"Inspired" by gas prices...

[tugboat]

Originally Posted by Dave T

Tugboat I'm glad to see that somebody with more knowledge on steam boilers than me is interested. I am re-thinking my idea of maybe building a firetube instead. I am thinking of using a piece of 8" bore hydraulic tubing from a scrap cylinder I can get free or little cost at our local junkyard this should be way overkill to withstand the pressure . What size and wall thickness tube would you suggest and how many for the firetubes. Are you currently using steam power? What I meant by steam engines being too expensive to be really practical I was thinking for the average person if they had to buy an engine and boiler you could still bye a lot of gasoline for what they cost. Keep us informed of your progress and good luck. I do believe their is a future for steam power if some one can reduce the initial cost or we run out of oil.

Dave T

Hi Dave--yea thats what i did--went to a local scrapyard and found pressure pipe there--i have a chunk of 1/2 inch thick 30" pipe with a weld about 1 inch thick running on the seam...its overkill for sure--but it adds peace of mind for me..Im not yet running on steam--but I do have experience working for a guy that builds and makes them. i hope im understanding you correclty--not sure what you mean by hydraulic tubing? is that the steel tubing for hydraulics?..stick with standard water pipe if possible...but your hydraulic steel tupe should work fine as far as i know...whats the I.D.? length etc?

but for the firetubes--the wall thickness is suggested to be quite thin because the pressure is not great on the tube walls INSIDE the boiler-this allows faster steam up time with thinner walled tubes...however for cost sake-use standard black water pipe- my suggestion-and its really only a suggestion--and it depends on how big you want your boiler.(8 inch dia?) you can use smaller diameter. the rule of thumb is to keep it in the 1 inch dia area. i.e. no bigger than 1.5 inches and no smaller than 1 inch for cleaning the tubes out. and to allow air flow.
what you need to do is simple--just calculate the surface area for each tube...im guessing 40 sq ft would be a lot for your boiler at 8 " dia.
in fact---

pm me and ill send you the plans for a small FT boiler -it will run a 5 hp easy but just scale it up for a larger engine...whats your engines IHP and rpms?- ill also send you a contact # to my friend who builds them and tell him Doug sent you..he is very helpful--just mind the time zone diff if you are anywhere but in the oregon area...
water tubes are viable too--i looked into a yarrow style--which to me is the easiest to build..it uses three small drums--two mud drums and the pressure tube--usually 12 inches diameter at 3/8th thick.
a down comer is sometimes not needed but add one anyway..
for a yarrow type-use small diameter pipe like 1/2 inch and use about 100 of them. you could use 1/2 inch i.d. tubing ...i just like the firetube better --for marine-i think they are better but with a crew--go with a WT. if alone a FT.

--its longer steam holding capacity and steady steaming allows for a smooth run--there are pros and cons to both types.
the upfront costs of a new diesel are at least three to four times the costs of equivelent powered steam engine and boiler(homemade)....then add fuel costs to that and steam starts to become more attractive...steam is more work--no doubt about it..you have to tender the engine and boiler--and you dont push a button and go.. but for running and for quiet running and torque..efficiency with props etc..nothing beats steam...in my opinion...

[Dave T]

Tugboat, hydraulic tubing is the tubing used to make hydraulic cylinders it is seamless and can withstand pressures in excess of 5000# cold. 8" bore is common on cranes and other large earth moving equipment it's often scrapped if the inside bore gets scored or if the equipment is scrapped. I used part of one to make my 50 ton press. I'm thinking for a firetube design using two pieces about 3' long mounted horizontally side by side about 1-1/2" apart inside a fire box that is baffled to make the fire and heat flow completely around these tubes and then exit through the firetubes into the flu. A draft blower would be used to force air into the firebox and could be controlled by pressure switches. One switch would turn the blower on say if boiler pressure dropped below 140# a second switch would turn the blower off when the pressure reached 160# with a relief valve set at 180# this should keep from wasting steam when not enough is being used. Here are a couple of pictures of my steam engine mounted on its stand connected to an alternator and pictures of my 50 ton press using the hydraulic tubing I'm talking about. I had to replace the ram seal it's back in operation now. Steam engines and boilers maybe too heavy for a small boat but they could be used to charge the batteries if you used electric power. Or the same for an electric car.

[tugboat]

Originally Posted by Dave T

Tugboat, Steam engines and boilers maybe too heavy for a small boat but they could be used to charge the batteries if you used electric power. Or the same for an electric car.

as i was looking at the pics--that same idea popped into my head...
use it to recharge batts for electric power...
but what size ev motors r u thinkng of?..remember-you cant put out more than you put in...so it might be redundant to run ev motors??

just a thought...

id have to see a diagram for your boiler system to really understand what your planning..but they r simple setups-so cant see any reason it wont work with some tweaking ....

nice work on the engine...have you steamed it up yet?..find out what rpms it likes to run at...

[Dave T]

Tugboat

I haven't done much research on electric motors yet. On my boat I used a 40# thrust trolling motor on the transom and a 55# on the bow. the 40# thrust moved the boat quite well. I couldn't get a good test with both motors because I had a 30 amp fuse on the 55 and long wires and it kept blowing the fuse at wide open throttle I've since shortened the wires and eliminated the fuse. The weather was terrible for maiden voyage so I couldn't do a good test. I'm now working on battery cradles and steering wheel assembly and I hope to have her ready for water again in two or three weeks.
The steam engine on 120 psi. runs 1100 rpm unloaded and drops to 800 under full load from the alternator into a low battery which was better than I expected.The alternator put out 40 amps at about 15 volts. This was on air because I don't have a boiler yet. I've done some work on the boiler design I could probably use a pump from a pressure washer for a boiler feed pump but I'm not sure how to control it. Somehow you have to sense the water level in the boiler maybe some type of float control or probes? If you used a closed system and used distilled water I would think it should reduce scale build up in the boiler. As far as cleaning the firetubes a hinged gasketed door on the back of the fire box would make that easy. Let me know if you have any sugestions or advice.

