Category Archives: The Power Plant

Building the Engine and Boiler
Below are posts related to the building of Arthur Leak’s marine compound steam engine as originally described in Model Engineer magazine and more recently provided via Camden Books (drawings, manual and castings). It will also include the construction of a oil-fired Yarrow watertube boiler, to designs from John King from the SBA (see links on right of home page)

This is the engine that will power SY-Befur, it is expected to produce 10-14HP. These post cover all the construction from Camden’s castings and the addition of pump and alternator assemblies for our particular installation.

Lifting the Boiler In

With the snow too deep to open the doors today, a few words on the last couple of weeks work seem appropriate.

We are still working towards an April launch, but there is a fair amount still to do.

Cabin and Cockpit Soles

We were lucky enough to have some oak (new) and mahogany (very old) floor-boarding donated to the project. So the cabin has the oak and the cockpit the mahogany. This involved assembling the boarding into “blanks” and then spilling and cutting the required shapes from the boat.  (it also involved wrecking a set of planer blades when I missed a couple of old staples in the mahogany) This inevitably requires a deal of tooing-and-froing and careful adjustment. We opted to lay these directly on the floors, while we could have gotten them an inch or two lower, the trade-off of headroom, stability and work mitigated towards the simpler option.

Clamping the boards into a blank

Cockpit sole ready to fit

We also decided to make the sole plates around the engine and boiler of aluminium chequer-plate. This would provide a better under-foot grip and withstand the heat/oil better than wood. We used 3mm plate reinforced with 30mm x 50mm x 2.5mm  aluminium angle pop-riveted underneath.

It all looks quite neat.

Installing the Boiler

Much earlier in the process I made a mistake in fitting the funnel “permanently” to the casing. It’s quite neat but makes handling the boiler rather hard. We concluded that we needed to use two chain hoists (one for each side) to stop the chains fouling the funnel. The same process of  lifting the boiler then sliding the boat underneath. It actually took two attempts to get enough lift to clear the cockpit sides, but went fairly well…

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The boiler is mounted on four lengths of 50mm steel channel (two fixed to the bottom of the boiler casing in the “n” position and two attached to the bearers in a “u” position. We opted to notch the floors to get the boiler and inch or so lower in the boat, and ran it as far astern as possible to provide the best access to the cabin hatch. (Sorry for poor quality of pictures – the barn is quite dark).


The planning worked and there is just room for the battery to sit fwd of the boiler in-between the boiler bearers. We opted to put the boiler pressure switch inside the cabin (being 240v and all!) and fixed the switch/fuse panel to the aft cabin wall, so now we are just wiring up, and trying to make it all as neat as possible….

Here is the current version of the wiring diagram, but this is subject to modification and additional fusing is needed I think on the bus-bars.

wiring plan V1ish



Engine Meets Hull

Just a note to commemorate another milestone. Yesterday we (neighbour Mike and I) lifted the engine into the boat! Hurrah!

We had spent a deal of time debating how best to do this, with the hydraulic bucket on the tractor being the initial option – but in the end we both felt a bit “windy” about working under the engine held up by an ageing tractor, and instead opted for the “trusty” Chinese chain-hoist strapped to an RSJ in the roof of Mike’s barn. We then picked the engine up, and manoeuvred the boat under the engine. To make it more interesting, we really don’t know how heavy it is – but the two of us could not lift it by hand to get it to the engine crane to put on a trailer for the trip to the barn (200yd push in light snow!)

The decision as to installation was to epoxy four M10 studs into the engine bearers and then use nuts on the studs to secure the engine bed down.

Woodwork Meets Engineering

This was another point in the build where the “looks good to the eye” world of boat-building meets the “accurate to a fraction of a mm” world of engine and transmission.  The key was that the hold-down studs were in the middle of the bearers (for maximum strength) and the engine’s “cam-belt” pulley was truly in line with the pullet on the prop-shaft.

This inevitably leads to an hour or two of “eyeing it up”, followed by a couple of goes at “marking it out” followed by that moment where one “girds ones loins”, picks up the drill and “goes for it”!

