Japan Coast Guard divers prepare to explore the seabed April 26 after a local fisherman reported seeing a large object on the seabed in his fish finder near the Kashuni Falls of the Shiretoko Peninsula in eastern Hokkaido, where a missing tour boat sent an SOS on April 23. (Kenji Notsu)

The Japan Coast Guard cautiously announced that a local fisherman had spotted a large object on the seabed close to the last known position of a tour boat that went missing off eastern Hokkaido four days ago with 26 people on board.

It dispatched divers to the site on April 26, but rough waves compromised their safety and the search was halted.

Officials said the divers went 30 meters deep, but found nothing that indicated the boat. Deteriorating weather conditions made it uncertain when another attempt can be made.

The fisherman sighted the object in his fish finder lying about 30 meters below the sea surface, raising hopes the boat had been found but also fueling growing concerns about the fate of 15 people still missing. Eleven bodies have been recovered so far.

April 26 marked the fourth day of the rescue effort coordinated by the Japan Coast Guard and Hokkaido prefectural police. Authorities said 21 patrol vessels and nine aircraft were deployed in the operation, joined by many local fishing boats.

The area of the object detected is close to where contact with the boat was lost after it sent an SOS on April 23 to say it was taking on water in rough weather.

Authorities widened the search area off Cape Shiretoko on April 26, but said worsening weather conditions forecast from the evening could complicate matters.

Eleven bodies had been recovered as of late April 24, but none since then. Two of the 26 people on board were crew members.

The victims identified so far were given as Yosuke Kawaguchi, 40, of Marugame, Kagawa Prefecture; Yu Nudeshima, 34, of Matsudo, Chiba Prefecture; and Nanako Kato, 3, of Tokyos Katsushika Ward.

The Japan Meteorological Agency forecast strong winds and possible rain later April 26, dashing hopes of making much more progress in the search for a while. Even worse weather is forecast for April 27.

According to the transport ministry, the tour boat, Kazu I, was cleared of any irregularity in a yearly inspection carried out April 20.

Inspectors from the Japan Craft Inspection Organization, which carried out the inspection for the ministry, examined the boat’s exterior and interviewed the owner about possible damage since the boat ran aground in shallow waters in June last year. No new damage was detected by the inspectors, according to the ministry.

Relatives of the passengers and crew who raced to Shari, from where the boat departed for the tour expected to last no more than three hours, clamored for information on their loved ones.

“Too little information,” a man whose nephew was aboard lamented when interviewed on the morning of April 26. “I just pray he will be discovered soon.”

Three briefings for family members on the search effort by officials from the transport ministry, Shari town and the Coast Guard were scheduled for April 26.

A man was seen laying flowers on a stand at a makeshift morgue set up in a Shari town gym.

Nine bodies were laid out. Four of them had yet to be identified as of 10 a.m. on April 26.

Fifty of so grieving relatives visited the gym between the night of April 24 and late April 25.

The Coast Guard’s hydrographic survey ship Tenyo was expected to leave Tokyo on April 26 to assist in the search for Kazu I, which is now assumed to have sunk.

The 430-ton Tenyo will be deployed to search deeper areas of the ocean with its sound beam technology.

The Tenyo, which is 56 meters long, is capable of examining the seabed to depths of 200 meters. It is expected to take a few days to reach eastern Hokkaido.