Knokke-Heist, Belgium — The sea at this seaside resort was uncharacteristically calm. So is the mood between the United States and Western Europe over trade, according to Wilhelm Haferkamp, the European Community's external relations commissioner. ''I do not see any danger of a trade war ahead of us, not in the near future or in the medium term,'' he said.
US Deputy Agriculture Secretary Richard E. Lyng joked: ''I'm glad my friend from the Community thinks that. But I'm sorry he really believes it.''
So much of transatlantic trade relations these days tends to be threats and intimidation that it is often difficult to see the facts.
Yet the real news is this: The sea may not be calm, but the ships continue to run, and to run well.
''Our trade conflicts are minor,'' Mr. Haferkamp told a two-day conference on US-European relations here last week. They affect no more than 5 percent of the the conflicts are settled even before they materialize.''
Difficulties do exist, of course - and several loom menacingly on the horizon.
Etienne Davignon, the Community's industrial affairs commissioner, told the conference the US and the EC could be heading for a ''major battle'' over trade in high-technology products that ''could make the current dispute over agricultural trade look like chicken feed.''
He and other Europeans are worried by the Reagan administration's threats about putting strict limits on exports of high-tech equipment to East-bloc nations for security reasons and to extend them to some West European countries, if they don't cooperate.
Mr. Davignon said the administration's paranoia over the Soviet Union and its allies using Western technology to expand their military might could affect future cooperation ventures between US and West European companies and even undermine the psychological foundations of the Western alliance.
Meanwhile, the dispute between the US and the EC over trade in farm products continues to simmer. The US argues that high EC spending on agriculture (about two-thirds of the Community's annual budget), including price supports and export subsidies, encourages production to such an extent that huge surpluses build up and need to be dumped on world markets - some of them traditionally held by US exporters.
''The Community's agricultural policy has succeeded to the point of disaster, '' Mr. Lyng said, adding that the EC spent $5.4 billion on agricultural export subsidies last year. The US helped pay for that ''success,'' he said, in the form of sales lost to subsidized competition, restricted access to the EC market , and the downward effect EC overproduction and subsidized exports had on prices.
But in dozens of meetings over the past three years, including a key meeting in Geneva last week, US and Community representatives have narrowed their differences on the farm-trade question. Some analysts now say the crisis period may have passed.
''I think that in the recent past we have come to, or at least are approaching, an understanding that was not there three years ago, or even six months ago,'' Mr. Lyng told the conference. Both sides, indeed, have recognized that too much is at stake to risk seriously damaging the trade relationship with retaliation and counterretaliation.
The 10 nations of the EC collectively remain America's most important trading partner, well above Japan and Canada. They take about one-third of total US exports every year, while West European firms sell some $80 billion worth of goods and services on the US market - about one-quarter of their total annual exports.
Mr. Haferkamp, emphasizing that administrations on both sides of the Atlantic continue to be ''basically (for) free trade whatever the protectionist pressures to which they have been exposed,'' paid special tribute to the present US administration for the ''determination with which it has resisted protectionist pressure'' from industry.
US Deputy Secretary of Commerce Olin Wethington projected, ''We will not see a significant protectionist shift'' in the US this year despite strong industry pressure on a president running for reelection.
Many experts, in fact, forecast expanded trade between the US and the EC in coming months and years.
The economic upturn in the US, coupled with the continuing strength of the American dollar, which makes European goods relatively inexpensisve to US buyers , will mean increased sales on the US market of European chemicals, machinery, aircraft, and related equipment and farm products.
For US companies, strong sales of products ranging from business equipment and aircraft to telecommunications equipment, consumer goods, electronic components, and agricultural products could be in the offing if the expected economic upswing materializes in Europe.
Efforts to improve the US-EC trading relationship, and even to use it as a model for strengthening the world trading system, continue. Earlier this month, US trade representative William Brock invited key ministers from 23 countries, including the EC nations, to meet in Washington on May 10 and 11 to begin exploring ways to further liberalize the international trading system.