D.C. Fire Chief Theodore R. Coleman yesterday rejected the fireboat commander's recommendation that the department acquire scuba gear, but he said he may start requiring members of the fireboat staff to complete swimming courses.

Coleman also dismissed as "speculative and irresponsible" the allegation by fireboat Capt. H. Linden Cohee that at least two deaths could have been prevented last year if the department had had proper diving equipment.

Cohee made the statement in a memo to Coleman last Dec. 18, just three days after a man died after his car plunged into the water off Hains Point. With scuba gear, "we would in all likelihood have saved a life," Cohee wrote.

Cohee also said in the memo that with proper diving gear, his staff might have been able to save Kevin Welch, a D.C. police officer who drowned Aug. 4, 1986, in an attempt to rescue a woman from the Anacostia River. A fireboat arrived with divers but without scuba equipment.

Cohee asked Coleman for scuba gear in the memo, which was obtained by The Washington Post. Cohee also asked, in memos written three years ago, for the department to provide the fireboat staff with training in water rescue, survival, lifesaving and "remedial swimming."

Until yesterday, Coleman had not responded to news reports about Cohee's request for scuba gear and training programs for the fireboats.

He said that recent news reports about Cohee's recommendations indicate that "certain factions in the Fire Department are committed in their attempt to erode the public's confidence in the leadership of the agency and their management ability."

Coleman said he did not remember seeing the memos, but that the department does not need scuba gear for underwater rescues because the police department's harbor division "have provided adequate protection."

"I'm not going to get any scuba gear until it's determined that the waterfront police department cannot provide protection," Coleman said.

A D.C. police patrol boat and fireboat lacked diving equipment when they reached the scene of the Aug. 21 crash of a helicopter into the Washington Channel. Both boats arrived within three minutes of the accident, but the fireboat had to wait while the police boat returned to its base to pick up scuba gear.

The pilot escaped from the aircraft, but three passengers were trapped underwater in the overturned aircraft for at least 20 minutes before being pulled to the surface by police divers. The three died later of injuries and "submersion," officials said.

Cohee said in recent interviews that no qualified divers were aboard the fireboat but that a better-equipped fireboat could have provided scuba gear to the police divers.

Tom Tippett, president of the International Association of Fire Fighters, Local 36, said the union plans to ask Congress to order the department to buy diving equipment and expects "a sympathetic response" because of the relatively small price tag, estimated at less than $10,000.

Coleman also said yesterday that he did not know why the department has never required its employes to pass swimming courses. Local agencies that require swimming ability include the D.C. police, the U.S. Coast Guard, the Virginia and Maryland state police, and the police and fire departments of National and Dulles International airports.

Cohee said that at least two fireboat members cannot swim.

Coleman said he has not decided whether to institute a swimming requirement. He also said that fireboat members could have attended any of the three water safety courses offered this year by the police.

Cohee said the courses were open to firefighters who would attend "on our own time, at our own expense."

Coleman accused Cohee and the firefighters union of "ulterior motives" in speaking to the news media about Cohee's requests for scuba gear and training. Coleman said Cohee has complained about being denied a promotion and that the union is involved in contract negotiations.

Cohee said he submitted his memos "long before" the promotion issue arose.

Tippett said, "Our 'ulterior motive' is to see the citizens and visitors to the nation's capital provided with the best fire and rescue protections available . . . . It's strictly a safety issue."