A retired civil engineer believes the state should ditch several of its Puget Sound ferries and replace them with tunnels.

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Washington State Ferries is developing a Long Range Plan and replacing old docks as the government agency prepares for the next 20 years of growth. But the system has an aging fleet. According to the state’s own fact sheet, all but 13 boats are over 30 years old.

Additionally, the state set aside $600,000 in its transportation budget to study the conversion of ferries from diesel to hybrid-electric.

But Bob Ortblad argues the state should be looking at diving under the Puget Sound, eliminating the ferries that serve Central Puget Sound.

During a Washington State Transportation Commission meeting on Tuesday, Ortblad argued that Japan, Norway, and other nations have dug tunnels for vehicles under large bodies of water. So why not us?

Putting aside the negative connotations of tunnels in Seattle, Ortblad says connecting Seattle with Kitsap County would reduce time spent commuting and be better for the environment. He said it would cost up to $800 million and take up to four years to build.

Tunnels from Smith Cove in Seattle’s Magnolia neighborhood to Highway 305 on Bainbridge, Ortblad suggested, may be a perfect location. They would be about six miles long and descend more than 700 feet below Puget Sound.

Once complete, the cost to maintain the tunnels would be less than repairing ferries, he said.

The tunnels, in Ortblad’s mind, would be tolled. It wouldn’t cost much more — if more at all — than driving across on the ferry now. They would pay for themselves in a decade, he said.

The benefits, he says, are reducing travel times to and from Seattle for people living west of Puget Sound; reducing ferry-related traffic backups on Bainbridge; allow Bremerton to reclaim its parking lots for development. Ortblad says it would also have less of an impact on Puget Sound wildlife and create less noise than the ferries.

Of course, there are many points to argue.

For one, wouldn’t a tunnel exacerbate Seattle’s traffic problem?

Ortblad admits it may not help. A form of fast transit would need to be created to reduce single-occupancy vehicles. The passenger-only ferries being established from Kitsap would allow those who work downtown to avoid the tunnel altogether, a member of the Washington State Transportation Commission pointed out.

It was pointed out that such a tunnel system would have to be tolled heavily to prevent people from flooding into the city on a daily basis.

Ortblad has pitched the idea in the past. He wrote an op-ed for The Seattle Times last year. In that, he asked readers to imagine twin, two-lane tunnels that allow drivers to go from Seattle to Bainbridge in less than 10 minutes for less than $10. It would allow 6,000 vehicle trips per hour for 24 hours a day.

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Ortblad points out the state has paid for similar studies in the past. In the 1960s, engineers recommended a Fauntleroy-Vashon-Southworth bridge. Another study, he says, found that Puget Sound is too wide and deep for a tunnel. However, he argued last year, technology has made advances.

He acknowledges that many people scoff at the idea of tunnels under Puget Sound. But Ortblad points out that people laughed at Homer M. Hadley, the man who conceived the floating bridge across Lake Washington.

“… Homer Hadley was laughed at when he proposed a floating bridge,” Ortblad said. Years later “it was built.”

“Skeptics will laugh. But 20 years from now, electric buses and cars will be crossing under Puget Sound.”