Brooke ‘Hundred’ Marine Motor and Static Engine-run Calculations

Known as the Brooke Hundred, John Brooke, Grandson of original builder), completed this 40-F/28 in 1997. The motor produces upwards of 103 h.p. at 2,000 r.p.m., and remains the only (and last) retrofit replacement for the Brooke 65-F/10 marine motor.

On the plane at 6-knots, “Smuggler” is able to cruise against both the 14 and 16 knot tides of the River Humber and River Mersey. Her ultimate speed has yet to be determined, but does promise to be fast!

Fright
My first outing with the Brooke 40-F/28 motor was at Lake Windermere in 1997. On engaging the throttle I was immediately hurled back onto the rear thwart, and after a few moments awakened to realise that “Smuggler” was powering through the water. I literally had seconds to act, clawing myself forward up the well-deck to re-engage the throttle as she continued to accelerate through the water picking up even more speed!

“The six-cylinder Brooke 100 h.p. unit below was primarily intended for use in the Brooke Sea-car and Brooke / Brooke-type fast Seaplane Tenders. The bore size of each cylinder being 4 1/4” with a stroke length of 4 3/4”.

‘Engine Build Unit’ Equipment comprises as follows: -

Engine & Reverse Gear (incl. Self-starter equipment)… weight: 1,231 lbs.
Equipment “A” - Comprising; 6-ft. Tailshaft, 3-ft Sterntube and one Propellor… dry weight: 97 lbs. Equipment “B” - Including above but with additional Petrol / Fuel-tank, Water tank, Exhaust piping, Cast-iron silencer, Skin-fittings and Other tools… dry-weight: 270 lbs.

The 1928/30 Brooke Hundred motor seen below was originally shipped from Brooke’s with Twin Zenith Updraft-carburettors, a D.C. electric Starter motor, D.C Generator equipment, an Epicyclic water-pump (complete with taco drive), an Oil filter, and a Hand-starter (provisioned in case of emergency). The output drive-shaft is coupled via a Fenner Taper-lock via an Arrow coupling.

It’s water circulating pump is of the gear-type and the motor is relatively silent in operation. This is partly due to the fact that the camshaft operates via overhead valves through the medium of push-rods driven by a silent chain of a similar type to those used to drive the Electric generator, Water-circulating pump and Oil pumps.  The reverse gear forms an integral unit that is coupled to the engine. Originally, an epicyclic gear type was employed but this has now been discarded in favour of a bevel gearing which has long-since proved satisfactory.

From Left to right… 1 - Magneto 2 - D.C Generator

This motor was originally designed for the Brooke Sea-car and also, to replace ageing 65F-10 marine motors of the many Brooke and Brooke-type Seaplane Tenders that were then still in existence.  It was also used to power some larger Brooke Motor Boats, including early ST200-Class Seaplane Tenders of Hubert Scott-Paine (British Power-Boat Company) at Hythe, England.

D.C. Generator Chain-drive, Starter ring and Clutch Assembly during build…

Short-term engine running heat calculations were detailed by ECS Aero Engineer Andy Stowe, to calculate time duration for ‘static running’ of the Brooke marine motor. These calculations relied upon 1 x 45 Gallon Drum of water to provide 3-minutes 40-Secs. of running time at Max. Power, and based on an assumption that our idle power would be approx. 10% of the heat rejection our run time should exceed 30-minutes!

Engine-Run Calculations…. by Andy Stowe