For some time now - actually for the past decade - there have been some strange boats humming around the Columbia River between Portland and Vancouver. They can go really fast, yet at other times they can barely be seen. Finally, the mystery's been solved: they're actually three generations of stealth sleds for Navy SEALS.
The already low-slung Alligator has the ability to lower its draft to the point where the cabin windows sit right above the waterline via flooring ballast tanks located on each side and below the boat's main cabin. This results in the boat not only being very hard to spot on radar but it also challenging to spot visually. The streamlined hull and low drag design, along with some powerful water-jets, allow it to move at high speed, especially when its ballast tanks are empty.
First deployed in the mid-1990s, the Alligator class has been supplanted by the Sealion and then Sealion II classes. The Sealions can reportedly hit 40 knots in normal conditions and at least 30 knots in heavy seas. They're bigger and faster than the Alligators, but retain the semi-submersible feature. They also sport a roomier interior cabin and a rear bay capable of holding two raiding craft with retractable door for rapid access and egress.
So what are they doing on the Columbia?
They're doing shakedown runs. These things are built by Oregon Iron Works.
