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The Warrego is the first marine engine we began designing in 1988 and in 1989 produced the tooling and manufactured the first prototype. The number one engine was a 3 inch bore by 4 inch stroke slide valve with a slip eccentric for reversing, however there were only a few of these engines manufactured before we added the option of Stephenson's link reverse with variable cut off.
In the late 90s we designed a piston valve version with a bolt on valve cylinder in place of the slide valve chamber which proved very successful, but as our orders from overseas were coming thick and fast the decision was made to tool up for a fully cast monoblock piston valve cylinder with inside admission and through valve exhaust to curb manufacturing costs.
Using an operating pressure of 110 psi (8 bar) they will deliver around 5 horsepower at 500 rpm on wet steam which makes them capable of driving a hull of up to 23 feet such as the Elliot Bay or the similar Philip Bolger boat providing it is not too heavy and has reasonably fine lines.
Apart from that not much has changed over the years, the bedplate is an iron casting that is line bored to take standard metric 6206 contact sealed ball races and the crankshaft is supported on four of these bearings which makes for a very strong bottom end with a long life but, by the same token should the boat have the unfortunate occurrence of spending some time on the bottom it is an easy task to remove the crankshaft slide the circlips off and fit new bearings.
The conrod is cast alloy similar to what is used in mag wheels and employs a split bronze bush on the big end, running on a steel crank pin while the wrist pin is of the stirrup configuration with two bronze bushes running on a hollow hardened steel pin, which is plugged at both ends to allow for filling with oil to lubricate the joint during operation.
The cross head is an alloy block bolted to a steel slide which runs in the cast iron slides that are machined into the back column with bolted up keeper plates to retain it while in reverse. This component is lubricated with a small comb which dips into a little tank at the bottom of the stroke and then drags the oil up the slide ways. The big end bearing is a split bronze bush which takes it's lubrication from a sight feed drip oiler that leads oil via a tube into an aluminium flinger on the crankshaft and thru drilled galleries to the crankpin. The flywheel is approx 12 " (300 mm) diameter.
The engine pictured has a long series bedplate which is very handy to have when it comes to bolting on your feed pump but we can supply them with that section of the casting trimmed off.
The S L Reverse has a computer machined expansion link with bronze bushes inserted for the 3 pins which are all pre hardened linear shaft retained with circlips. The link is drilled with holes leading to the bronze bushes for lubrication.
The engines come fitted with drain cocks for warming thru and auto pressure relief valves on the cylinder to guard against problems of lock up due to either condensation or a slug of water coming over from the boiler if you are out in rough conditions.
Being a piston valve engine they have a much higher efficiency than a slide valve unit as they incorporate inside steam admission with through valve exhaust so there is very little load on the reversing link gear which inturn makes for a much quieter running engine with a much longer and more reliable service life. They weigh approx 150 pounds (75 kilos)
The overall engine sizes are similar to those shown for the Swan and Hastings on the next page.
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