Chase Manhattan Corp. and the Chesapeake Savings and Loan Association formally announced yesterday that the giant New York bank company has made a $3.8 million bid to acquire the Annapolis-based thrift, the first step in Chase's plan to buy three Maryland savings and loans.

In a statement that was jointly released in New York and Annapolis, Chase announced that it has agreements with holders of more than 50 percent of the midsize thrift's 100,000 shares of stock, at $35.42 per share. The transaction will become final, said Chase, once it has agreements with two-thirds of the association's 180 shareholders and once it has received all necessary governmental and regulatory approval.

The major hurdle for Chase will be getting the General Assembly to enact legislation giving it authority to convert to commercial bank branches Chesapeake and the two other associations it plans to acquire. That legislation, which the assembly is expected to take up during a special session as early as next month, would give Chase interstate banking authority in Maryland nearly a year ahead of a schedule approved by the legislature last winter prior to the state's savings and loan crisis.

A statesman for Chase would not comment on what progress the nation's third largest bank is making in taking over two other thrifts, Merritt Commercial Savings and Loan of Baltimore and Friendship Savings and Loan of Bethesda. Chase officials acknowledged last month that they had made offers for all three associations.

The key to that package, from the standpoint of state officials, is the acquisition of Merritt, which voluntarily went into conservatorship in May when the thrift crisis hit. Merritt represents a potential financial problem to the state second in size only to the troubled Old Court Savings and Loan Association, which was forced into conservatorship amid allegations of improprieties by its owners and directors.

Benjamin Bialek, a legislative aide to Gov. Harry Hughes, called the Chase-Chesapeake announcement "good news" for state officials who are still trying to nurse back to health some of Maryland's largest thrift associations. All savings and loans with more than $40 million in assets must have federal insurance by the end of this year or ultimately face liquidation, according to emergency legislation enacted in May.

Though Chesapeake officers thought they could raise enough funds to meet a key requirement for federal insurance, they chose to accept Chase's lucrative offer instead. Chesapeake's stockholders will get almost four times what they paid for their stock when the association converted from a mutual savings and loan in 1983.

"It's a fair transaction as far as the shareholders are concerned," said Chesapeake president Arthur Silber.

If the legislature agrees to allow Chase into Maryland, the New York bank with $86.3 billion in assets will get the jump on one of its rivals, Citicorp. Under legislation enacted this year by the assembly, Citicorp will begin branch banking in Maryland next summer after investing $25 million and creating 1,000 jobs. Other out-of-state banks meeting the same investment and job criteria can establish operations in Maryland at the same time.