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[around]

In 1985 I started the construction of a live steam tug based on a Kingston Moulding 35" TID Class tug.  I decided to build a Stuart D10 with reversing gear and feed pump as the power plant.  A busy at-sea career in the Navy and the addition of three young children saw the project stalled with the D10 constructed and two deck stringers installed in hull.

With children now in University and time at sea a thing of the past, I have recently dusted the hull and engine off and recommenced the project.   Having the benefit of all the web-based hobby forums to now draw on, I can see that the D10 is probably a bit on the large side for a 35” hull but making everything fit will be part of the fun.

I have mounted the engine, installed the shaft line and constructed the propeller skeg and rudder.  I flashed up my CAD program and drafted up a universal joint to deal with the height difference from the scale shaft location and the flywheel of the D10.  Machining it out of steel seemed better than the plastic offerings at the local hobby store.

As the tug will be RC, I then designed and machined a rotary regulator to allow servo control of the steam supply.  The D10 reversing gear was easily adapted to accept a control arm.  A displacement lubricator was the next machining project (shamelessly copied from a picture in my old Stuart Turner catalogue).

I have now drafted out a 3D model of the boiler based on a design in Martin Evans Model Locomotive and Marine Boilers.  I will be fitting an exhaust feed feedwater heater and an economizer to the feedwater loop to maximize the steaming capacity of the boiler.  The feedwater will be automatically controlled.  I intend on modifying Malcom Beak’s automatic boiler level control system.  I will update the electronics to use a small microcontroller and all surface mount components.  My plan is to fire the boiler with gas using a steam pressure attenuator based on the Christopher Leggo design.

I find a lot of my time is now spent pondering on how to ensure that everything:

a.   Fits in the hull:
b.   Does not interfere with the superstructure/deck; and
c.   Perhaps most importantly, can be removed for modification and servicing.

I have attached a few pictures of the progress to date and will update as things develop.


Cheers,

Adrian

[HS93 (RIP)]

Thats very nice and welcome to the ever growing steam members on the forum. have you tried a displacement test yet ? I am building a HS tug from the same company and was surprised when I did a test, should I say we went on a diet and the water tanks where cut down a bit.

Peter

[around]

Peter,

She has been in the bathtub with the engine installed, all the boiler components (in their 'raw" state) sitting in the bilge and a full one liter plastic water bottle.  My sense is that I am still going to need ballast to bring her down to the scale waterline.   I do not see having a lot of empty space in the hull so I may have to get creative with some moulds to squeeze the lead in!

Cheers,

Adrian

[HS93 (RIP)]

some people use lead shot in bags when they get the weight right they put some resin/epoxy in it you can then remove it at a later date if you need to move things about.

I wish I was in the same position as you over weight.

peter

[around]

Here is the 3D model of the boiler with the shell and funnel removed.  I am planning of using A BIX 008 burner which is shown in black.  I have a small steam dome, fed through a number of small holes under to dome to reduce the chance of priming.  Pressure guage and main stop attached to dome.  Safety valve doubles as the filling plug.  Water guage and feedwater check valve on the burner end of the boiler. 

"Superheater" and economizer loops not yet shown.

I plan on having the burner end of the boiler forward as this makes it easier to get the funnel in the scale postion.

Cheers,

Adrian

[derekwarner]

Adrian...sometimes for the sake of redundancy & safety....& I understand that your proposed boiler filler plug /relief valve will have static o-ring sealing.........however it may be preferable to seat & seal the relief valve ....test the integrity for steam tightness then leave it!

An additional boiler bushing for a dedicated water filling tapping port would have advantages ...... ....Derek

[around]

Derek,

Thanks for the recommendation.  The safety valve that I currently have is the large 60 psi Stuart Turner valve.  In my Stuart Turner catalogue (circa 1991) they suggest using the safety valve as the boiler filling plug and then using a soft aluminum washer to ensure a steam tight seal with the boiler ferrule.