With the holes in and the studs loosely in place we tried to wrestle the engine onto its bolts while it swung on the hoist. Eventually it was done, and checked that it would all line up.

Leaving it overnight, we came back this morning, re-slung the engine to get it to better hang level, then lifted it up, removed the studs, filled the holes with neat epoxy, let that soak in and then re-filled with thickened epoxy. Then filled the drip tray, engine spacers and lowered the engine back into place, fitting the studs from above this time – some amount of fishing was needed to get all the studs properly located into their holes, but it all went together, and is now “setting” overnight.


Just a few to provide the flavour of the process…(as usual, click for a bigger pic). Boiler next!

Befur in the Barn

Befur in the Barn

alles up!

alles up!

A bit of adjustment

A bit of adjustment

Engine Installed

Engine Installed


Engine installed - view from stern

Engine installed – view from stern


Three Months and Counting!

We are feeling like the end (of the first phase) of “project Befur” is in sight – we have set a goal of having her on the water in April – the remaining 90 days appear to be passing at some speed.

This time I wanted to document the final work to get the engine and boiler ready for installation in the boat, the electrical system and Louise’s work on fitting out.

Boiler & Engine

Having completed the bench test, I disassembled the plant, making sure we dried everything out to stop the boiler corroding while in storage and ensure any frost did not cause damage. We put the sensitive bits (gauges and lubricator) in-doors to keep warm. However, a week or so later it became obvious that there was some corrosion occurring in the engine as it became very stiff to turn. So pumped some oil into the inlet, and ran it on compressed air for a few minutes to free things up and ensure everything was covered. (need to keep an eye on this over the next few weeks).

The small ball races in the scotch crank could not cope with the strain!

Also, as we cleaned up, we discovered a collection of “bits” in the sump, which revealed themselves to be the remains of a set of small ball-bearings from the “business end” of the scotch crank driving the pumps – I had worried about their small size, and testing proved this concern to be correct! (There were a lot of bits!)

I remade the crank pins in silver-steel and hardened the running part and fitted small needle-roller bearings which hopefully will survive the loads better – time will tell.

Boiler with cover, and engine ready to be lifted.

The remaining task was to make an outer housing for the boiler, to keep the hot bits at bay, and look a little nicer. So it was back to the woodwork!

In my hurry (and cheap-skate mindset) I decided to make the cover from ply with wooden cladding – and purchased a bundle of the cheapest battening from the local builder’s merchant. The first job was to get the ice and snow of this and then chop it into appropriate lengths, ready to plane to size – the planer didn’t like the ice! So the timber got put in the boiler house to dry out for a few days.

Then it was planed to size and epoxied into place on the ply, and varnished. Of course I was hurrying things too much, and the wood continued to dry out while it was in the house being varnished – so the end result has some rather “rustic” warping and splits, but given that this is not a structural component, it will have to do for now!

Following on from Lou burning herself on a hot funnel a few years back, I also decided to fit some handrails to the boiler to encourage people not to catch hold of the hot bits. I was quite pleased with these. I had purchased some bronze castings for the ends of the handrails (at and SBA auction), and nickel plated these (along with some of the valve-gear components on the engine) in the same way as previously done for other engine parts. These matched the A4 (316) stainless tube for the rails and make the finished job look quite nice. (click pic for larger version)


So while some members of the SBA are firmly of the opinion that electrics and steam boats should not ever be seen together, Befur is having a complete set for the following reasons:

  • The boiler is fired by a standard commercial pressure-jet burner which needs 240VAC to drive it.
  • The composting loo requires a small fan operating continuously to keep it running cleanly (i.e. not smelling, no flies etc.).
  • As Befur is going to spend her life in the water  (as opposed to on a trailer), we need automatic bilge pumps and navigating lights.
  • As (in the end as a sailing yacht) we aim to do some coastal sailing we are fitting her with VHF radio.
  • As we are aiming to “camp” on the boat we also need cabin lights and the ubiquitous USB charging points!

