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[xrad]

Hello All,  Been a while since last post. Built many model projects and wrote many C++ model codes in the last few years. But now, I am am working on a new 1/24 scale Brooklyn tug based on original blueprints from Camden NJ USA shipyard(my home county!).  It will have either a mildura or Stewart marine twin and a home made scott boiler....should be a cool project. I built one of the 1/32 scale dumas tugs in live steam a few years ago and it is tied with my lightship models as a favorite subject.  Here is a pic of hull plans. 52.5" stem to stern length, 12.5 width (may have to adjust a bit for seaworthiness)

[Capt Podge]

This looks like an interesting project. I have no experience of steam models but I'm happy to tag along and see how it develops.


Regards,
Ray.

[derekwarner]

I remember your 1:32 scale version from 2014/5/6 very well 


https://www.modelboatmayhem.co.uk/forum/index.php/topic,48955.msg502623.html#msg502623


So will look forward to this steam build


Derek

[Mark T]

Welcome back xrad - about time too     I'll be watching this one mate 

[carlfmiller]

Oooohh-- I wanna see them planks go on. i had no idea how to plank a tug, so I made it up, and used this unorthodox method, using all straight 1/8 x 1/4 cedar sticks --no steaming, no tapering. The keel was installed after the hull was made, and curvy part next to the keel was made with epoxy filler WEST 410.


It will be fun to watch you do it--probably the "right way"; the lines are similar to St Andrew






-Carl

[Jerry C]

I was a particular fan of “Moran” tugs in the States during my travels.


Jerry C.

[xrad]

Hi everyone! Thx for replies! I don't know if there is a 'right way,' whatever works is always fine.  yes, I have missed boat building...forgot how much fun it is!  So the hull frames and stringers in rough orientation. Hull will be glassed so not too concerned about minor details at this point....I added 3/4" of freeboard to make here a bit more seaworthy...

[xrad]

rough wood planking..looks don't matter here.  Then a wipe of bondo fiberglass resin over the planks, which makes a better coating for the 5 oz cloth.  Then lay on the glass. Then coat with more resin.  When resin dry, a light sanding. Then thick coat of woodland scenics modelling putty(it's like spreading cool whip..and it's the cheapest of the light model pastes..). woodlands putty is light and very easy to sand. great for building up the hull where needed. great for filling gaps. 

after dried and faired, then the real hull build begins...Not sure if I will make a split mold or just glass inside-out a one off....

[KNO3]

I'd like to see how you make the mold.

[xrad]

I decided to make a one-off.  Short answer: But if you were to make a mold, you would need to make a perfect hull 'plug' with any detail like rub rails built in.  then put a 'seem' divider down the middle (a doubled thin piece of ply or similar bolted together- not glued). then wax and lay up a gelcoat, then strong glass mat.  Do one side at a time thereby making two halves.  Pop these halves off, polish inside and wax. Then re-bolt halves together. Now you have a female mold master from which you can make the model. 


this is helpful:
https://www.nordictugs.com/nordic-tug-factory-tour/

[RST]

Pretty sure that filler from Woodland Scenics might be the same as deluxe materials and a few others. You might find it way cheaper to use DIY stuff from Screwfix or BnQ for exactly the same product. Pollyfilla make no discernable different product if I remember. I guess the equivalent for you would be Home Depot. I know I've found the same stuff here anyway and also in Castorama in France for 1/10'th the price for the same thing for bricolage (though France naturally more expensive).

[carlfmiller]

So what will you do to make a one-off? I guess the hull you are making will still be a plug, and that you will glass over it in several layers/directions, then maybe vacuum bag? I guess you cannot pull a vacuum with the hull still on bulkheads. So you lay glass and then more resin then have a sanding and fairing party to get it smooth?I hope you will share the process. Sounds a lot easier than making a mold, then vacuum bagging a hull on the mold. I'd like to see the glass thickness as you make the lay-up. I've never done this.


-Carl

[xrad]

Thx for replies and tips!  yes, the light filler is a bit pricey, but i only needed 3.5 jars at 11$ each.  Yes, one off hull. plenty of sanding and fairing to do.  I use bondo to smooth the hull after a few layers of 5-6oz cloth. It's supposed to represent a metal hull so a few imperfections (aka 'dents') actually add to the realism. I will post pics as build progresses...but mixed up in several other builds as well which delay this whole process....

Received my copper 'L' pipe (seamless tube) today for boiler. 4" horizontal cross tube design using 1.5" flue with 3/8 cross tubes, all 'L' thickness. These are 1 ft sections which will be cut down as needed. Have to calculate the measurements, but should provide enough volume and steam for the mildura...probably a machined bronze steam 'dome' if i'm lazy, or a copper riveted dome (yet to be decided).... I have used 'L' on my other boiler builds and it is plenty thick for this size boiler...


