I am going to make an outrageous but not impossible interisland travel proposal. I know the Superferry failed, but no one has given me a credible explanation. I personally think somebody scammed somebody, but wonder how anyone profits from spending
I am going to make an outrageous but not impossible interisland travel proposal. I know the Superferry failed, but no one has given me a credible explanation. I personally think somebody scammed somebody, but wonder how anyone profits from spending $240 million for a high-tech boat and then abandoning it. I suppose the boat-builder did OK, but Hawaii got stuck for $60 million in harbor improvements.
A cable to transmit geothermal electricity to Honolulu was first proposed by the Kalakaua administration in 1881 and opposed by NIMBYs ever since. Some say it’s impossible to lay a cable from Hawaii to Honolulu, but it’s already been done, twice. There is also a power cable from Iceland to Scotland in the ice cold, 2-mile-deep water via the mid-Atlantic volcanic ridge region of the world’s roughest ocean. Virtually every part of the cable proposal is mature technology you can buy like an appliance.
Cables cross water three ways. Under a mile: hanging from towers on each side. Up to about 100 miles: As part of a bridge or tunnel. Much longer distances: lying on the bottom. Bridges come in many varieties depending on technology, geography and economics: Single span, multiple span, and trestle to generalize.
Once you have bridge over an obstacle there are many options. Some bridges carry traffic, streetcars and railroad trains. Once it’s there it’s a simple matter to add cables and pipelines. If the water is too deep for a conventional bridge the usual answer is a tunnel, or occasionally a floating (pontoon) bridge.
Bridge building is expensive. The Century City Freeway, mostly elevated, cost $1 million a foot, but much of that was land acquisition. Our beloved Department of Water Supply estimates putting a water line underground here costs about $2 million a mile. Highway projects here run about $10 million a mile.
Have you figured out where I’m going? Build a bridge or tunnel system from Big Island via Maui to Oahu. To keep costs less than astronomical it would, like the English Channel tunnel, be railroad and to keep cost even lower, narrow gage, single track. Just big enough to accommodate intermodal containers, cars and pickups on flatcars.
The big but not only challenge is water depth, 6,000 feet. The deepest existing ocean traffic crossing, the Eiksund undersea tunnel is less than 1,000 feet below the surface. The channels here are too rough for a floating bridge. Here comes the radical idea, a submarine tunnel. It would start as a pipe on the ground extending into the sea to a depth of about 100 feet, deep enough for the largest ships to pass over. Beyond that water depth it would be a buoyant structure, but anchored to the bottom, like a tension leg offshore oil platform. As crazy as this sounds (no crazier sounding than Elon Musk’s Boring Company plan) there is nothing about it that has not already been done somewhere.
The other big issue is cost. At $10 million a mile for the first 30 miles it’s probably not economically viable, unless we can get Donald Trump to pay to put his name on it. On the other hand, the submarine parts have no land acquisition cost and no NIMBY constituency to object. The channels are not popular bottom-fishing zones. The underwater part might not be as expensive as a surface road because it can be factory built in segments, and remember, narrow gage. That means a pipe only 12 feet in diameter and on land a right of way as little as 8 feet wide compared to a two-lane highway 24 feet or more. As I said in the beginning, it sounds radical, maybe even crazy, but crazier things that were proposed in the past are part of our reality today, like telephones and air travel. Anyone know Elon?
Ken Obenski is a forensic engineer, now safety and freedom advocate in South Kona. He writes a semi monthly column for West Hawaii Today. Email obenskik@gmail.com