Electrical Panel

So the plan is to have batteries to drive a 240v inverter for the burner (which also provides the USB sockets), and drive the other ancillaries. When running the batteries are recharged via the alternator on the engine, but when moored solar panels on the cabin roof are designed to keep the batteries topped-up and replenish power used for anchor lights, bilge pumps and loo.

After a lot of thinking and head scratching, we eventually concluded that a 100amp-hour AGM leisure battery should provide enough capacity (remember the inverter draws about 25amps to run the burner, and it might take about 10 to 15 minutes to get steam to run the engine and steam pumps before the alternator can take over).

The burner only consumes about 300watts when running, but as the fan/pump motor is an induction one the start up currents are much higher. After trying several inverters I eventually settled on one rated at 1,500watts which seems to do the job.

As to the solar panels, it is quite hard to guess the size needed. The only continuous loads are the loo fan (which is v small ~150mA) and overnight LED anchor-light (5w). So in the end I opted for a pair of 10W semi-flexible panels.

These will be wired in parallel (to help overcome the loss of power resulting from one being shaded by a mast or rope), and we have fitted a PWM power controller. This prevents overcharging, and also has a function which provides switched power for navigation lights which automatically turns on/off at sunset and sunrise.

Testing Electrical System, although Cumbria December sun didn’t appear to be bright enough to generate a measurable charge!

These controllers are not the most efficient – MPPT controllers do a better job of extracting power from the solar panels, but cost ~£100+.  The Chinese  controller I purchased is called “MPPT T40” in an attempt to fool the purchaser, as it is actually a PWM one! – come-on eBay!

I built a control panel to hold all the switches, inverter, controller and fuses (the controller is not fitted in this pic.)

Testing 100+AMP thermal breakers is a challange – even the welder would not make the largest ones trip out before the breakers in the house decided the workshop looked like it had shorted out!!!


Lastly, we should include some pictures of Louise’s efforts in producing the first cushions for the cockpit – she has quite a lot of work ahead of her, as we also need cushions for the beds in the cabin – a cover for the boat and eventually sails when we fit the mast and sailing rig next year – they look very posh!

Louise and Cockpit Cushions




A final video: Everything running on the bench

First Fix the Bugs!

Following on from the Boiler test, and a quick trial we identified just over 20 items that needed some attention. So a week later, with all these items fixed (from leaking valves to painting and plating valve gear components), we are ready to try again.

The Fire-up Plan

We enlist the support of neighbour Micheal Slack (who is also housing the hull) and embark upon a frantic half hour of trying to put the water and steam where we need it and get the plant running properly.

This involves:

  1. Lighting the burner, and raising some steam.
  2. Getting the blue steam pump pumping cooling water thru the condenser to condense the exhaust steam from pump (and engine).
  3. Warming the engine thru with steam to get it ready to start.
  4. Getting the engine to run so that the air pump removes the condensed water from the condenser to create a vacuum.
  5. Getting the boiler feed pumps on the engine running (so Mike can stop with the hand pump).
  6. And get the alternator running to prove that we can provide electrical power for the burner, lights, radio etc.

Getting that lot to happen at the same time took some time and several attempts (and a lot of water on the floor)! It will me much easier when there is a lake providing the cooling feed water, rather than a hosepipe and bucket! But it all worked even the real McCoy lubricator and the whistle!

I was also pleased that the engine does not appear too noisy or knocking, just a bit of noise from the chains. So a good day!

A video of the day

Enjoy the video of edited highlights – with enthusiastic commentary from our “cameraman” Louise!


Worthington Simpson Pump Restoration

You will have realised that I am a bit of a sucker for ageing lumps of cast iron in need of restoration. So I could not resist a circa 1940 Worthington Simpson Steam Pump that Mark Rudell offered to me. It seemed it would serve well as a boiler feed pump or circulating pump for the condenser. (providing I could ignore the fact that it’s about 5 times the size we need – but hey the designer said I needed 500KG of ballast in the bottom of the boat, and given I can barely lift this beauty it’s all grist to that mill!)

