Fair Lanes Inc., a Baltimore bowling alley chain, disclosed yesterday it has acquired 5.1 percent of Brunswick Corp. and apparently is trying to use the shares to pressure Brunswick into selling its 250 bowling centers to Fair Lanes.

Fair Lanes runs 89 bowling centers, mostly in the East. Based in Skokie, Ill., Brunswick Corp. manufactures boats and sporting goods and operates 250 bowling alleys across the country.

"We're considering the desirability of seeking to exchange the Brunswick shares for bowling center assets of Brunswick," Fair Lanes' chairman Sidney Friedberg said yesterday.

Friedberg said his company also is considering joining other companies in a possible attempt to acquire other assets of Brunswick.

Brunswick chairman Jack F. Reichert said Brunswick is not interested in trading its bowling center operations for the stock bought by Fair Lanes.

Brunswick officials said they consider Fair Lanes' move "unsolicited," but not necessarily hostile. But a company spokesman said it would be wrong to rule out the possibility that Brunswick might eventually sell its bowling operations.

Officials from Fair Lanes and Brunswick met on Aug. 4 to discuss Fair Lanes' stock purchases. At that time Brunswick officials told Fair Lanes they were not interested in pursuing negotiations.

Fair Lanes' Friedberg said the company's board has authorized the purchase of up to 10 percent of Brunswick's stock. Brunswick shares closed yesterday at 20 1/4, up 1/8, with 56,900 shares traded on the New York Stock Exchange.

Fair Lanes has spent $11.5 million, including brokerage fees, for the 594,200 shares of Brunswick stock it now owns. Friedberg said the company has borrowed money to buy the stock and has arranged financing to purchase additional shares.

Securities analysts have estimated Brunswick's bowling operations, its Recreation Centers Division, to be worth between $60 million and $100 million. The Recreation Centers Division had sales last year of $112 million and a $9.2 million operating profit. Brunswick Corp. as a whole had sales of $1.1 billion last year and profits of $78.2 million.

Brunswick successfully fought off a takeover attempt earlier this year by Whittaker Corp. of Los Angeles by selling off its medical division to American Home Products, a company spokesman said yesterday.