Page 31: of Maritime Reporter Magazine (February 1998)

COMPANY PROFILE

Safety

Everything we do is governed by safety: safety for your crews, your cargoes, your ships and your environment

Our systems for collecting, compiling and checking new information are leading edge.

Important navigational data is published rapidly through weekly Notices to Mariners, and then incorporated in

New Edition Charts.

Admiralty Charts and

Publications are available around the world, from any r< of our Chart Agents.

We aim to ensure that our charts are fully up to date the point of purchase; thus you can be assured that we always put your safety first!

CHARTS/AND PUBLICATIONS reliability • safety • innovation

The United Kingdom Hydrographic Office, Admiralty Way, Taunton, Somerset, Tfll 2DN United Kingdom Tel +44 (0)1823 337900 Fax +44 (0)1823 284077

Rolla: Advancing Propeller Design Drive Units, Mondrive System and Trimax. In addition, Rolla recent-ly designed and produced forged steel blades for controllable pitch surface propellers. The results

Rolla obtained at the Technische

Universitat Berlin constitute the first systematic series of surface propellers available in the world and permit the company to supply

Circle 283 on Reader Service Card the torque and thrust coefficients and efficiency, horizontal and ver- tical force figures for different shafty inclinations and propeller immersions. The Rolla stainless steel propellers for stern drives include lines specifically designed for ZF-MPM, Volvo Penta,

MerCruiser, Kiekhaefer, Yamaha and OMC.

Foundation Built On R&D

As part of its ongoing dedication to research, in 1993 Rolla became a member of the MIT/Navy/Industry

Consortium on Cavitation

Performance of High Speed

Propulsors. One of the principal objectives of the consortium was to develop efficient computational optimization techniques for the automated design, in the presence of cavitation, of innovative high- speed propulsive configurations.

In general, propellers are pro- duced in high-tensile stainless steel (using investment casting and forging) for very high-speed craft and traditional casting in

February, 1998

University cavitation tunnel and at the IMHEF cavitation tunnel at

Lausanne; full scale tests; pro- peller re-calculation and redesign for existing vessels; designing and manufacturing of propeller proto- types and pre-series; designing of conventional and unconventional propulsion systems; and consulta- tion on propulsion problems. All

Rolla propellers are designed to be dedicated to a particular craft's projected operational profile by using the Rolla proprietary lifting service and panel method pro- grams, and are manufactured using the Catia CAD/CAM pro- gram. A Rolla-associated manufac- turing facility is able to mill pro- pellers up to (9.8 ft.) (3 m) in diam- eter with a five axes MECOF M 1000 milling machine.

Rolla also offers a complete design service for companies inter- ested in the application of surface propellers, specifically for those operators not wanting to use a commercially available drive, but desiring to realize their own pro- prietary system. Rolla will collab- orate with builders in the design of their own system, and will make available more than 30 years of experience in surface propellers and installation.

Founded in 1963 by Philip

Rolla, Rolla Propeller offers a wide variety of services, consulta- tions and designs, including: per- formance and power prediction for displacement and planing craft; propeller design; estimation of complete hydrodynamic character- istics of the propeller geometry, and propeller cavitation character- istics through exclusive lifting sur- face and panel method programs; manufacturing of propeller models; model basin tests in the Berlin steel or NiBrAl for commercial, military, workboats, luxury boats and pleasure boats up to 80 knots.

The Rolla families of stainless steel and NiBrAl surface piercing propellers include lines specifically designed for Arneson Drives, Levi