A vessel aground in Kane­ohe Bay has already done considerable damage to a portion of the barrier reef about a half-mile from shore, according to officials with the conservation group the Nature Conservancy.

"It’s some of the nicer coral in the bay," said Jason Durnin, the group’s project manager in Kaneohe. "There’s a lot of damage already. Probably over 100 coral heads have been smashed. … There’s one area that’s just turned to rubble."

Durnin and other members of the conservancy, who are working to preserve live coral from algae damage, passed by the area where the vessel was aground Thursday afternoon.

State officials said the reef area is used to conduct marine tours.

The 40-foot wooden sampan Boom Boom went aground at about midnight Tuesday, authorities said.

Durnin said the vessel is about half a mile seaward of Heeia Pier and a quarter- to half-mile south of the Ahu o Laka sandbar.

The state Department of Land and Natural Resources has given the owner of the vessel until 10 a.m. today to remove the Boom Boom.

Department spokeswoman Debo­rah Ward said the owner has told state officials that he doesn’t have insurance or the financial means to remove the vessel.

Ward said state officials are obtaining bids from salvage companies for removal of the craft.

Boom Boom was sold by the owner of Boom Boom Sportfishing LLC about 18 months ago, the former owner said.

State officials said they’re still working out a tangle of owners involved in buying and selling the vessel.

State officials also have given the owner of a 36-foot boat aground on rocks in Wai­anae until 11 a.m. today to remove his vessel.

Ward said the boat owner has contacted a marine salvaging company.

State officials said that vessel went aground sometime Monday.