enlarge John Patriquin/Staff Photographer

Principal Derek Pierce starts Thursday’s meeting of Casco Bay High School faculty, students and parents at the Portland Arts and Technology High School. The expeditionary-learning school had the city’s lowest per pupil cost last year.

enlarge John Patriquin/Staff Photographer

Will Nelligan, a junior this year, attends a meeting Thursday to discuss this fall’s curriculum at Casco Bay High School in Portland. “This school is so much more than learning out of a textbook,” he said, noting that his standardized test scores validate his education.

It was a perfect beach day, but in the classrooms at Casco Bay High School a dozen or so students, their parents and teachers were hard at work.

The students were there to comment on plans their teachers had drawn up for what they'd be learning in the new school year, still three weeks away.

The energy level appeared high as plans were unveiled for a study of blood, including a blood drive and visits to hospitals and a blood research lab.

Then there was talk of French and Spanish classes that would focus on colonialism, religion and faith -- with a possible trip to Quebec.

"These are our sports tryouts," said Principal Derek Pierce, to claps and cheers.

Entering its third year, Casco Bay High School, which has no sports program of its own, has won rave reviews from many of the students who have chosen it over the city's two other high schools.

The school was the inspiration of Superintendent Mary Jo O'Connor, who sought a $600,000 grant from the Bill and Melinda Gates Foundation. The foundation had given Outward Bound USA money to open 20 new schools based on expeditionary learning, which teaches through hands-on projects and real life, out-of-classroom experiences.

Expeditionary learning has been practiced at Portland's King Middle School for more than a decade. The approach has been credited with boosting achievement scores in a school population that includes some of the largest percentages of low- income and non-English-speaking students in the city.

But for all its energy and positive reviews, Casco Bay High School has also been criticized for siphoning off resources from the city's two other high schools, Portland and Deering. Now, with controversy swirling around a $2.5 million budget deficit that has prompted calls for O'Connor's dismissal, the city's youngest high school has come under new scrutiny by critics who say it is a luxury the city cannot afford.

Even before the school opened, skeptics questioned the financing of the new school and its impact on what some consider a bloated school budget. At the time, Kathleen Casasa, the president of the teacher's union, said opening a new school amid declining enrollments made no sense. She warned the school would create political tensions between the School Committee and City Council, hurt teacher morale and erode community support for current programs.

But the School Committee gave it the go-ahead, with only the committee's two fiscal conservatives voting in opposition.

Portland's previous great experiment in high school education fell flat on its face. In the 1980s, Portland High took part in a nationwide movement to create schools-within-a-school. Students in the programs had different schedules and teachers were free from such duties as monitoring bathrooms and study halls. It was a prescription for resentment and divisiveness among regular faculty members, and the program was shut down three years later.

Today, students heading to high school are able to choose which of the city's three schools to attend. Each has a distinct personality. With 230 students in grades nine, 10 and 11, Casco Bay is housed in the upstairs rooms of the Portland Arts and Technical High School. Students are grouped heterogeneously, unlike the other two schools, which divide students into college preparation, honors or general education programs.

Some 35 percent of Casco Bay's students are from low-income homes and 9 percent are from non-English-speaking backgrounds. Many come from King Middle School, a feeder school for Portland High, and are familiar with expeditionary learning.

Portland High opened in 1821 and is considered the city's urban high school, with a lofty past that includes a roster of illustrious alumni such as movie director John Ford, arctic explorer Adm. Robert Edwin Peary and architect John Calvin Stevens.

Close to 50 percent of its roughly 1,060 students come from...