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Steam narrow boat President

News from the hole 4 - from 195 - 40 Autumn 2001

During various chats with friends over the last few months, I get the impression that it is still not clear what we are trying to achieve with the new engine. The original engine was a vertical single crank compound The steam entered the high pressure cylinder where it moved the piston up or down, it then exhausted into the low pressure cylinder where it again moved the piston up or down together with a new charge of steam into the high pressure cylinder therefore on each stroke of the piston up or down, high and low pressure steam is used, doubling the power. The exhaust steam from the low-pressure cylinder then entered a jet condenser. This consists of a metal tank divided horizontally. The top section has a tube that sprays cold water onto the steam as it enters. This action condenses the steam back to water which then flows into the base of the tank where a pump driven by the engine sucked out the water and any air and discharged it overboard. The combination of condensing the steam and the action of the pump creates a vacuum which when the exhaust valve opens the vacuum sucks the exhaust steam into the condenser again increasing the efficiency of the engine. hence there was no exhaust beat up the funnel. The operation was virtually silent.

The new engine is a single crank simple engine. It has one cylinder using the steam only once. Therefore it is one stage closer to the original. It would be possible to convert it to compound running by adding another cylinder. It was felt that it would spoil the appearance and possibly reduce the value of the engine, therefore we decided to keep it simple. Could this new engine run condensing? again moving closer to the original. Jet condensers are very old technology not the sort of thing found lying around, they were usually built to order as an integral part of an engine. Whilst it is possible to have one made, the problem then was where would it fit and could we justify the high cost of having one designed and constructed.

We were offered as an alternative a surface condenser. This is a cylinder capped at both ends through which pass a number of copper tubes. The ends of the tubes are enclosed inside a further cap. Cold water is pumped into one end through the tubes and out the other end back into the cut. The exhaust steam is admitted into the cavity surrounding the tubes, where on striking the cold tubes condenses back to water creating a partial vacuum. This water called condensate is then sucked out by a pump, which also increases the vacuum, which again improves the efficiency of the engine and also eliminates the exhaust beat giving almost silent running. One further stage closer to the original.

Another point of concern which I constantly hear is ‘ It won’t be the same without the constant chuff of the exhaust’ People expect it to go chuff chuff. etc. I agree, It won't be the same for the reasons I have already outlined. Remember President or for that matter any other steamer in the fleet did not exhaust up the funnel.

How will it be possible to maintain steam pressure without the pull of the exhaust? is another frequent question. The honest answer is I don’t know. All I can say is the engine should use less steam. Our working pressure will be increased to 150 PSI which greatly improves efficiency. Also the blower is there for that very purpose.

I also will miss the thrilling sound of that characteristic beat which is so much part of the ethos of President. So I intend fitting a diverter valve which will put the exhaust up the funnel, this will, and I emphasise will only be used at rallies or other events where it is appropriate.

In my last article I explained how we are going to fit two Weir pumps to operate the condenser. The work on the first of these is now well advanced. I can assure you all they will look wonderful (lets hope they work).

Work on the boiler is nearly complete. The good news is that it did not require internal washing saving us some £2000. The overall condition of the boiler is excellent. (much to my relief) .

The restoration of the hull is moving ahead. President is beginning to rise from the heap of rusting scrap. A major problem has been sourcing the rubbing strips that surround the hull. The size is none standard. So after much talking, cajoling and begging by our Chairman, Dudley Rolling mill has agreed to do a special run. The new propeller will hopefully be manufactured shortly. This is being done by a company in Holland.

Why a new prop. The new engine is more powerful 15bhp at 170rpm running at 150psi also the old engine ran ahead anti-clockwise. The new engine runs ahead clockwise, so the profile of the new prop will be very different.

There is still a huge amount of work to be done. We are not going to rush it. It will be done to the highest possible standard. So I ask you all to be very patient. I welcome any assistance, and if you want more info please ring me.

Dave Stott