From Strawberry Patch To The Ocean Chamberlin 47 power cat.

In the months since the launch of the first Chamberlin 47 power cat, her owner and designer have been assessing the efficiency of the whole package, and are shortly to prove the real-life benefits of their three year building project out on the wide expanse of the ocean.

Forget pretty line drawings and dock-side parties, this maiden ocean voyage will prove the outstanding practicality of this Chamberlin design.

Built at Henry Roy’s waterfront strawberry farm on Pumicestone Passage, north of Brisbane, Foreign Affair is the culmination of many years planning for owners Bill and Sandy Brosnan. Having investigated various power cat designs, they decided none of the stock options met their specific criteria. Robin Chamberlin, the respected hands-on multihull designer, was handed his first power cat commission; a clean sheet of paper and a demanding list of requirements.

Efficiency innovations were a high priority as this cat would be going places; it was not destined for life as a marina-bound party boat.

Chamberlin, chosen as much for his personal ocean sailing experience as his design track record, put his more than 100,000 sea miles of experience into drawing the lines, concentrating on drag resistance above and below water, and clean underwater shape. Lightweight construction methods were ruthlessly applied in order to meet the payload specifications of the owner.

Bill Brosnan laboured alongside professional builders Bruce Arms and Sean Coleman in bringing his and Sandy’s dream project to fruition.

While Bill got his hands dirty at the shed nestled in amongst the strawberries, Sandy continued teaching in Brisbane as both worked towards a new life in retirement. The South Pacific islands were beckoning, and they were ready for overseas cruising.

At midnight, June 17th 2003, as the high tide crept up the banks of Roy’s strawberry farm, Foreign Affair lifted off the trailer early and floated well above her lines to the absolute delight of both owners and designer.

Several days later, after the obligatory celebrations wound down, initial sea trials were performed. With just two 100 hp Yanmar diesel motors, and a payload of 2.6 tonnes, a top speed of 21 knots was achieved.

At economical cruising power achieving 15 knots, fuel flow indicated a range sufficient to cross the Tasman Sea to New Zealand – and return halfway home!

Fine tuning of propeller combinations over several months has refined the results.
In the months since launching, the Chamberlin 47 has averaged a fuel usage of just 0.8 litres per nautical mile in general use.

“ Foreign Affair has met all my requirements,” said Bill Brosnan. “And it was a very demanding list to meet!”

So excited are the owners and designer, an ocean passage shakedown of more than 1000 nautical miles is planned for February 2004 to demonstrate the advantages of the Chamberlin 47 in real-life offshore conditions. Data collected on this voyage will put beyond question the advantages of this design.

“ She proves the long-range practicality of a true displacement power cat,” said Chamberlin. “More of these designs have already started construction. Displacement cats like this are the future of efficient power boating.”

Specifications:

LOA 14.25 metres
DWL 13.90 metres
Beam 6.53 metres

Motors 2 x 100hp Yanmar 4HTE
Fuel tankage 1940 litres
Water tankage 1100 litres

Average passage making payload 3600 kg.