Rim Driven Propellers

Sea Jet's RIMJET, Advanced Electric Ship Demonstrator

The Sea Jet Advanced Electric Ship Demonstrator (AESD), funded by the Office of Naval Research (ONR), is a 133-foot vessel located at the Naval Surface Warfare Center Carderock Division, Acoustic Research Detachment in Bayview, Idaho. Sea Jet - built by Dakota Creek Industries in Anacortes, Wash. - operates on Lake Pend Oreille, where it is used for test and demonstration of various technologies. Among the first technologies tested was an underwater discharge waterjet from Rolls-Royce Naval Marine, Inc., called AWJ-21, a propulsion concept with the goals of providing increased propulsive effiency, reduced acoustic signature, and improved maneuverability over previous Destroyer Class combatants.

In a program of research and development which was years in the making, Office of Naval Research (ONR), Rolls Royce Naval Marine Inc. (RRNMI), and the Signatures Department (Code 70) prepared the demonstration of an advanced waterjet-based propulsion concept, named AWJ-21. RRNMI, Walpole, MA, has developed the AWJ-21 propulsor concept with the goals of providing increased propulsive efficiency, reduced acoustic signature, and improved maneuverability over DDG 51 Class combatants. For this demonstration, a 130-foot-long craft designated the Advanced Electric Ship Demonstrator (AESD) was built. The AESD is being funded by ONR to demonstrate advanced electric ship and propulsor technologies. The ground-breaking demonstration is sponsored by the Office of Naval Research. Additional benefits from the AWJ-21 technology are expected to provide more compact propulsion systems with reduced weight and volume.

The AESD is an approximate quarter-scale destroyer class combatant with a length of more than 133 feet and a full load displacement of 120 tons [239,000 pounds]. The AESD hull form is based on the 5565 tumble-home hull tested early in the DD(X) program. As a result of availability of the AESD demonstrator craft, planning is underway to conduct other technology demonstrations. One such effort is the design of a low signature deckhouse for the model.


On 30 November 2005 the Advanced Electric Ship Demonstrator (AESD), Sea Jet, tied-up to the pier after completing its first day of sea trials on Lake Pend Oreille at the Naval Surface Warfare Center Carderock Division, Acoustic Research Detachment in Bayview, Idaho. The ship would test Rolls-Royce patented AWJ-21™ waterjet technology over the following six months on Lake Pend Oreille at the Navy’s Acoustic Research Department in Bayview, Idaho. The AWJ-21 is designed to increase ship speed, making hulls sleeker by working without rudders, shafts and propeller struts. Unlike conventional waterjets, the system works completely underwater, reducing noise and surface wake and improving stealth. The lightweight and compact AWJ-21 allows ships to operate in shallow waters. Its integrated steering and reversing system improves maneuvrability at low speeds.

Carderock Division’s Acoustic Research Detachment in Bayview, ID, is where most of the testing commenced in FY 05. Members of Philadelphia’s Code 90 supported machinery and electric drive quieting for the AESD. General Dynamics Electric Boat division similarly applied its expertise to the electric drive propulsion system. ARL at Penn State provided test support for the early waterjet development, and MIT assisted with the waterjet pump design. Computer Sciences Corporation (CSC) is responsible for the overall AESD boat design.

The RIMJET is a novel type of podded propulsion system that relies on a permanent magnet motor to drive the propeller, making it similar to the systems featured in this issue of Solutions (p32). In the RIMJET propulsor the motor is mounted not in the hub but in the rim, which GD Electric Boat believes provides a number of advantages. One of these is that because the RIMJET makes use of the same hydrodynamic principles as a waterjet, its applicability to high-speed vessels is much greater than conventional propulsors. Advantages over waterjets include high rotor torque capacity, rim attachment of rotor blades, minimal hull contour impact and azimuthing capability. The RIMJET’s high efficiency derives from its use of a phenomenon known as swirl recovery. Moreover, because it operates at a relatively low rpm, blade area is reduced, there is minimal duct and strut surface area, and the propulsor has low duct and strut velocities compared to hub-driven propulsors. The RIMJET has excellent cavitation performance because it operates at low rpm, it has very uniform inflow to the rotor, and the rim prevents the formation of tip vortexes. General Dynamics believes the RIMJET will also have better ‘off-design’ performance characteristics because the duct provides uniform mass-flow at off-design conditions.

It also promises to be much more reliable and maintainable than hub-driven pods. GD Electric Boat says the ‘canned’ permanent magnet motor at the heart of the RDP and stator are both sea-water cooled, eliminating the need for a cooling system and anti-condensation heating system. Having a seawater-lubricated journal and thrust bearings removes the need for a bearing lubrication system and seals, and having the strut outside the propeller wake reduces cavitation erosion. The duct also shrouds the ship’s hull from blade-induced pressure fluctuations.

Ethereal launched with Hubless Thrusters

This is Ethereal, a Ron Holland-designed 190ft ketch just launched from Royal Huisman in The Netherlands for Americans Bill and Shannon Joy. Just another superyacht, you may say, but this yacht's hybrid power system represents something very different and this unusual picture of her seemingly gliding across a 'sea' of green is significant.

