Requesting Small Sternwheeler hull design and analysis help

You have a good chance of causing the suction you are trying to avoid as you lay the boat over on one side of the vee or the other as this suddenly becomes the flat bottom you don't want. That is why I suggested a small flat in the middle of his design... to add another angle to the mix and reduce the amount of flat area. In truth the more chines or angles you can get the more it will approximate a somewhat flattened rounded shape and the easier it will be to roll around in the mud. However your need for shallowness means that you have to have a wide flat weight supporting area. WidRaf's model is a good compromise to start with and I think adding the small flat oval in the middle will help break up any large areas that will generate suction in the mud. If it wouldn't be disastrous to the water flow I would suggest you have your bottom panels like ripple chips vertically to trap air and prevent any suction from occurring in the first place.

 

These two have a slight v bottom, although you would have to upsweep the bottom at the stern for water for the wheel and better displacement performance.

If the muck where you will boat is as soft and gooey as it sounds, will a slight v bottom even help keep it from getting stuck?

The upfront rudder on the Showboat has always seemed like a bad idea, mainly because it eliminates beaching the boat for easy people access on and off.

http://www.svensons.com/boat/?p=HouseBoats/BayouBelle

http://www.svensons.com/boat/?p=HouseBoats/FloatAhome

http://www.svensons.com/boat/

 

A narrow flat may work, just seen this much suck a flat-bottom under, the next time the water rose.

I am thinking that, with angled gunwales, almost no matter how the water rises, it will do so unevenly, so if I have that low dead-rise, underneath, it should allow water under the hull sooner. The flat-bottom was an average aluminum boat with square sides, as well.

 

WinRaf... could you attach that .fbm (if it is one) so I can play with it a bit?

 

That upswept stern section is what I'm trying to put under the jon-boat, with the keel shape of the Pango.

That front rudder wasn't the brightest design idea, in my opinion. I've seen canard model aircraft with them, even the Wright Bros. did so successfully, but I don't see it anywhere else in the boating world. Even the guy that has built 3 generations of sternwheelers based directly off of Showboat has ditched it. Unlike me, he has deeper water lakes to run on.

My initial idea was to modify the Showboat, but it just doesn't DO what it should, for this river-bottom.

 

Just a reminder... I'm using Windows Paint...

NONE of the hull mods I have done are in any design program. I would appreciate it if someone could translate them into one and see how they do. None of the dimensional data is accurate.

I'm trying to put an ~12ft long, by 6ft 6in to 7ft 6in wide opening down into the hull, from as close to the stern as practical, to a 4 ft pilot-house at foredeck level, with about 4 ft of deck ahead of that. Side decks will fold up, to get back to the 7 ft 6 in beam (could go 8 ft 6 in at the top of the gunwales, as long as that allows clearance for the wheel-wells of the trailer). Behind the transom, will be the wheel-arms/sponsons, to support the paddleweel, regardless of it being powered, or freewheeling. Adding a shelf to the transom, between the sponsons will allow mounting of the electric drive units (looking better as converted lower-units).

One goal is to keep the deck low enough for swimmers to haul aboard, and allow easy fishing, like many of the flats-boats...

I figure ~24in from keel to deck, with 6in to 9in below the water-line should be fine. I'll have combing around the opening into the hull and inside the perimeter of the pilot-house, to raise the effective freeboard.

 

I posted those boats not as something for you to build, but mostly as an example of how boats can be framed and built, pretty much to whatever shape you want.

Here's a thread that might have ideas on how to power the wheels etc. Post # 34 is a boat 30' x 9', about the size you want.

http://www.boatdesign.net/forums/boat-design/hull-design-side-paddlewheeler-need-help-18125.html

 

Glen-L Electric Drive Lower-Unit conversion

Link to the info page for the Glen-L Electric Drive...

http://www.glen-l.com/designs/special/electricdrive.html

Slideshow of the Glen-L Electric Drive conversion...
Think I'd use toothed-bell and pulleys...

http://www.glen-l.com/designs/special/elecdr1.html

Link to a boat that uses it...

http://www.glen-l.com/designs/special/lovoltage.html

 

Glen-L E.D. conventional...

Compare this...



to this...



With clear water under the stern, I could go with the conventional-conversion, moving weight forward, rather than hanging it off the transom

 

Thank you!
Had skimmed it. Had not noticed the doc on efficiency calculations...

home.clara.net/gmatkin/pwheel.rtf

 

Incidentally, my own interest are slightly varied from yours.

In a small boat not meant for speed the scantlings for the varied members of a wheel, there are rules available in some old versions of Seaton's you can find in PDF form online, are not necessarily demanding and could be possibly built from or stiffened with GRP (or even carbon fiber if I got ambitious) enabling the construction of dismountable sidewheels for towing. So a boat that, including wheels, may have a 12' of so maximum beam on the water could still be transported if desired without all that wide load nonsense.

The initial wheel design could be sorted out before building the hull. If driven by electric motors (powered by an on board generator) the only things I'd absolutely have to get right the first time around would be the system to mount them ... which would be different than any outboard motor of course. That would permit later efforts to shave weight or even change the design.

The actual placement of the wheels would likely be farther aft, in a "Quarterwheel" configuration to facilitate launch and recovery from a trailer.


Oh, and btw, that one model boat page I linked to had some details for regular radial wheels along with info on feathering. I don't know if I've mentioned Seaton's before but there are likewise rules for sizing wheels there too.

 

General rule of thumb on wheels is regardless of diameter, should have one bucket straight down, one leaving the water and one entering the water. Diameter, minus the buckets. on this one will be from waterline to a bucket width below the cabin roof, somewhere around 6ft. At least initially, the wheel will freewheel in the current, whether under power, or not.

If you're interested in side wheels, I saw a nice aerator design, with a kooked edge to lift water, but, switched for normal forward, it might actually be more efficient. Was thinking of trying it, later.

If you can spot a link to the Seaton stuff, I'd appreciate it!

 

Here's one: http://books.google.com/books/about/Seaton_Rounthwaite_s_pocket_book_of_mari.html?id=Fl8OAAAAYAAJ

There are several editions available for free, to at least 1922, and while they are different in parts they are mostly similar.

One thing about the scantling rules: they relate to the diameter of the boss of the driving engine. That makes sense given that the crank is sized by power but it means that you may need to fudge figures since back in the day the strength of metal in the engine crank shaft and the sort of materials used in paddlewheels were similar whereas a modern engine is likely gonna have better material in its crankshaft than what we'd poor slobs may be even able to attempt to work. On the other hand we do have CAM cutting services widely available to us to reduce our bit to using a few basic tools.

 

Thanks! Found the Google Books version to read online, for free, at lest for now. One of the best book-sets I ever had was some sort of machinists tricks of the trade kind of things. Be damned if I remember any of it, even forget what the things looked like.

 

lewisboats,

I'm italian, so i draw in metric sistem. The post n° 126 is in metric. The dimensions traslate in imperial sistem are:
length 20 ft
beam 8 ft
draft 1 ft
medium esdisplacement 0.8 ton

These dimensions are those of a normal container, and allow the trailer with the car in all countries of the world

this are the right dimension that i think is better for the proget in this topic, because for to have: boat + normal enging + elettric engin + fuel + battery + cabin + wheel + 4 people on board + fishing things + boxes of beer + food and water...that is the size for a good displacement.
The boat can be built easy in plywood 12 mm. - means 1/2 inch.

I tried to make the changes to the V bottom that you've suggested, but the resistance increases very much.