It clearly needed a bit of a clean and a check over, and it took about a week’s work. These are often known as “Donkey Pumps” as they tend to do their work for years with little in the way of maintenance or attention – it seems this one had certainly “done its time” in this mode.

Rather than provide a blow-by-blow commentary on the work it involved, the following pictures will hopefully provide the detail:

  1. Get it apart, Inspect, remove (many) layers of old paint, and clean inside and out.
  2. Reface the mating faces of the pump valve chests.
  3. Reseat/regrind the 8 suction and supply valves (using reciprocating valve grinder).
  4. Repack and adjust the glands on steam and pump cylinders.
  5. Make new packing rings for pump cylinders (in PTFE).
  6. Turn a blind eye to the wear in the pump cylinders (I might re-sleeve these later)
  7. Paint.

It runs well, and the remaining wear in the pump cylinders make it less efficient than it should be, but in it’s planned role as circulating pump it should be fine…. The pictures show some of the steps: (remember you can click to see a full size image…off to watch Strictly !)




A Boiler Full of Steam

Well the 10th November 2017 marks a major milestone – the boiler passed its initial inspection and steam test, and is now certified for use. (big smiles all round).

Picture of Engine, Boiler Etc. ready for test

Sadly, everything was too frenetic to take pictures during the steam test – but here it is just before we pressed go!

John, our inspector from SBAS Ltd (the SBA’s Boiler Inspecting Company) had been booked to arrive at 3:00pm – at 9:00am I set about final sealing of the try-cocks on the sight gauge – at 1:30pm I nearly called to cancel the appointment as no amount of fiddling and fitting would make them seal, with a constant drip from each of them at anything above 50psi 😦

Finally I made them seal with a combination of shredded graphite string and a binding of PTFE tape to seal the valve stems – dry as a bone at test pressure of 375spi, big sigh of relief. A final tightening of some of the 60+ joints in the steam circuit and we wound up with a boiler that held over 350psi for over one and a half hours without a single pump being needed. (This is a hydraulic test so the boiler is filled to the top (to exclude all the air and thereby minimise any “bangs” resulting from a failure.)

So the pressure test is complete. Next the steam and accumulation tests. So we wheel the complete set of machinery (engine, boiler, steam pumps, battery and regulator) outside (with a lot of puffing and blowing), drained the water in the boiler down to operating level, and we light the burner.

The burner needed some adjusting to get it to light and burn fairly cleanly (a little more tweaking needed) and we quickly had 10psi on the gauge (5-6 mins)  – so we turned off the burner and checked round for leaks or other problems and to let the boiler “adjust” to its new state of hotness.

All looked good so we brought it up to 50psi to check the water gauge (sight glass) was reading correctly and all the various blowdows operated correctly – they did! (more smiles).

The next step is to make sure the safety valve opens at the correct pressure and is able to control the pressure within 10% of safe working pressure with the burner full on.

So, burner on and another 10mins to come to working pressure of 250psi (17Bar) – whereupon I got an impromptu (but complete) hot shower. The safety valve did open OK, but as the water was quite high in the boiler. and had been dosed with washing soda to bring the PH up to 11 (and probably because of all the crud left in the boiler) we got a lot of water carried over into the exhaust steam (what is known as priming) which provided the aforementioned hot shower. There was enough showering down on the 240v wiring of the burner that I decided to kill the power while we dried things off….

So with a little less than a litre of diesel left for the burner we lit it once more and went for the accumulation test. By now it’s getting a little cold and dark, so reading the gauge within the billowing clouds of steam was quite hard for John, but after a few minutes he was happy that all was good – we were passed.

