absolutely! Oh, ab-so-lutely!"

Sometimes, however, love goes awry, even on Channel 25. Last July 4 the following static cracked over the Bay about 9 p.m.

(Phone rings) She: "Hello?"

He: "Hey, honey. I won't be home tonight. I'm gonna spend the night here on the boat."

She: "You're gonna what?"

He:"Spend the night on the boat."

She: "Well, that's just terrific! Why didn't you tell me before? I could have gone to work tonight."

He: "Well, we were gonna come in, but it just seemed simpler to anchor out here."

She: "Who're you with, anyway?"

He: "Just one of the guys from the marina."

She: "Well, happy Fourth of July!"

Another call was happier:

He: "Whatcha do all day. Just lie around?"

She: "I did some cleanin'. Then some washin'."

He: "All that energy going to waste!"

She: "Well, (giggle) you went fishin'!"

The bulk of weekend boat calls, however, seems to come from boating parents to children left ashore -- often sullen, monosyllabic teenagers either excluded or self-excluded from the weekend on the bay.

(Phone rings) "Hullo."

"Hi baby! It's Mom!"

"Oh."

"We're calling from the boat and it's beautiful out here! I wish you were with us!"

"Uh huh."

"Everything okay?"

"Uh huh."

"Where's Cassie?"

"I don't know where she is. Ask me if I care."

"Now, baby, please don't fight with your sister."

"Listen, mom, you know what your little precious did? She made this big deal about what she wanted for dinner and I cooked these hamburgers and peas and everything and then she said she couldn't eat and went out to play kick-the-can. You said I was supposed to be in charge and she won't do anything I say . . . "

The number of such calls is almost painful to hear: the parents sounding guilty and over-exuberant, the children alienated and resentful. It is rarely clear whether the kids have been left behind or refused to go, but often it sounds like the latter. Divorced fathers call their children from boats, often heartily inviting them aboard. The children remain polite and even warm, but wary.

"Hiya son. How's the guitar?"

"Huh?"

"I said how's the guitar?"

"Oh, Dad. Hey, it's great Dad. I just haven't had a chance to play it much. But it's a really great guitar. I really appreciate it."

"Well, I hope you enjoy it. Feel like any sailing this weekend? We could pick you up in Annapolis."

"Gee, Dad. That sounds great. But I told Barry I'd go with him to the mall tomorrow. I sort of feel like I have to go . . . "

According to Channel 25, however, the American family is not all lost. One weekend last month brought this call:

(Phone rings) "Hello?"

"Hiya kitten!"

"Hey! Dad! You calling from the boat? Wow, neat!"

"Just thought we'd see if you need anything. Everything all right?"

"Great, Dad! Jennie's over at Sarah's and Bobby's got a very heavy date and I don't know where Tommy is. He's around here somewhere. How are you guys? Getting good sailing?"

"Well, the wind is kinda light. We had to motor most of the way."

"Motoring! Poor Dad! Well, I hope you got the blender going anyway. Hate to think of you guys suffering in the heat."

"We're fine. Your mother fixed a terrific dinner. Corn on the cob and everything."

"Good. Well, don't worry about us. We're okay. Have fun."

"Okay Kitten. Be good."

"Bye, dad. So long. Love ya! Over and out!"