From the waterline up, the 72' ⋅ 30' triple-screw tug being
built at Fred Wahl Marine Construction for Ruby Marine in
Nenana, Alaska, isn't much different from boats that work on
the Mississippi River system.
Below the waterline, however, there's a distinct difference.
"She's missing half a hull," said Matt Sweetsir, who heads up
Ruby Marine. That's because the boat, which was designed by
Entech & Associates, Houma, La., only draws 3'6". To get
that shallow, the 38" props are tucked up into tunnels.
"The tops of the propeller blades are just about at the
waterline," said Mike Lee, general manager for Reedsport,
Ore.-based Fred Wahl Marine.
The shallow draft is necessary because of the rivers the tug
and its two 150' ⋅ 40' ⋅ 6' barges will ply. The 72-footer will
push loads of fuel and freight on the Yukon, Kuskokwim and
Nushagak rivers in western Alaska.
Portions of the rivers are particularly shallow in the
spring and fall. "If we don't have three-and-a-half feet, we
are not able to get to all the villages," Sweetsir said.
There are a couple of other aspects to the tug's operation
that aren't found in the Lower 48. Besides seasonal shallow
water, the rivers quickly freeze during the minus-60º winters.
Thus Ruby Marine's tug will either be tucked away in a slough
or hauled up on the beach for the winter.
To prevent pipes from freezing during the winter layover,
the plumbing is designed to be easily drained. "Even if the
runs don't look good, they need to have slope and cleanouts to
get the water out," said Lee.
Between freezes, the rivers are navigable for only about
four-and-a-half months. "It goes from the last week of May to
early October. Five [months] would be great, but I've never
seen it," said Sweetsir.
With such a short season, there's no crew rotation. The crew
that arrives in May stays "until the boat is put away," he
Thus crew comfort is especially important. Lee said there's
a recreation room on the boat. The boat is also
air-conditioned. Granted, the temperature only gets to about
85° for a month, but Sweetsir said he wants to do everything
possible for the crew to get plenty of rest, which can be
difficult when there is daylight 24 hours a day. To reduce
engine noise, the overhead in the engine room has plenty of
The main engines are three 500-hp Lugger diesels. There's
also a pair of 55-kw Northern Lights generators, which will be
used mostly for hotel power.
On the foredeck will be a pair of Nabrico 40-11-14 five-hp
electric winches, along with one Nabrico 40-11-M hand-operated
The all-aluminum house has three levels. The hull, main deck
and trunk on which the house sits are steel. The top of the 3'
raised steel trunk is the engine room's overhead. Without the
raised structure, there would only be 4' between the main deck
and the bottom of the boat, hardly enough space for an engine
The tug will be delivered by early April. Ruby Marine's two
150-foot barges are under construction at Beoufway Contractors
' Louisiana facilities in Houma and Amelia.
- Michael Crowley