Can anyone shed any light on using the Stuart Turner safety valve in this manner?

Cheers,

Adrian

[derekwarner]

Adrian......more recent designs ..say 1995 to current by the steam modeling fraternity prefer O-ring soft sealing similar to JIC or UN-O ring format as used in industrial hydraulic applications

I understand this is fine for vertical porting arangements ....but for 90 degree alignments poses problems.......

Whist I was supplied with numerous 1/4" ID thickness copper washers to enable the desired alignment....the concept is flawed so chose one only copper washer....then lapped the boiler bushing until a 5 degree radial compression was evident.........installed the valve with Loctite Super HT sealant & rotated the last 5 degrees ........Derek

[kno3]

Nice work there Adrian!
Regarding ballast: I've found out that lead sheet is much more convenient than lead shot. You can shape it to the bottom of the hull and there's no need to glue it in place, which helps if you add things later on and need to remove some ballast.

[HS93 (RIP)]

Nice work there Adrian!
Regarding ballast: I've found out that lead sheet is much more convenient than lead shot. You can shape it to the bottom of the hull and there's no need to glue it in place, which helps if you add things later on and need to remove some ballast.

if you read the post you would see I said leave it in the bag so it can be removed.

peter

[kno3]

It is still more convenient and space-saving with sheet lead, I tried both 

[gondolier88]

Bags split- nuff said!!!!!! I prefer sheet too.

Greg

[Underpressure]

Ballasting the Muimota recently, I have used bagged lead shot, old airgun pellets, also in bags, lead sheeting rolled into blocks and tins of unused airgun pellets. The bags stay in place and everything else is removed for transportation, as this keeps the boat ballanced, but means I don't have to try and pick up a 48lb (22Kgs) boat  

I like lead shot in the stern, especially with tugs that have a long shallow stern. I put in a few bulkheads and just fill them up, I then either epoxy and bag the shot, once the weight is correct, or alternatively I leave it loose, but close in the bulkhead with a false deck, to prevent the shot from escaping.

There is only one thing worse than trying to put a bow heavy boat into a car, and that's trying to get it out    

Nice work Adrian, much better than anything I could make.

Care to share the design of that steam valve with us...pleeeese.

Neil

[around]

Neil,

I would be happy to supply you with the drawings or the CAD files for the steam valve.   It is a modification of a hand drawn plan I found on a free steam plan site.  There was no name attached to the drawings so I cannot give credit where credit is due!

Drawings - I usually format the drawing to show decimal inches (e.g 0.188) as my mill has a DRO and I use the DRO rather than marking everything out.  I can also format them in metric or fractional inches.  Let me know what works for you.  They would be a PDF file.

CAD files - I am lucky in that I have access to Autocad Inventor through my work.  I can supply the Inventor files or convert them to other formats if you have a CAD package.

Let me know what your preferences are.

Cheers,

Adrian

[Underpressure]

Thanks Adrian,
                    Metric or fractional inches are both fine with me, I'm of that age group that can happily work in either.

I'll PM you my e-mail address.

Neil

[around]

Started to work on the boiler this weekend.

Squared off the ends of the boiler shell, clamped it in the mill and drilled all the various holes.  Then chamfered the internal edge at both ends to give a nicer fillet for the silver solder.

Then it was on to making the end caps.  After machining the required former and backplate out of 1" oak, the copper disks were cut out on the bandsaw and the fun began.  I took six cycles of annealing, clamping on the former, "persuading" with a hard plastic hammer and then re-annealing to get the flanges looking reasonable.  The endcaps were then mounted in the lathe and machined to the correct length and diameter.

The water tubes were cut to size and annealed in preparation for bending.  As you can see from the attached drawing, I need to bend a couple of different radii in each water tube.  My task for the next day or so is to build a suitable jig to ensure that I get a consistent shape for each tube.  There are 17 in total (10 ft of 1/4 tube) so it is worth spending the time to build the jig.

Cheers,

Adrian