After more debates than decisions, a presidential advisory panel studying maritime regulatory law will get down to serious business when it meets again next month.

That's when the 17-member Advisory Commission on Conferences in Ocean Shipping will have the draft of its report's critical chapter - encompassing findings and recommendations - on the table.During two days of meetings last week, the industry and congressional group made little progress on three crucial issues: the continuation of ocean freight rate filing, the future of antitrust immunity for carrier rate-setting groups and possible alterations to shipper-carrier rate discount agreements, known as service contracts.

In many cases members immersed themselves in semantic debates about ''actual" and "potential" harm under the 1984 Shipping Act and congressional intent under that regulatory law.

They avoided a public bloodletting on the controversial service contracting issue by agreeing to submit written comments that the staff will sort through in a search for consensus.

Facing an April 10 deadline for getting the final report to the president and Congress, Jeffrey N. Shane, advisory commission vice chairman, huddled with advisory commission staffers and devised a schedule designed to kick- start the panel into action.

The staff will draft a findings and conclusions chapter by the end of January. Members will comment in writing by Feb. 5. The staff then will prepare another version of the chapter, which will be the focus of debate during public meetings on Feb. 12 and 13.

"We hope we will then have close to the final version of the (final) chapter," said Mr. Shane, who is also assistant secretary of transportation for policy and international affairs.

The rest of the report will be conformed to the conclusions reached in the final chapter, he said.

Describing last week's meeting, Mr. Shane said it was "a very interesting two days, with robust discussions." Earlier, he jokingly had noted, "For some of us this has been the week from hell."

In a related development last week, the National Industrial Transportation League lauded the Federal Maritime Commission chairman's nine-point list of potential administrative changes to the 1984 act. The chairman, Christopher Koch, outlined in his list possible internal actions by the commission, most concerning contracting procedures.

But James E. Bartley, league president, said administrative action is not the "complete solution the U.S. shippers are seeking."