Steam engine for a sternwheeler

[apointofview]

Yes I'm going to shoot for the open decks like the Liberty Belle. It seems to have two cores in the center for the stairways, and they probably gives the floors a lot of rigidity. The forward one may be in the way a bit for the boiler, but all that metal will sit low in the hull under the smoke stack as close to the belly as possible to try to lower the CG. I guess lots of balsa wood for the superstructure. All those posts will test my commitment to this project !!

As for displacement calcs, from what I gather I am supposed to determine the area of the hull that will be in the water and then figure out the volume of fresh water it will displace to understand the load it can support. Is that right ? I found a online calculator here http://www.blueheronwings.com/bh/comps/bdesign.html
I hope its right because thats what I used....
Pete

 

[Dave Sohlstrom]

Pete

I'm not sure that calculator is accurate. The numbers will give a shape of a shoe box sitting in water and not take into account the hull shape.
Delfship is a free 3d hull design tool that will give you displacement. It takes a while to get your head around how it works.
The closer you can get to knowing the displacement the better.

Here is a link to delfship http://www.delftship.net/DELFTship/index.php/delftship/delftship-free

Dave

 

[bouch]

Dave,
Yep your right but since I didnt plan ahead at all I am forced to keep the width at least 16 inches to fit the engine and boiler as built. The length is already 55 inches which is making it really big. Much bigger and dealing with transporting and storage will be a problem. Also the boat I am using as a pattern isnt that far off, I dont think. It might be a little unrealistic to the real riverboats but it does exist and it is a real full scale boat. I tried to get Disney to send/sell me a few drawings of their boat but all I got was the telephone number to their legal dept !!
Pete

I tried to get some info about the Disney World Railroad locos that isn't in Michael Brogies book, and was told that it was all "proprietary information". The photos you have are probably all the info you'll ever get unless you find a web site where someone has already done the scaling from photos!

Mike

 

[apointofview]

Thanks Dave,
I will download that and try to get my hull plugged in to it. I really want to get a good idea of how deep it will settle into the water. The tough part is figuring out the weight of the hull. The boiler, engine and other bits are easy since they exist.

Mike,
Thats pretty cheesy of The Mouse ! I always thought that imitation is the sincerest form of flattery. If someone is running around displaying something modeled from their parks it seems like free advertising. If I was building and selling them that would be different, but just for my enjoyment.....they need to lighten up a bit

Pete

 

[bjo]

You aren't far off on your dimensions of the boat you are modeling. At least, if this and a few other sites are correct. http://www.wcdept478.com/MagicKingdom2.htm
Magic Kingdom 2 was renamed Richard F Irvine, then to Liberty Belle

 

[RichD]

Wow!
I just read this thread start to finish.

Pete,
You're very talented. I've learned a lot about thinking "outside the box" from your posts. Thank you so much for all the details and pictures/videos.

On the draft question, do you think you could fill the hull with water while measuring the total gallons used. Then use the 8.3 lbs/gallon rule to get an estimate on where the hull will sit draft-wise? Just a thought.

Rich

 

[apointofview]

bjo - yep I think for my purposes it will be close enough, I have more changes to do, but there is gonna have to be a pause, I am going to rebuild an old s10 with my son. He has started to show an interest in the project so I gotta seize the moment.

Rich - Thanks a lot, I am just a hack that is winging it. I get my inspiration from the great work I see these guys display on this site. Its amazing what you can learn from the internet !!

As far as the displacement problem, I think the water idea would work except I really dont have any idea how much the boat structure will weigh. The foam mock-up isnt good enough to float or hold water so the watertight hull will have to be built on calculation. I tried to download the Delfship free 3d hull design tool that Dave pointed out to me to get that info but my old computer cant run it. I will have to borrow my daughters laptop when she isnt needing it for college to run it. That seems like to most accurate way to get the dimensions correct without cutting a bunch of expensive wood.

Pete

 

[apointofview]

For the displacement and balance calculations, I measured and measured. I fiddled with a seesaw arrangement for all the heavy metal parts, and ended up with numbers that looked good to me. I did download the program Dave recomended and it looks like it would be perfect, except for the fact that I dont have a clue how to get my hull shape into the program, and I dont have the time to figure out how. I just went with my simple math.