For cutting some of the copper sheet for boiler ends, I plan to try my plasma cutter...will see how that works out!

[xrad]

bondo.....

[KBIO]

Hi !
That's going to be an interesting project !


I plan to try my plasma cutter...will see how that works out!
[/size]This will be nice to see and learn.
[/size]Regards.

[xrad]

Some more work on the 1/24 tug build.  Cutting inexpensive copper water bottle to make water tanks. Replacing long crank with short crank on Mildura Marine twin. Basic setup in hull.

[xrad]

I wrote some code for a water level sensor and steam pump valve control unit as well as for a condenser tank pump controller. The boiler water level sensor is a two wire circuit, one contact inside the boiler, and one on outside. It is very sensitive so I may need to add a sensor 'averaging of reads' or 'delay' to the loop. The boiler controller has a USB charger/internal battery and can run by itself. Or you can hook it up to the condenser pump controller and a larger battery.  If you want to prime the boiler pump, there is a 5 second auto-run button. Just keep pressing it until pump primed. Then you can adjust the 'fill' run time with the rotary encoder.  see the build here, including the C++ code in case you want to make one:


https://forums.adafruit.com/viewtopic.php?t=191380


The condenser tank pump is just a motor speed controller which operates via a push button.

[SailorGreg]

Welcome back! What's a couple of years between friends? 

Looking like a comprehensive suite of controls you are fitting to the steam plant.  The boiler looks lovely, you have done a great job there.  It looks like the hull is much as it was 2 years ago but it never pays to rush these things!

Greg

[derekwarner]

You got it ...welcome back xrad .........regards Derek

[xrad]

Thanks Guys! I appreciate your return welcome!    I missed this forum but I was busy rebuilding a few cars, and creating many electronic projects.  Too many hobbies, not enough lives...lol...Thought I would get back to this build finally as I have a few weeks off.   Yep, hull unchanged .  But will be soon! More to come.....

[xrad]

I machined up a fitting for the boiler sensor. It is brass, stainless, and has some 3/16 Teflon rod. I drilled the rod in reverse on the lathe, using a 2mm drill. 2mm threaded rod through the teflon.  The brass fitting is drilled two sizes, a hair under 3/16 for the teflon rod (but not all the way through). then a slightly smaller size so that the pressure does not blow the teflon out.  I machined a tiny teflon bushing so the rod does not ground out on the brass fitting (not pictured).  The first attempt with the short teflon rod did not work as boiler bubbles coated the short rod enough so that the circuit never showed discontinuity.


the second attempt used a longer teflon rod and worked fine.  The sensor detects low water between the two black marks on the sight glass. when the boiler gets to the bottom mark, the senor is always triggering.  Now it's just a matter of finding the correct 'fill time' which is adjustable.  I don't want to fill too much and lose heat, or too little and then always cycling.  Will depend on water pump output also......

[xrad]

So I cut the teflon tube in half (from the long tube pic above). This sensor now works perfectly.  I have two marks on the sight glass, high and low. The sensor trips at the low mark. I hooked up my double slide valve pump.  I timed the water pump valve by hand to the servo motion.  You can see the marks on the water bottle. I sloshed around the water in the boiler without false triggering. With the sensor in the center of the boiler and dropping in from the top, it is in the best location to avoid false triggering from wave motion. 

I had the timer set originally to 5 sec, but moved this to 6 sec after several runs. the boiler fills each time to the high mark! Nice!  Since the amount of 'cold' water is relatively minimal, the boiler maintains pressure and temp fairly well. and the pump is not cycling at all. 

If on the water, the boiler begins to overfill due to false triggering, I will write some more code to diminish the false signals or delay another fill cycle.

[xrad]

mock-up of the boiler gas control valve and fresh water tanks:

[xrad]

condenser bungs machined up. water tank endplates formed.

[xrad]

finished the condenser. The condenser is dual purpose. It preheats the boiler water and condenses the exhaust steam.  The boiler preheater fittings are made with 5/16 brass pipe (the thick walled stuff for live steam). 1.5" lengths pressed into 1/2 bronze bungs I machined off 1/2 bronze rod. Then, pipe threaded 5/16 x 32 UNEF. I had to split the die and spread it a little with the grub screw for correct thread diameter.  The fittings are then soldered to the end cap.  A copper coil is made from inexpensive refrigeration tube (.18-.19" dia..i forget the fraction..probably 3/16th).  Then the coil is brazed to the fittings and end cap brazed to the condenser body.  All parts brazed with 45 silver solder.