Not wanting to waste all this nice steam we tried the Worthington Simpson steam pump (A post on the restoration of this is on the way) in anger, and it performed quite well – supplying feed water at over 200psi….. and then we tried the engine!  after some warming thru this ran too and even the generator seemed to be making 7.5amps at a modest speed – but we highlighted the next (somewhat expected) list of jobs:

  • Two of the relief-drain valves seemed not to want to close (more clouds of steam and investigation needed)
  • The circulating pumps (engine driven) did not deliver enough cold water to the condenser to condense the exhaust steam and create the vacuum. So we are going to revert to the original design of the engine-driven pumps acting boiler feed pumps and the steam pump as a circulating pump.
  • I think I saw a couple pin-hole leaks in the feed pump plumbing which need checking
  • We need to finalise the plumbing from the cylinder drains
  • On the next run we need to get the displacement lubricator running.
  • We need to check the alternator performance to make sure we can generate the 20+amps we need to drive the inverter for the burner.

….then we can think about attempting to install the whole she-bang in the hull!!!! (Spring ’18 Launch – yes,  I think we might make it!)


A Plumber’s Nightmare & a Real McCoy

Over the last few days we have encountered the two items mentioned in the title in real life, in a slightly stressful way.

The Real McCoy

One of Elijah McCoy's displacement lubricators - actually this one was made by the Detroit Lubricator Company.

One of Elijah McCoy’s displacement lubricators – actually this one was made by the Detroit Lubricator Company.

While Wikipedia suggests two origins for the phrase “The Real McCoy”, the most well documented version relates to one of the brass beauties shown here.

It is a displacement lubricator patented by one of Elijah McCoy’ in the 1870s in America.  These devices perform a simple, but vital, role of providing internal lubrication for steam engine cylinders and valve gear, but they do it using an apparently impossible process.

Basically they are attached to a ‘T’ in the steam line supplying the engine. You fill the lubricator with oil, and then via a mechanism which is not at all intuitive, the steam in the steam line to the engine decides it would prefer to be in the lubricator and, as it migrates that way and condenses as it cools, displaces the oil which is forced back into the steam line. So the connection to the engine sees steam heading one way and oil heading the other with nothing obvious causing that to happen!! The lubricator has a number of valves to control the rate that this happens and allow the machine to be shut off and refilled while underway.

Apparently Elijah McCoy’s  lubricators were so good and reliable that companies wishing to purchase steam locomotives were given to checking that it was fitted with a “Real McCoy Lubricator” – hence the phrase 🙂

In my case I purchased this at an auction a few years ago, and prior to fitting it I needed to pressure test this (as with all other pressurised components). As I did this, it revealed a number of leaks and failed seals on the two sight glasses.

Taking it apart revealed seals that may once have been rubber, but in the intervening years (100+?) had turned into something more like wood. I managed to find some replacement ones that just needed shortening, but fitting these is a tense process as cracking the glass would be just too easy.

Anyway, we managed it, and with a little TLC and returning some of the needle valves, we had the Real McCoy: a leak-less displacement lubricator.

The Plumber’s Nightmare

The fwd boiler fittings almost complete.

The fwd boiler fittings almost complete.

The rest of the week has been consumed by attempting to fit the fittings to the forward end of the boiler.

This seemed as though it would be a simple process, but pushed me to the edge of serious depression.

Due to the temperature and pressure of this assembly (250psi and 200+ degrees Centigrade) all of this needs to be in steel pipe with screwed fittings.

The problem is that while one can imagine how it all goes together, the reality is more complex, principally because you can’t actually screw all the parts together as the end points are fixed and so you can’t tighten everything.

Moreover it appears to need a certain sort of brain/thinking to figure this out – my respect for plumbers has been raised considerably! This was born out by half an hour in Penrith at the sales desk of a pipeline and hydraulic supplier while the staff demonstrated considerable fortitude (and difficulty) in “rummaging” through their stock to find the combination of bits we needed. (Actually I found this quite encouraging – if they couldn’t sort it out, perhaps I was not being a complete klutz.)

The net of this story is that what you need are “cone unions” – and I think the ones provided by Bessegers (like these) are by far the best design. These allow you to assemble the screwed bits, and then attach the assembly to the component you are plumbing without needing to move the joints you have made.

The second take away, is that sometimes you need to opt for an indirect path for the piping to allow you to accommodate the offsets in all three dimensions.