A Smaller Steam Engine For A Smaller Boat

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I came up with a mount for the boiler. I went with wood so it wouldn't become a heat sink. It holds the boiler just a little above the drip pan for the same reason.

Not sure where to go now. I may get the engine plumbed in and run it to see how fast it uses water. That would give me an idea on how much H2O I need to carry, so I can build water tanks. If I do that I need a water gauge on the boiler.

Pete

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Pete,

Keep things simple.

From my own and many other peoples' experiences, unless you are doing a 24 hour marathon, look to have a run of around 20 minutes.

Some people try to put all sorts of junk on their steam plants, and most never get to use those expensive bits, gas attenuator valves, auto water top up either electric or mechanical, water tanks etc etc, especially if you will be using a displacement lubricator. All they are are show off bits for people with more money than sense. Some people have it all controlled by a computer, they may as well fit an electric motor as propulsion and a smoke unit to simulate steam.

After 15 to 20 minutes good sailing, you will be ready for a break and to top up the lubricator and give the engine a bit of a breather and a drop of oil on the outside.

John
 
I agree completely. I dont want to run longer than that because something always seems to need attention by then.
That is one of the big driving forces on this boat is ' simple ' My big sternwheeler is not even close to simple, and today proved it. I hauled it out to the pond which is no easy task. The engine driven water pump wasnt hooked up ( forgot after the last cleanup session ) so I kept having water level problems till I finally figured out what I screwed up. Since everything is hidden by the superstructure spotting problems is tough. Next was one of the burners was turned up too high which temporarily warped the outer shell of the boiler box enough that the access door to light the burner opened while on the pond underway. Well that set up a small blowtorch that cooked a bit of the boat and actually lowered my steam pressure. While on the water waiting for pressure to build one of the cylinders filled with water and locked the system up. I finally tried opening the cylinder drains and off she went. Needless to say it was a bit of a frustrating day, but still good day since I was on the water under steam. I am looking forward to an easy access, easy lift boat. Now my big boat has a bit more realistic look since its has had a bit of a fire :D
Pete
 
On the quest to test the water consumption of my engine system I am getting the boiler ready. The water level glass is next up. I used a standard 90 degree 1/8 npt male to 1/4 compression fitting for the lower fitting. My borosilicate tube is 6mm when I put a viton o-ring on the glass and cut down the compression nut it holds well and doesn't leak. The upper fitting had to be something else because I can't thread the fitting in and insert the glass at the same time. I poked around the internet for awhile and ended up going with a banjo fitting. That allows the glass to be sandwiched between the two fittings and then secure the banjo bolt.

