Page 70: of Maritime Reporter Magazine (June 2, 2010)

70 Maritime Reporter & Engineering News

NEWS VESSELS

The BRAtt project evolved from Ron

Burchette’s training programs for tug op- erators using radio-remote controlled scale models. Why not build a model that is large enough for the operator and instructor to ride on and learn in the same space frame of reference as the boat?

The BRAtt is a 25.6 ft by 14.7 ft. alu- minum-hulled training tug designed by

Robert Allan Ltd, with the designer’s dis- tinctive double-chine hull form. Under the counter of the broad stern the hull tucks in quickly providing good water flow over the twin azimuthing drives lo- cated aft in the ASD manner. Forward, a relatively deep bow is augmented by a skeg that makes this an escort capable tug. When complete, the little tug will be able to provide real water training to as- piring assist and docking tug masters without taking an expensive full-size

ASD tug off the job. The boat will be fit- ted with a fully operational Braden hawser winch forward with the Samson tow line passing through a polished stain- less-steel staple.

The BRAtt is being built by Adrenalin

Marine Ltd. of Delta, B.C., which has been selected as the licensed builder for all BRAtts in North America. The 450-hp

BRAtt features most of the same tech- nology and operating systems as similar full-sized Z-drive tugs, so operators can be trained to handle the more expensive and larger tugs that have become com- mon in the world’s major ports without putting those major assets at risk.

The propulsion system on the BRAtt is scaled to proportionately represent the full size tugs. It begins with a pair of

Cummins QSB5.9-230 HD engines, each delivering 225 hp at 2,600 rpm into en- gine mounted ZF280.1 gears with 1:1 ra- tios. To allow for further reduction below the engines’ 600 rpm idle, the gears have slipping clutches. Flexible Centa tor- sional couplings are installed between the engines and their gears. Additional flexi- ble couplings are at either end of the drive shafts to reduce vibration and to accom- modate any movement in the flexibly mounted engines. The Z-drives are

Olympic Model HD3 with 2:1 reduction.

The propellers are 25 3/4 inch stainless in stainless nozzles. Both the engines and the Z-drives are mounted with a five-de- gree angle upward to the stern. The 450 hp twin-engined tug is anticipated to de- liver an 8000-pound bollard pull.

Robert Allan Ltd.’s project manager

Michael Burgess said, “We have tried to stay all aluminum for the piping and fit- tings. Where that is not practical, such as the staple on the bow, we have used stain- less. The engine is isolated from the alu- minum with stainless shims.”

Among the many interesting and inno- vative features of the BRAtt are the four bollards built to also serve as lifting points for the 16-metric ton vessel. The wheelhouse will be fitted on resilient mounts to provide a lower ambient noise level in the training area. In operation there will be room for at most three peo- ple on the boat, but ideally just two. In addition to its training functions, the

BRAtt can serve effectively as a real tug, doing smaller towing, docking and line- handling duties, and other harbor tasks such as boom deployment.

BRAtt is equipped with Samson’s

Quantum-12 rope, one of Samson’s most popular towing lines. “Samson is hon- ored to have been invited to participate in this unique opportunity,” said Director of

Sales Terry Crump. “Just like any towing environment, the student tug operator shouldn’t be concerned about the per- formance of the towline. This is why

Samson recommended Quantum-12. It’s extremely strong and it grips better than standard HMPE towlines. Quantum-12 is perfect for this little BRAtt.” Designed as a flexibile and easy handling 12-strand,

Quantum-12 uses Samson’s patented

DPXTM technology, blending Dyneema and polyester to provide high strength, superior abrasion and cut resistance, and greater grip for use on winches, capstans, and H-bitts than other high modulus polyethylene ropes.

Vessel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .BRAtt

Builder . . . . . . .Adrenalin Marine Ltd. of Delta, B.C.,

Designer . . . . . . . . . . . . . . . . . . . . .Robert Allan Ltd.

Engines . . . . . . . . . . . . . . . . . . . . . . . . . . . .Cummins

Z-Drives . . . . . . . . . . . . . . . . . . . . . . . . . . . .Olympic

Couplings . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Centa

Gears . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .ZF

Rope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Samson

Meet The BRAtt

Burchette Robert Allan Training Tug

Photos by Haig-Br own/Cummins Marine