Jurors in the Scott Peterson (search) murder trial inspected the defendant's small aluminum fishing boat, then heard an expert testify that a lifeless body could have been thrown overboard.

The testimony Tuesday was intended by prosecutors to counter claims by the defense that Peterson could not have heaved the 153-pound body of his eight-month-pregnant wife, Laci, into San Francisco Bay without the boat tipping over. Peterson bought the boat just weeks before Laci Peterson (search) went missing Dec. 24, 2002.

David Weber, vice president of engineering for Missouri-based Lowe Boats, told prosecutor Dave Harris that it had not been "my experience" that the boat capsized easily.

On cross-examination, however, Peterson lawyer Mark Geragos (search) pointed out all buoyancy tests were performed while the boat was partially full of water, making it more stable.

Weber also acknowledged side stability tests were performed by placing 145 pounds evenly along the boat's inner side, not concentrating the weight in a way that might make it more likely to tip.

"You ever try to put 400 pounds in one area?" Geragos asked in an apparent reference to the combined weight of the Petersons. Prosecutors allege Laci Peterson's body was weighted with as much as 40 pounds of concrete to ensure it sank.

"No we haven't," Weber said.

Weber also said no tests were performed in choppy conditions similar to those on San Francisco Bay the day Laci Peterson disappeared.

"And you haven't done any of these tests in saltwater?" Geragos asked.

"No," Webber said.

The prosecutor pointed out salt water is more buoyant than fresh water, making it less likely for the boat to capsize.

Prosecutors allege Peterson killed his wife in their Modesto home, drove to the bay with the body in a tool box, ferried it onto the open water and dumped it.

The remains of Laci Peterson and the couple's fetus washed ashore about two miles from the marina where Peterson set off on what he claims was a solo fishing trip.

Peterson, 31, could face the death penalty or life without parole if convicted.

Court will not be in session Wednesday while Geragos attends a hearing in an unrelated case. Jurors also will not be present Thursday when Geragos argues for a dismissal of charges or a mistrial based on allegations that a detective lied on the stand.