I started with the banjo part. I matched the size of the boiler bushing diameter. I cut a commercial compression union into two parts. I cut a flat spot on the banjo to match the position of the lower fitting. Next I silver soldered the two together and drilled the hole thru the fitting. The bolt was fairly straightforward, I just had to fiddle with the depth of cutting the NPT threads till the bolt snugged up the banjo well. I wish I had hex stock to skip cutting the flats for the head. I am going to try some form of gasket to seal it all up first. If that doesn't work I'll do a little cutting to accommodate o-rings at each end.
Pete
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I mounted up the water level gauge and fired up the boiler with a temporary hookup for the engine to see roughly how much water this system is going to use. The run went fine and here is a video - [ame]https://www.youtube.com/watch?v=d4dW7hffTxg[/ame]
Next item to make is the displacement lubricator. I put fins on this one to try to cool the steam in the lubricator a little bit and it looked nice. I didnt put a drain in this one just to make it simpler, I just plan on sucking out the water and oil with a syringe. I soldered it into the feed pipe just before the engine selector valve. I put a superheater ( or dryer with this low heat ) at the top of the boiler under the funnel. I used my home made ring roller to make the spiral shape. On my sternwheeler the superheater I put on it made a big difference in performance but it is about 6ft of tubing coiled right above the burners and the copper glows over the propane flames. That steam gets so hot it melted all the hard solder joints in the supply lines several feet downstream of the boiler. They all had to be re-soldered with 45% silver to hold together. This one wont be that effective but it should help dry out the steam. Now I have to get some brass sheet to make the water tanks and condensation/oil trap tank. To get 15 to 20min of run time I will need a little more water than the boiler can carry. It used all it had in about 8 - 10 min and that seems a little short and it also meant getting the boiler pretty low on water which I dont want to do.
Pete
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I have found that working with thin brass sheet is a pleasure. It cuts easy bends nice and hard soldering the stuff together is not hard at all. I haven't ever tried to build something like the water tanks I need on this boat. I don't have a lot of space so I went with a sort of saddle tank setup. The two tanks will be connected with a pipe that should act as a manifold to supply water to the pump that doesn't exist yet. I cut a few bits of cardboard to get an idea of what they would look like. Without being real precise I called the template good and started cutting metal. A few bends and I had a good shaped tank. I soldered it up and then went to fit it in the hull and what do you know.....it didn't fit!! Not sure how I missed it but the cylinders of the engine were in the way. I guess the engine wasn't bolted down so it was free to move out of the way and I didn't catch the movement. Needless to say I didn't want to start over so I cut a relief into the tank to clear the engine. I put a fill port on that is the same setup as the oiler. I just have to make sure not to get the caps mixed up. Oil in the boiler water is a no no. I have to make one more still but I am happy with this one. I'm not sure if I will leave it as is or paint it.
Pete
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So one tank on one side looks out of balance and that means I need a second tank and the plumbing to connect them.
The second tank ( port side I think ) will just have a vent stack. I ran a copper tube from one tank to the other and then tee'd off of that line to feed the future pump. My leak checks showed me of a potential problem. The line connecting the tanks is just a 3/16 pipe, it is really slow transferring water from the starboard tank to the port tank during filling. Really that will just require a bit of patience on my part, but I wondered if the two tanks will drain evenly as the pump pulls water from them. It might be fine seeing as it should take 15 min to use the tanks water supply. That's quite a while so I'll just keep what I have and modify it later if it proves troublesome. I also added water level sight tubes on both tanks to see what they are doing and maybe be able to spot the level as it chugs past me on the pond.
Pete
 
Work continues, but slowly. I need a condensation/oil trap on the boat. In the tub I found this little boat is sensitive to right and left balance. I don't want the boat to lean more and more as it runs so I went with something on the centerline. I want it close to the engine exhaust which put it over the driveshaft. Last requirement was as low a CG as possible so the tank wraps around the shaft. This was a little tedious to build but it looks like it will work. I'm hoping that dumping the exhaust at the center of the tank will fill it up reasonably evenly. I have started plumbing it in but there will be a long pause due to a upcoming vacation.

Anyone know of steam engine stuff to see in Italy 🇮🇹 ? I might be able to talk my wife into a side trip while we are over there.

Pete
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Pete,

Not nitpicking at all but just a safety question.

Are ALL you boiler fittings made of brass or bronze.

The reason I ask is because many years ago (about 20) I purchased a very well known copper boiler and engine combination. I was in hospital at the time and to pass the long time I was in there, they allowed me to use the visitors lounge to make a model steam boat, but I wasn't allowed to bring my lathe and mill in there to make the bits for the engine.

To cut a long story short, after about 5 years sailing, I had a boiler fitting blow out.

It turned out that they had used brass for the boiler fittings, and they had de-zinced and basically the threads disappeared into a mass of 'dust'.

All I could do was to do massive surgery on the boiler and replace everything that was brass with bronze, and that boiler, even this old now, could be used tomorrow in complete safety.I used that boiler without any further trouble for at least another 10 years.

There are brasses that you can use that resist de-zincifying, but it is a bit hard to find.

No problems if you have used bronze for everything connected to the boiler.


