The owner of a 31-foot cabin cruiser that sank early this week said he hoped to find out why it went under. “I hope we’ll be able to get it up high enough to see where the water’s coming in,” Mark Fontenot said Monday evening.

Harbor crew discovered the vessel Toby mostly submerged at the Small Boat Harbor around 8 a.m. Monday.

Fontenot said he checked on the vessel around 3:30 p.m. Sunday and it was “high and flat” in the water. “It was sitting pretty. That’s what the harbormaster and his assistants told me it looked like when they left the harbor a couple hours after that. Something failed in the wee hours of the morning.”

Fontenot said he could have done a more complete job shoveling snow off the vessel after the weekend’s big storm, but he said he’d seen it on previous occasions lower in the water and loaded with more snow. Owners are advised to shovel off vessels during heavy snows to keep intakes above the waterline, but Fontenot said he figured rain that started Sunday would melt off remaining snow. “Something was different this time,” he said.

The vessel was equipped with three bilge pumps, two deep in the bilge and another, higher up intended to serve as a fail-safe. The pumps were connected to the harbor electric grid and should have been functioning, he said.

Some boat owners this week speculated the vessel may have taken in water through the “wet exhaust,” an opening just above the vessel’s water line that lets out water and exhaust fumes when the vessel is operating. Such openings are designed to not allow water to enter a boat, but can malfunction in below-freezing temperatures.

Harbormaster Phil Benner said it’s not unusual for vessels to become swamped when a heavy snow follows a hard freeze. In such situations, temperatures freeze those openings in the open position, and snow loads push those openings under water.

Fontenot said that theory was as good as any, but said the bilge pumps should have been able to keep up with such an inflow. It’s also questionable whether such an intake of water there would have sunk the vessel so quickly, he said.

Harbor employees estimated about 90 gallons of diesel had been recovered from around the vessel Monday. Fontenot estimated the boat held about 150 gallons of fuel when it went down. Staff placed two perimeters of containment boom around the vessel before noon.

“We were out there sucking it up. I feel we were containing the sheen really well,” he said.

Fontenot was hoping to resurface the vessel Monday, but the process was delayed in part because he had to have inflatable bladders called “lift bags” flown up from Juneau, he said.

Fontenot said the Monk Trawler-style design vessel was built in 1984. He’s owned it for 10 years and uses it for recreational outings.

Harbormaster Benner said a harbor skiff used by Pacific Pile and Marine also swamped while docked at the harbor over the weekend.