Lady Jan steam tug

Hi Mark,

The bypass valve is manually operate and allows the flow from the pump to divert back into the tank, but if only opened a small amount less water is fed into the boiler.

I will try & find a loco pipework diagram to show the layout.

The 2 pin coupling you have will always be noisy, a Huco type of coupling would be much quieter.

Is that just painted string lagging? Or asbestos string wound round the pipework, maybe worth a check!

Regards Ray

I’ve now finished the boat. I’ve put a bypass valve between the water supply tube and water tank and rerouted the exhaust straight up the chimney. I turned the brass fittings on my Myford lathe and silver soldered them to the copper pipe. I’ve had it running on compressed air and there are no leaks. I notice the non-return valve on the side of the boiler at the end of the water supply tube does not totally seal. Is this normal? It’s only a steel ball bearing seating on a brass conical surface so I guess it won’t be a 100% seal. I’ve correctly aligned the engine and prop shaft which has made the coupling a lot quieter. Next job is to steam it and see if I can adjust the non-return valve to keep the boiler water at a fairly constant level. I’ve tested the boiler in the middle of the paddock to 140psi and the safety valve blows at 80 psi so I’m happy the boiler is safe.

Ray, I’ve checked the pipe lagging and it is just painted string. This makes sense as my Dad built it from 2005 onwards many years after the dangers of asbestos became well known. I now need to get the boiler certified, does anyone know of someone that could help? I live near Derby but would have no problem travelling if there is no one local.

Hi Mark,

Glad to hear your progressing with your tug 👍 the non return valve on the boiler is called a clack valve which you could get a replacement from somebody like Blackgates or as you have a lathe you could re-seat with a D bit and reseat the ball with a sharp tap with a drift and throw the ball away and use a a new ball.

Hope that makes sense 😀

Regards Ray

Mark,

Steam boiler testing is a problem unless you join a club who has an MPBA boiler tester. It would be a case of asking around the local clubs and probably having to join.

The Kirklees Club have a steam day when boilers can be tested, providing the necessary information is provided in advance. This event is usually in April, but was cancelled this year due to the Covid-19 restrictions. There are two members of this forum who could provide further help, Richard Simpson and Stan Reffin and it could worth sending them a message. Stan has the forum name Gambier Bay. Richard doesn't always respond quickly, as he works away at sea. On their club site, the information is in the 'Downloads' tab on the toolbar. I realise this is a long wait and with my steam paddle tug, I fitted a temporary electric drive installation in order to have some on-the-water time.

**LINK**

Whether one of the commercial boiler makers e.g. Clevedon Steam or Ribble would offer this service, I just don't know.

Tony

Hi Mark,

Where are you intending to run the boat ?? You only need a certificate normally at a club where the public maybe around, you have tested the boiler to your own satisfaction very well by the sound of it.

I run steam locos in the garden no need to have a certificate  there 😀

Regards Ray

Edited By Ray Wood 2 on 20/07/2020 20:08:42

Thanks for the replies, I’ve sent messages to Richard and Stan so I’ll see what they come back with. I’ve read through the notes on the Kirklees club website and I’m a bit concerned that I have no paperwork confirming inspections were passed during the manufacture of the boiler. Does this mean it can never be certified? I’m not sure where I’ll sail it, I don’t have access to a private pond so I really do need to get it certified if possible.

For the non-return valve, I’ve ordered some 5/32” stainless 316 ball bearings so I’ll have a go at cutting a new seat in the housing and getting it to seal.

Hi Mark,

All is not lost, but you will need a model engineering club boiler inspector to see it under hydraulic (water) test and do a visual check for weeps etc , so you may have to join a club to get the test carried out, many engineering clubs have boating sections.

Now you can see why electric power is so popular these days!!

We had a steam boat at my club last weekend all the requirement was that the safety valve was seen to work.

Regards Ray

I like a challenge and being a mechanical engineer steam has always fascinated me. I’ll get more pleasure from working on it than sailing it but it would be nice to take my son down to the water as it was originally made for him when he was about 10 years old.

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Time for an update. I thought the tug was finished, so I tried it on compressed air to test out the modified water feed system. I had to bleed the water pump first. I did this by applying a vacuum pump to the bypass water pipe. This drew water through the feed pump and bypass valve. I left the transparent vacuum pipe in the bypass loop so that I could see what was flowing if anything. I fitted a new non-return valve from Macc Models so I also wanted to make sure that was sealing correctly.

I then ran the steam engine on compressed air to drive the water pump. Adjusting the bypass valve worked fine with it allowing varying amounts of water down the bypass pipe. There was however a problem with the water pump leaking past the graphite string. I took it off and noticed that the cylinder and thread that holds the gland for compressing the graphite string weren’t coaxial. Also the clearance between the piston and cylinder was about 4 thou. I bored out the thread in the water pump body by mounting it on a bar I machined to be a good fit with the cylinder in order to guarantee concentricity. I then made an interference fit insert which pushed into the counter bore I’d machined in the pump body. This was threaded on the inside for the gland. I then cleaned up the cylinder and collar with an adjustable reamer and made a new piston with less that 1 thou clearance. Packed with fresh graphite string the pump now works fine with no leaks.

I then steamed the boiler which highlighted a few more problems. First when the engine is running it seems the exhaust chokes off the chimney and forces the burner flame to back-up and not go down the boiler flue. When the engines not running the flame goes straight down the flue. As shown in this picture the 1/4” exhaust pipe goes into the chimney where it turns 90 degrees before ending. I thought this would actually cause a draft up the chimney but seems to cause a blockage, anyone any ideas?

The second problem was steam consumption. Even when the engine wasn’t running the boiler was struggling to get above 20 psi unless I closed the delivery valve off on top of the boiler. It seems the changeover control valve is leaking. I now need to take that apart to see if I can improve it. Also the piston valves on the engine are leaking. Is it normal for these valves to fizz a bit on the top of the engine?

So plenty of work left it seems.