John


http://www.model-engineer.co.uk/forums/postings.asp?th=52890
 
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I'm glad your looking out for me. Getting hurt is not a fun part of life !!
The boiler itself is all copper silver soldered with 45% silver ( not cheap ) that is bushed with 544 high strength bearing bronze from here https://www.mcmaster.com/#standard-bronze-alloy-rods/=17csg4w
After the bushings I went brass for the rest of the system. From what I have read that should be safe correct ?
Pete
 
Hi Pete,

It is a debatable issue, some people think it is safe to use brass for fittings above the boiler waterline, safety vlaves, filler caps, steam take offs etc, and others think that everything connected to the boiler should be bronze. I went the way of least argument and fitted everything in bronze.

It is assumed the problem is a combination of galvanic action (two dissimilar metals, or sometimes three if copper crush washers are used) and the dezincification of any brass components.

We are a bit of a nanny state here in the UK when it comes to model steam boiler regulations, especially if you make your own boilers. They suggest having the boiler inspected by a 'qualified' person at each major stage of assembly, so even the insides get a good going over before it is permanently hidden, and only certified materials are used, especially the outer and inner tubes and end plates, plus boiler bushes.
But on the other hand, as far as I know, up until recently, for small boilers they don't require this checking if they use the 3 bar/litre rule, so if you have a boiler that is only 1/2 litre capacity, it can have a maximum working pressure of 6 bar (approx 85 - 90 psi), or a 1 litre boiler can only have a maximum working pressure of 3 bar (approx 45 psi).

All this varies from country to country or even state to state, so to keep within the law, that needs to be checked on.

I won't go into the insurance cover thing with running these small steam engines, and not only steam, all model engines when run in public, as I am sure some members would be offended by the rules and regulations that are required.

The choice is purely yours, I was just trying to bring certain things to the attention of not only yourself Pete, but other people as well.


John
 
Thanks for the update F.

From the looks of those rules, it seems that the elfin safety brigade have managed to get home shop steam builders eradicated unless you belong to an engineering club who have boiler testing facilities.

If it was left to those Victorian thinking people who come up with all these rules and regulations, we will soon be needing annual inspection of all our machines and tooling to make sure no one cuts a finger. There will be no room for movement and free thinking soon. I can't wait to get my shop eventually moved to another country.

Looks like my boilers are all destined for the bin then.

John
 
The safety weenies are running the show. Where I work has a safety department that is growing fast. It used to be just steel toe boots but the introduction of the yellow vest was the beginning of the end. Now there are bump caps, cut resistant gloves, safety glasses and ear muffs. Rumor has it they were spotted weighing tool boxes to see if we are lifting too much......it's nuts. Personal responsibility for hurting yourself and learning from it are out the window. Now there is paperwork to tell me a razor blade is sharp !!!!!

At least my boats are just for me and there are no people around that have any idea how it even works let alone tell me it needs an annual inspection or some other insurance/ litigation driven rule. Cell phones help too, some of the folks around never see the boat, they are updating their Facebook status 😀
 
Ah yes OH&S what a joke. had to use two people to lift a tire on a 4X4 because it weighed more than 15 Kgs. Don't forget the paper cuts or eye strain that you could get while reading all the safety paperwork.:)

Cheers
Andrew
 
Oh the safety weenies do indeed run the show a few years past I had to do a two week safety induction for a nuclear power stations so I could go into the canteen to fix a coffee machine then shortly after that did a petro chem course to fix coffee machines in garage forecourts . After 40 plus years working in engineering Iv given up and hung my safety boots up thats unless Im in the shop:) you understand
One thing for certain is that I will always make and sail toy steam boats and hot air engines that is until my toes curl up or they lock me up
I can fully understand for the need for some form of regulations as they are pressure vessels but the world seems to have gone a wee bit crazy at least they seem to have overlooked the good old mono tube boilers for now
Sorry for been a bit of topic and wish you good luck with youre build
kind regards
frazer
 
when bending 1/8 inch end caps did you allow for a radius on the cap ? if so how much under size where the wooden plates used for the bend form ?
 
mrputz1 - Are you asking about the end caps of my boiler ?
Pete
 
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