It was time to see if I ended up with a reasonable setup for weight distribution in real life. Instead of trying to build a watertight hull , I went with reinforcing the foamy mockup to support the bottom of the hull so when the propulsion components were place on the foam they would deflect the foam only a small amount so as not to mess with my displacement calculations


Then I skinned the bottom of the hull with foam and then water proofed it with a piece of plastic sheet that was just taped to the boat above the waterline.


Marked some depth lines measured from the bottom of the foam


I built a ' dry dock' and lined it with more plastic and put the boat and all its hardware in it along with the 5 lbs of ballast that my calculations said I would need. Threw in the garden hose and started filling.



The hull floated right about where the math said it should and was only about a 1/4 in off from bow to stern. That was most likely due to the fact that the bow sides have a curve to them and my geometry layout just made nice triangles with no curves so the real area was a little bigger. I am thrilled !! The hull weighs 28 pounds with the ballast and the displacement calcs said it should sink 1.5 inches into the water. I added 14oz to the bow in the form of a bowl and water to make the hull level. With everthing balanced the hull sank about 1 3/8 inches !! Not bad I loaded the hull down with another 12 pounds to bring the hull 2 inches down into the water. At that level the paddle sits just where it should in the water, one bucket will be almost all the way in the water and the leading and lagging buckets are partially in the water and the buckets leading and lagging those are dry. From what I have read thats what I am to shoot for.
So with a 2 inch draft the hull, as is, it can support 41 pounds !!! Thats not light. I dont know if the boat will be that weight when its made of wood and glass but at least I can predict fairly accurately what will happen and where the paddle will have to sit. I also know right where the balance point of the hull is so I learned a lot. The shots of the paddle in the water are at the 1 3/8 depth not the 2 inches I will shoot for on the final wood hull.








Lots of fun today
Pete

 

[RonGinger]

Nice work, I like that foam model and plastic sheet. Nothing like doing a little testing to confirm the math and set you at ease before you start to build the hull.

 

[barnesrickw]

Your boat looks great. I've read some history on river steamers, and I don't think floating was a priority. Catching fire and exploding was, but floating was optional.

 

[apointofview]

RonGinger - Thanks, the test went well, it was so easy that I am going to mess with the lines of the hull some more to get the look I want and just float it some more.

barnesrickw - Thats funny, you are right those full scale boats seemed explode and sink all the time. I figure if my boiler gets away from me and takes out the boat then at least I can say I was trying to be historically accurate !

Pete

 

[barnesrickw]

I wish you luck, but just in case, be sure to film it.

View attachment ImageUploadedByModel Engines1424656296.067232.jpg

 

[apointofview]

That sure is an awful picture !

Just a quick update on the mock-up progress. Not a bunch of changes but I am slowly getting the idea of what I want it to look like. There is little to no precision in this part of the build. I just am exploring options to the shape of the boat. Looks like the superstructure will be just a shell. There is a lot going on for the power plant that takes up a bunch of room.

Pete

 

[barnesrickw]

That is beautiful.

 

[crueby]

Pete - I love your foam and tape approach to mocking it up. Several years ago I was laying out the cockpit seats/rail height/footroom on a sailboat (full size) and used stacks of lumber, extension cords, and chair backs to make a test setup that I could sit in to make sure it would be comfortable. Super low tech but it worked! The old school test for setting the balance point of sailboat center of lateral resistance involve cutting out a carboard profile and balancing it on a pencil. Go for what is simple, quick, and works, not what the computer simulation says (this coming from a retired computer engineer!)

Keep up the great work, been watching the build with interest.

Chris

 

[barnesrickw]

Will you be covering it with epoxy such as the West System, or System Three?

 

[apointofview]

I was figuring on fiber glassing the bottom of the hull if thats what you mean. I'll look up those two products you mentioned
Pete

 

[apointofview]

Just a little progress. A couple of details, just to think things out.
Looks like I am going to add lights like the Disney boat has. I had a small strip of LED lights left over from the under cabinet lighting I put in our kitchen just to test it out. It should look good.
I bought some thin plywood from the lumber yard, so the cutting of the real thing will start soon --- I hope.

The last pic shows where most of my spare time is going.

Pete

 

[barnesrickw]

That truck engine is never gonna fit.

 

[apointofview]

Its actually the one that came out. The camera makes it look bigger than it is. Its just a cute little 2.8 we are just gonna put in a fresh long block with the same displacement.