Page 41: of Marine News Magazine (January 2016)

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INLAND PROPULSION the market.”

Kari Kyyrö, Naval Architect at Steerprop Ltd. is equally optimistic. “Azimuthing units offer signi? cant bene? ts for river operations, where excel- lent maneuverability is usually a must. The market potential is good; however competition is also growing with makers de- veloping products aimed spe- ci? cally at the inland market.

It will be interesting to watch if the U.S. operators will follow the European way and start building more diesel-electric push boats.”

Pollution: OPA 90, and later, the EPA’s so-called Ves- sel General Permit (VGP) both brought increased liability

Mitch Jones photo courtesy of Sneed Shipbuilding through a greatly expanded list of potential sources of leakage from vessels. In response, operators began to look for ways construction cost of a traditional towboat. If a towboat is to eliminate any potential sources of oil leaks. Of course, a designed for Z-Drive units, there is no need for a main en- frequent cause of an oil leak from normal wear or damage gine reduction gearbox, intermediate shaft, tail shaft, shaft was the stern tube shaft bearing or the strut shaft bear- couplings, shaft support bearings, stern tube, stern tube ing, both of which are oil-lubricated bearings. Shearer bearing and a raft of other related equipment. Hence, the and Beers tell us that “all conventional drive inland tow- cost of a new Z-Drive inland towboat will be approximate- boats have a shaft seal where the drive shaft goes through ly the same cost or at most 10 to 12 percent more than the the hull. Over time as the seal wears, water leaks into the cost of a new, conventional design inland towboat (de- boat. On some seals, a small quantity of leakage is required pending on which manufacturer of Z-Drive units is used). to keep the seal lubricated. This causes water to accumu- Brian Fariello, Wärtsilä’s Business Sales Manager, Pro- late over time in the boat’s bilge where it mixes with oil and pulsion, Americas, couches the discussion in a different other liquids from mechanical sources. The boat operator perspective, saying, “Downtime for any commercial vessel then has to keep the bilge or other voids pumped out until is critical. However many inland waterway companies are the boat can be removed from service for drydocking to re- smaller and loss in time or revenue can be very damaging pair the seal. In addition to the loss of revenue, the cost of to their bottom line as well as reputation which could af- drydocking, and the cost of replacing the seal, the oily wa- fect future contracts if they are viewed as having an unreli- ter mixture has to be disposed of properly.” Z-Drive boats, able ? eet.” on the other hand, produce no accumulation of oil or oily Fuel Savings: The Shearer Group’s report goes into a water mixtures in bilges or on the deck of the towboats. great deal of detail on the real and potential fuel savings

Capital Investment and Maintenance: The old rule of achieved by Z-Drive boats versus the fuel consumption for thumb for the cost of new construction of a towboat with a conventional vessel. And, given the current state of oil z-Drive units is to add as much as 25 to 50 percent to prices, some of the ? nancial assumptions (price per gallon the cost of a traditional design. This comes from adding of diesel) made by the report may now be (temporarily) the cost of Z-Drive units to the total cost of a traditional dated, there can be no denying the long term ? nancial im- towboat – but that doesn’t tell the full story. This does not pact that the switch to Z-Drives will have on the bottom take into account the items that are eliminated from the line of any operator. Shearer’s report went on to say, “Z- 41 www.marinelink.com MN

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