PORTLAND, Maine — A Massachusetts boater accused of causing a collision that killed two people on a Maine lake testified Friday his boat was traveling at just 30 mph at the time of the crash. He also said he drank three beers that day, far fewer than the prosecution says.

Robert LaPointe gave a dramatic account of events leading up to the collision, which he said came out of nowhere, leaving him and his passenger floundering in the water as his powerboat roared ashore and into some woods.

At first, LaPointe thought he hit a raft or a log or a floating dock that had broken loose on the night of Aug. 11, 2007, on Long Lake in Harrison, he testified. It wasn’t until the following day that he saw the remains of a smaller boat he’d run over and learned that two people were missing, he said.

The bodies of Terry Raye Trott, 55, of Harrison, and Suzanne Groetzinger, 44, of Berwick, were recovered three days later. LaPointe, 39, of Medway, Mass., is charged with two counts of manslaughter and aggravated operating under the influence.

LaPointe took the stand in his own defense to rebut key elements of the prosecution’s case: that he drank six or more beers before operating his boat, that he was speeding at 45 mph — possibly faster — on a dark, moonless night, and that he suggested that a nurse substitute her blood for his for a blood alcohol test.

On cross-examination, he maintained that the crash occurred because the other boat didn’t have any navigational lights, not because he was reckless or drunk.

“It’s like going out on a highway [in a car], shutting your lights off and sitting there,” LaPointe said.

The crash spurred discussion on whether steps need to be taken to better protect boaters on lakes and ponds. Critics contend LaPointe’s 32-foot speedboat with twin 435-horsepower engines was too big for a busy lake that’s 12 miles long but just a mile wide.

Closing arguments are scheduled for Monday.

LaPointe said Friday he was careful when he shoved off in his boat shortly before the fatal collision because there was a lot of traffic on the lake.

Later, he said he sped up to 30 mph before being startled by “a violent impact on my boat like we had hit something.” He and his passenger were thrown into the water and swam 1,800 feet to safety while his boat continued across the lake and traveled 100 feet into the woods.

LaPointe testified that he repeatedly told Warden Jason Luce that he’d been operating at 30 mph, but the warden insisted the boat must have been going faster.

At one point, “I looked up and said, ‘maybe 40, maybe 45,”’ LaPointe said Friday, suggesting that he felt pressured into making the statement.

Cumberland County District Attorney Stephanie Anderson played two tapes of LaPointe being interviewed by Luce. On the tapes, LaPointe said he was going 45 mph and that he had drunk a six-pack or more during the day.

But LaPointe told Anderson that the tape contained only portions of his interview with Luce, and that he earlier had told him he was going 30 mph.

LaPointe meticulously recounted everything he had to drink that day, from Gatorade to beer. He handled six beers during the day, he said, but insisted he drank only three.

He took only a sip of a beer he ordered with lunch at a Naples restaurant and opted for a Sprite instead, he said. Late that afternoon, he drank two Bud Lights while with friends at a popular sandbar on the lake, but spilled another before drinking any of it. That night, he grabbed two beers while tied up to a friend’s pontoon boat, but drank only one of them before departing, he testified.

He suggested there could have been a misunderstanding with the nurse who took his blood sample three hours after the crash. She testified he indicated he wanted her to draw her own blood for the sample.

But LaPointe said he merely asked her what she would do in his situation, had she been asked to give a blood sample. His sample later came back with a blood alcohol content of 0.11 percent. The legal limit for operating a boat is 0.08 percent in Maine.

Anderson said the blood alcohol test results are consistent with someone who had been drinking all day, and that LaPointe had told a nurse that that’s what he had been doing.

“Isn’t it true you drank 12 beers that day?” she asked. LaPointe denied the assertion.

The defense says LaPointe was sober and that the fatal collision was a tragic accident. It also contends LaPointe’s blood sample yielded inaccurate results because it stayed in a warden’s vehicle for more than 30 hours before being delivered to a lab.