Dave T

[FAST FRED]

"but we are past world peak oil production-its all downhill from here..."

Pure nonsense , we have more proven reserves NOW than in any time in histiory.

With better drilling techniques the oil supply increase is growing daily.

And if the Russian concept of anaerobic oil is true , the earth is reproducing oil now.

FF

[tugboat]

Originally Posted by FAST FRED

"but we are past world peak oil production-its all downhill from here..."

Pure nonsense , we have more proven reserves NOW than in any time in histiory.

With better drilling techniques the oil supply increase is growing daily.

And if the Russian concept of anaerobic oil is true , the earth is reproducing oil now.

FF

hmmm interesting concept...id like to learn more about that--ive never heard of that theory before... please explain how the earth produces its own oil?



i would counter those arguments i.e.reserves: again- this is why they are "reserved' for when there is no oil...

hence it wont get used- and isnt it true that the u.s. has a huge reserve?..but other nations dont?

And if the earth isnt producing its own oil? then what?

to be honest--i hope your right..but i do know for certain gas prices are going up-- that is a fact... and they wont be going down...

[powerabout]

I know plenty of oil fields that are pumping less everyday even with huge added cost production techniques
Let me know when they get another saudi...
Biggest issue is no-one knows how much oil is pumped everyday

[edsrace]

I vaguely recall an article I read few yrs back about a car that smokey yunick had modded for better use of fuel. He heated the fuel air mixture I belive right under the carb. The claim was that the fuel stays in suspension better as a vapor thus a more complete cumbustion. I cant recall the milage claim or the details of the project but he was a big name in auto racing so a quick google search might lead to it.
There is also 6 cycle engines that use fuel for a few power strokes and water uses the heat trapped in the cylinder to create stem for a couple power strokes.
I have messed with hydrogen a little just enough to know that the electric h2o gen. I built will make useable gasses untill my batt gets drained since the alt couldnt keep up. I stopped there and tossed it on the shelf for now.
I have a methanol inj. of sorts on my car now. Couldnt tell you what if any my consumption has chanfed but it does seem to help combat preignition as well as carbon buildup.

[Boston]

Hot fuel and cold air is what works best on my truck. I burn a mix of motor oil and biodiesel. Costs me about 17cents a gallon and runs like a bat outa hell.

[edsrace]

I vaguely recall a car smokey yunick modded for better use of fuel. I think it was called the hot vapor engine. the idea behind it was that by heating the fuel/air charge the fuel will stay in suspension as a vapor thus a more complete combustion.
There are six cycle engines that use fuel for a power stroke or two then use water and the heat from the combustion to make steam for the next couple power strokes.
Maybe someone smarter than I can tell me as far as ethenol goes why not sort the garbage that is going into landfills and use the fermentables for fuel leave the corn for food and whiskey? Not to mention all the recycleables that could be reclaimed.
Im suprised not to see anything on here about methane. There are dairy farms in my area that trap the methane off the manure and use it to run generators.

[Boston]

No clue
the way it was explained to me was that if you heat the fuel it atomizes better

[edsrace]

Idk didnt think it posted lol

[FAST FRED]

which can tick along at 5 knots on a few sticks of wood an hour

The comparison then would not be against 2x200HP diesels but against a tiny single cylinder burning 1/5 gph .

FF

[assycat]

Originally Posted by FAST FRED

which can tick along at 5 knots on a few sticks of wood an hour

The comparison then would not be against 2x200HP diesels but against a tiny single cylinder burning 1/5 gph .

FF

in that application yes--but for pure power such as in a tugboat--the torque of two 15 hp engines geared 3:1 would easily compare or exceed bolard pull a twin diesels of 75 hp ea. do the math torque = hp x 5252 / rpms-- the dif being the steam enigne is 100% torque at 0 rpms where the diesel develops its torque at around the 2000 rpm mark and higher. so the diesel will get you to the jobsite quicker--but steam will be strongr at less hp. now what if we had two steam engines of 100 hp ea vs two diesels at 100 hp each

steam: 100 x 5252/ 500 = 1050 ft-lbs torque (x 2 engines) 5 knots cruise
diesel 100 x 5252/2000 = 252 ft-lbs(x2 engines) 10 knots cruise

which one is more powerful??

the diff is the diesels fire up quicker...and have more speed

and may cost more although thats debatable since the amount of btu's needed for 100 hp engines is pretty substantial...id have to do the math on that for wood though large volumes but cheaper. the onoly reason steam went obsolete at the time 2 factors 1. more crew needed 2. slower
today all that would change...modern high tech approaches solve these issues.

in this case steam 500rpm, diesel- 2000-3000 for the above

[Dave T]

If we compare a diesel developing 252 ft. lbs. torque at 2000 rpm geared 3 to 1 then 756 ft lbs. to the prop 667 rpm

A steam engine 1050 ft. lbs. torque at 500 rpm geared 1.38 to 1 then 756 ft. lbs. to the prop 694 rpm. If everything else is the same the steam engine should be faster with the same power.


Dave T