Page 60: of Maritime Reporter Magazine (November 1998)

WORKBOAT ANNUAL (Continued, from page 49) spot on a Z-drive application would probably be in the range of 22 degrees. The wide, flat hull amid- ships has its advantages, though, as it provides a very spacious engine room layout.

Leverage for the German- designed propulsors is provided by a large skeg mounted on the keel line aft. The design of the skeg is critical as to shape, size and loca- tion because, when driven through the water, it establishes a sheer force that, in combination with the bulk of the hull, is much greater than that of the propulsion system alone.

The business end of the Voith

Schneider propulsors is made up of a rotating blade plate on which are mounted five angle-adjustable air- foil blades. On Crowley's Protector

All the boats in the Whitbread Around the World Race 1997/98 have chosen

Inmarsat terminals from Nera to keep in touch with the rest of the world du- ring this extremely tough regatta.

Nera's well-tested Saturn B and

Saturn C terminals ensure the participants standard phone connecti- ons, fax, e-mail and video recording transmission.

By the end of 1997 Nera had delivered nearly 2 000 B Marine ter- minals, which represents a market share of more than 40 percent

Nera Satcom AS

P.O. Box 91, N-1361 Billingstad, Norway

Tel: +47 67 24 47 00, Fax: +47 67 24 46 21

Homepage: http://www.nera.no

During the autumn of 1997, Nera introduced a new satellite station which is well suited for small crafts and pleasure boats, but also ideal as relief or back-up for larger commerci- al vessels or passenger ships. The

Nera WorldPhone Marine is small, light, easy to use and install, and abo- ve all, affordable.

All Nera Inmarsat terminals are at the cutting edge of operational safety and connection quality.

Nera are the world's leading supplier of Inmarsat stations, with a worldwide service network of subsi- diaries and agents.

OFFICIAL SUPPLIER OF

SATELLITE COMMUNICATION

EQUIPMENT

NERR

TELECOMMUNICATIONS

Circle 307 on Reader Service Card

Changing the way you communicate class these blades, or vanes, mea- sure 6.5 ft. long and 32 in. wide at the top, tapered to 26 in. wide at the bottom. The angle of the blades - from a fully feathered position in which the narrowest part of the blade slips through the water as the plate rotates, to a fully-opened position in which the widest part of the blade is pushed through the water, is adjustable from the wheelhouse.

Under normal operating condi- tions, each blade moves from fully feathered to fully open and back during one rotation of the plate.

The arc of rotation during which the blades open and close is infi- nitely variable, and determines the direction of thrust. The result is tremendous force with very deli- cate control.

All the Voith Schneider propul- sion units used on the Crowley boats were developed and built by

Voith Schneider Hydro Marine

Technology of Heidenheim,

German. Beyond their use of Voith

Schneider propulsion, the new

VMS tugs have their differences.

As the major mission of the

Protector class is tanker escort work on the West Coast, they were based on a 120 x 41.5 ft. steel hull supporting a high-visibility wheel house. Both boats are equipped with two Skum fire monitors, each remotely controlled from the wheelhouse.

Water volume for firefighting is supplied by two 6,600 gpm pumps driven off the main Caterpillar 3606 engines. On the working deck of these vessels a Markey Model

DWSS 52 main winch mounted aft carries 750 ft. of 10 in. diameter soft line and can produce a line speed of 125 fpm with a line pull of 25,000 lbs.

The winch does not have clutch- es. Instead, the drum brakes, which can withstand a static line pull of 400,000 lbs., are set auto- matically at the neutral point as the drum rotation moves from for- ward to reverse. The winch also features a tension-monitoring and alarm system that automatically compensates for the number of lay- ers on the drum and gives a digital display in the pilot house.

This tension display is critical when the boat is being operated in the indirect mode while undertak- ing tanker escort. North of the

Nichols yard, Dakota Creek

Industries at Anacortes, Wash, is building two large "Prince William

Sound" tanker escort tugs for 60 Maritime Reporter/Engineering News