She is seen here manoeuvring along the Dutch canal system en route to the open sea for trials where her she was put through her paces at 10 knots under power with no internal combustion engine in use. Instead she was using her lithium battery bank of 400kWh, designed to keep her running for a day with most of her onboard systems in use too. These batteries drive a Combimac electric motor/generator which rotates the shafts and then charges the battery bank when the yacht's more conventional twin Caterpillar 533kW diesels are brought into play.

She also has two 177hp electric Van der Velden hubless thrusters which can turn the yacht through 360 degrees in just 1min 40sec, not bad for a yacht weighing almost 500 tons!

According to Mike Koppstein of Huisman, the silent running mode is quite unnerving with no engine noise or vibration while 'motoring' with electric power. The same goes for the hubless electric thrusters.

Ethereal is currently undergoing sea trials in the North Sea.

I must correct a possible misconception I may create here. The 'thrusters' on Ethereal are just that, retractable trusters, NOT propulsion units.

Royal Huisman Shipyard is currently building a 58.04 metre (190.4’) performance Ketch Sailing Yacht, designed by Pieter Beeldsnijder Design with naval architecture by Ron Holland Design. This prestigious yacht is to be delivered in 2008 and will be equipped with 2 EPS™ 800, 132 kW retractable thruster units. The EPS™ bow and stern thrusters offer extremely low noise levels and an excellent power-performance ratio. The retractable EPS™ version is designed to suit the specific needs of sailing yachts. An uninterrupted hull shape helps keep drag to a minimum and the retractable EPS™ will contribute to smooth sailing.

What's Up

It appears as though some of this development work on both the trusters and the propulsion units has stalled out along with the world's current economy.

I went looking today for some updates, and here are a few items I found along the way:
http://www.eee.manchester.ac.uk/pdf/research/pgr_conference/PTuohy.pdf

http://www.ship-technology.com/projects/olympic-octopus/

http://publishing.yudu.com/Ab9xx/WTMay08/resources/5.htm


http://www.riam.kyushu-u.ac.jp/ship/ittc/presentation/PPT-Propulsion.pdf

http://ammtiac.alionscience.com/pdf/WQV9N1_ART04.pdf

http://www.globalsecurity.org/military/systems/ship/dd-x-sea-jet.htm

First ship with Azimuth Rim Driven Thrusters/Propulsion

The M/F Eiksund, a RoRo car and passenger ferry of LOA 160 ft (49 m), beam 34.7 ft (10.6 m) and draft 10.2 ft (3.1 m) was built in 1970 and originally powered by a single Wichman 552 kW (750 hp) diesel engine with mechanical drive to two propellers.

She has been repowered with a new propulsion system consisting of two new diesel engines driving Permanent Magnet (PM) generators and two Brunvoll RDT1500 azimuth RDT which is the world’s first commercial application of this type of drive. Control and management of the generators and propulsion system is provided by Inpower, Norway.

Maritime Propulsion | First ship with Azimuth Rim Driven Thrusters enters commercial service

Passenger Vessels and Yachts to Use Voith Thrusters

Voith currently is the only manufacturer world-wide to produce thrusters with a power of 1 500 kW based on permanent magnet synchronous machine technology (RIM drives). Recent orders for offshore applications, passenger vessels and yachts underline Voith’s position as global market leader for these systems.

...from a submission on another forum

QUOTE=MechaNik

Ocean Yacht systems are offering a rim drive thruster now too, possibly someone elses design to start with.
Rim Driven Thrusters by Ocean Yacht Systems - world leading suppliers of thruster and control systems to the superyacht and high performance yachting market.

The difference here is that they use a more conventional prop with a centrally supported thrust bearing. This could be key in resolving long term thrust support issues when used as primary propulsion.
Four sizes 15,48,133 and 260kw in various formats.

OYS | Rim Driven Thrusters by Ocean Yacht Systems - world leading suppliers of thruster and control systems to the superyacht and high performance yachting market.

I just happened across this extensive PDF tonight, but have not had time to review it yet. Just didn't want to lose it, so posting it here..

....opps to large to attach, so here is link:
https://www.escholar.manchester.ac.uk/api/datastream?publicationPid=uk-ac-man-scw:134227&datastreamId=FULL-TEXT.PDF

KaiserWerht 45M

In cooperation between KaiserWerft and Voith a new 45m project has been initiated. The Evolutionary project with Electro Magnetic Propulsion System will be first Mega Yacht application in the World on our 45m project

KaiserWerft. Welcome to the home of Mega Yachts.

Just found myself mentioned on this Youtube presentation

Just recently a gentleman has added some discussion that deals with rim-drive over on this other subject thread:

http://www.yachtforums.com/forums/technical-discussion/2229-diesel-electric-propulsion-10.html#post171971

I've invited him to post some of his observations on this particular subject onto this subject thread, rather than continuing those rim-drive related discussions over there.