The two propulsion engines to be installed in The Minerva were manufactured by William Sisson and Co of Quay Street Iron Works, Gloucester England.

Our two engines came from a batch of at least 30 that were made for the Admiralty's 52'6" Harbour Service Launches during World War 2.

We believe that these 1910 designed engines were chosen because internal combustion engine manufacturers were fully committed to the war effort and had no spare capacity.

Each engine is of the compound design, having a high pressure cylinder of 8" diameter and a low pressure cylinder of 16" diameter. The stroke of the engine is 8".

The first engine (eng # 4735) we found had just been removed from the original vessel that it had been fitted to back in 1945. In 1960 an American had converted the HSL to a pleasure boat and named her Oceanid. This engine was in very good condition, the only outwork we had done was having the crankshaft metal sprayed and ground to stock size. The overhaul of the engine was done by our volunteers.

We don´t have any records of the second engine (eng# 4614). It required extensive outwork including crankshaft grind, big ends and main bearings remetaled, cylinders bored and pistons built up, new piston rings made, valves refaced. Again our volunteers did the overhaul that included the remanufacture of a lot of studs, pins and bushes. Unlike the other engine, this one had been neglected so there has been a lot of work overcoming rust damage.

They were rated at 80hp at 250rpm. We will operate them at about half that speed.

We made an extensive search worldwide over a couple of years and found a total of seven of the original 30 odd that were made.

We have two Auxilliary Steam engines. One is a Sisson Genset, which has a smaller Sisson steam engine for powering our DC Generator. Our Second auxilliary steam engine is a Howden circulating pump engie to drive the Sea water Condensor Cooling pump.

The restoration of these two units are complete.

The Minerva previously had all the Steam engines driven by steam generated from a Coal fired boiler. The Renovation to The Minerva will have a NEW wood pellet fired High Efficiency boiler.

The boiler was manufactured in Invercargill by Invercargill Engineering New Zealand and was shipped up to Opua where it was lifted by crane and into The Minerva's engine room.

The wood pellets will be supplied by Fletchers Timber mill based in Waipapa to fuel our boiler for the operation of The Minerva.