One trademark of Castle High School's football program the past several years has been mental toughness — the ability to overcome adversity and plow forward despite facing challenges largely out of the Knights' control.

Turns out, this season is no different.

The latest blows to Castle came this past weekend. On Sunday, several Knights learned that their friend and former teammate, Cory Aiwohi, drowned while diving with friends in waters off Ka'a'awa.

Aiwohi, 16, was a slotback on the Knights' JV team last season before transferring to Kailua in the summer. He was not on the roster at Kailua this season.

Aiwohi also had played in the Kane'ohe Knights Pop Warner football program, so many Castle players knew him well even before high school.

"He got lost (at sea) Saturday, and I got the call that night," said Castle junior running back/linebacker Kawehi Sablan, a good friend of Aiwohi's since intermediate school. "It's made me realize how important life is."

Last year, another of Sablan's Castle football teammates, Patrick Kapahu, died in a freak skateboard accident late in the regular season. The Knights played at Kahuku just hours after Kapahu was taken off a life support system.

This time, Castle must play its O'ahu Interscholastic Association first-round playoff game tomorrow against Leilehua.

"It's hard (to focus), I've had a lot of things on my mind," Sablan said after Tuesday's practice. "But I want to play for (Aiwohi)."

Kickoff for tomorrow's game is 7:30 p.m. at Mililani's John Kauinana Stadium. It will be televised live statewide on OC16, but the broadcast site has cost the Knights home-field advantage, despite being the higher seeded team.

"We just gotta deal with what's given to us," Sablan said.

MOANALUA'S ROBINSON COMMITS TO HAWAI'I

Moanalua senior pitcher Sarah Robinson, the OIA Eastern Division's reigning softball Player of the Year, has made a verbal commitment to play for the University of Hawai'i in 2008-09.

Robinson went 10-1 last regular season, with a 0.47 earned run average and 76 strikeouts in 74 innings. Her sister Kate is a senior All-American pitcher/first baseman for the Rainbow Wahine.

OIA, ILH VOLLEYBALL TOURNAMENTS HEAT UP

The girls volleyball season gets ratcheted up a notch tonight on O'ahu with four OIA Red Conference quarterfinal matches, two OIA White semifinals and two Interscholastic League of Honolulu Round 2 tournament semifinals each in Division I and Division II.

In ILH Division I action, Sacred Hearts is at 'Iolani and Kamehameha travels to Punahou. Both matches are set for 6 p.m. In ILH DII, a doubleheader at Hanalani pits Word of Life against University High at 5 p.m. and Hawai'i Baptist vs. Hanalani at 6:30.

In the OIA Red quarterfinals at Mililani, Kahuku plays Kapolei at 6 p.m., followed by Kalani vs. Mililani at 7. At Roosevelt, Radford faces Moanalua at 6 and Kailua meets Roosevelt at 7.

The OIA White semifinals at Kaimuki will pit winners from last night's quarterfinals at 6 and 7.

Read Wes Nakama's blog on prep sports at http://blogs.honoluluadvertiser.com

Reach Wes Nakama at wnakama@honoluluadvertiser.com.