Small steam tug

[PeteThePen1]

Hi

Great to see your progress. For the rudder, why not mount a pair of them on the transom either side of the drive shaft? In my head siling dinghy technology would be fine. Just a couple of 'pins' screwed to the transom for each rudder and then the rudders themselves can just lift off for towing etc. Taking the dinghy tecnology further and having a rudder blade held down by 'elastic' could be useful in shallow waters.

Sorry to hear that you still have frost over night. Here in Cymru we have had a long run of dry, sunny days and warmish nights. Yesterday reached 20C during the day with today forecast to be higher. Watering one's garden plants in March is not what I would have expected to do. Must be that phenomenon that the US President does not believe in.

Looking forward to the next installment.

Regards

Pete

[rolphill]

I did some things. I've been working on a bigger lamont boiler but I had to pause to do family summer stuff and during the break I got the itch for boating again. So I've been working on the little boiler and the outboard.

I want to make a small modification to it, which is automatic water level maintaining. I pulled the top cover off so I could drill a hole for the water probe. I might also remove a bit of superheater while I'm in there. Yes, remove superheater, as I'm pretty sure the last steam up did some damage to the o-rings. The engine has a bit less friction, but doesn't pull as much vacuum when turned over by hand as it used to. Also the cotton insulation on the first foot of steam pipe out of the superheater burned off.

IMG_2073.jpg (189.26 KiB) Viewed 43104 times

IMG_2076.jpg (186.18 KiB) Viewed 43104 times

IMG_2075.jpg (63.09 KiB) Viewed 43104 times

It's nice being able to just open up the whole boiler and look inside. Note that the rust is particles on the walls from well water, not eating into the walls, which are zinc plated.

I also threw together a simple controller using scrap parts. It only uses three transistors, no arduinos or anything. It also has an off delay of a few seconds to reduce short-cycling of the water pump.

[rolphill]

We finally did it! A new steam boat enters the world!



The boat is registered, I got everything I needed, and the engine is ready. Note the 70 year old 2stroke outboard in the background that already left me stranded in the water, it's days are numbered.

First thing's first, I did the new boater thing. (forgot to put the plug in). After fixing that, I left the boat ramp with the trolling motor. There wasn't any traffic, but there was a big algae bloom I didn't want in the boiler.


The trip was almost cut short after a frustrating few minutes trying to light the firestarters with matches.


But we eventually got the fire started, the gauge needle lifted, and the engine warmed up. Time to give it the beans! Well, like two and a half beans.





Success! After putting around in circles for an hour or so, I motored back to the ramp under power of steam.

Post water inspection. The outboard survived. The upholstery on my old beach chair did not.

The day was a total success, everything worked (almost) flawlessly!


Post game analysis, starting with the good:


Nothing broke, the boiler boiled, and the engine ran. It was very torquey, you can see the whole boat move every time it rotated.


Having ball bearings on almost everything on the engine was nice, as I didn't have to worry about oiling everything, just one squirt on the eccentric. The o-rings held up just fine too.


The boiler electrode, water level controller, and water pump worked flawlessly*. I never lost prime, and the intake tubing on the outboard stem seems like a good spot for it.


The boiler didn't seem to mind the lake water, there wasn't any excess foaming except when blowing the whistle.


Maintaining a strong fire was an every minute job, but not difficult with wood pellets. Every minute or so I pushed the pellets in the doorway down into the firebox, and made a new doorway pile with 2-3 scoops.


The outboard gearbox and propeller didn't break.


Now the bad:


I need a rudder! Without it the boat slowly goes in circles, and using an oar to keep straight sucks.


The boiler is too small! I was seriously over firing this little thing, with stack temps of 700-800f. Even with this, the boiler was never able to sustain anything above 60psi. Even so, I only went through one gallon of wood pellets in an hour. I only managed about 3mph max.


My engine timing is terrible in this direction. I really wasn't able to notch up at all going forward, while I could smoothly adjust the cutoff in the reverse direction. Instead of trying to figure that out, I'm just going to get props that spin the other way. After all, it is a hackworth.


The water pump has a built in pressure switch for RV use, and I forgot to screw the adjustment all the way in on this one. So it didn't want to kick on above 60psi or so. However the hand pump was plenty, and I fixed this as soon as I got home. Otherwise it maintained a perfect water level without short cycling.


The outboard mounting clamps are garbage. You can see the whole engine rock every time it spun. I'll have to fab something much sturdier up. I might add a block lower on the outboard stem to help distribute the forces.


The steam line from the boiler to the engine needs to be secured in place. It was constantly swinging, and that's gonna fatigue it out.


I need a removable mounting system for the boiler. I just screwed it to the bench with wood screws for this run, which is bad. I also want to put it on the rear bench if keeping the fire up isn't too inconvenient there.


I might want a lower pitch propeller on it. This was an 11x7 APC prop, and I don't think the engine was able to spin fast enough to shorten the cutoff. I'll try a 5 pitch next time.


I need bigger water filters. I had two little ones in parallel, but the pleats immediately crushed a little bit. The water pump has a fairly high flow rate.


Oh, I also need to route the exhaust line better. It's currently hilarious.