Sidewheels, where to place them?

[kno3]

Hello,

I'm continuing my research on model sidewheelers with another question:
Where should the paddlewheels be placed, in the middle of the hull, towards the stern or the bow? I am planning to build a freelance model, so I'm trying to find the best position.

Most sidewheelers I have seen seem to have them pretty much in a central position, but I have seen a few with the sidewheels close to the stern too and even one with the wheels closer to the bow.

Are there any advantages related to the longitudinal placement of the paddlewheels?

[Eddy Matthews]

It pretty much depends on which type of ship your modelling, an ocean going paddler or a river paddler? What sort of era? Passenger carrying or a workboat such as a towboat or a tug?

Eddy

[kno3]

I have no idea (yet) what it is going to look like. I am going to build the hull around the engine and paddlewheels.

So for the moment, let's consider an ideal hull (we can keep aspects like engine placement out of the discussion for now). Where would you place the paddlewheels?

[Eddy Matthews]

I have no idea (yet) what it is going to look like. I am going to build the hull around the engine and paddlewheels.

So for the moment, let's consider an ideal hull (we can keep aspects like engine placement out of the discussion for now). Where would you place the paddlewheels?

In that case I'm afraid your asking a question that is impossible to answer

An ideal hull doesn't exist, at least not in the real world! There are always compromises depending on it's function and the environment it will be used in. The best hull for a tug will be nothing like the best hull for a passenger carrying vessel or a cargo vessel, and to take it to an extreme, it will be nothing like the hull needed for a boat that is designed to break the world water speed record! All of which would probably need a slightly different paddlewheel position....

Then we go back to the era of the vessel - Early paddlers (pre 1860 ish) were nothing like the vessels we see today, and their paddlewheel position was different to a more modern vessel.

Lake or river paddlers are different to ocean going ships....

So unless you can be much more specific, there isn't an answer to your question.

Eddy

[derekwarner_decoy]

Hi PD's....please re-think your concept kno3.....it is better to use a plan & build to the plan it will be so much less frustrating 

Learn from the mistakes of others [derekwarner_decoy] where I drew my own plans in Y2000 from two postage stamp size photographs & still have not finished the build  - Derek

[kno3]

Derek, I already have some experience with freelancing, so that shouldn't be a big problem. Besides, I think designing my own boat is so much more fun than copying what someone else has done. I know I'm going to run into a lot of problems, but I regard them as part of the challenge.

Eddy, I'm trying to have a theoretical discussion, for now, so I'd like to hear all ideas regarding paddlewheel placement, no matter what type of ship it is. Forget the ideal hull concept. Just say if you know why the paddlewheels are placed in a certain way on a ship you are familiar with.

[steamboatmodel]

One on each side and as far apart as possible, with independent control of each.
Regards,
Gerald

[mjt60a]

I suspect there isn't really an answer to this question but my (unscientific! ) view is this...
1...The engine and boiler are (usually) as close together as possible to keep steam pipes as short as they can be and this engine/boiler, being the heaviest item inside the hull, is going to be around the mid point so that the hull will float level.
2...The best position for the wheels is at the mid point (of the hull) so the crankshaft/paddleshaft is nearest the boiler and the cylinders further from it.
3...the boiler is usually forward of the crank in passenger ships, behind it in tugs.
4...in practice, most passenger ships will have the wheels close to the centre but slightly toward the rear of the hull and tugs have the wheels somewhat forward of the centre.
I have absolutely no evidence to back any of this up, I'm just looking at pictures and models!

[mjt60a]

...the last picture is Tattershall Castle. unusually for a passenger ship, the boiler is behind the engine and the 'driver'/engineer sits facing backwards.... The wheels appear to be pretty much in the centre of the hull (can't be bothered to check the plan at this time of the night to see if it really is!)
then again, some ships (solent queen, lorna doone) had two boilers with the engine between them, there really doesn't seem to be any 'right' answer...
would it maybe be worth choosing a ship you like the look of and designing your model with that style in mind?    that's what I did with this one, it was 'loosely' based on other model tugs I'd seen but with a few details changed to the way I wanted them...   

[kno3]

mjt60a,

Thanks for the pictures and helpful answer. I hadn't realised that tugs tend to have paddlewheels slightly towards the bow.
Your model tug looks very nice. I might make mine along similar lines.

Did you make the paddlewheels yourself, or did you buy them?
What method did you use to build the hull?

[mjt60a]

I made the paddlewheels myself from styrene sheet, the hull is made from newspaper over a balsa frame! but it's covered with fibreglass cloth and resin for strength and waterproofing
check out this thread (from quite a long time ago) for the hull - http://www.paddleducks.co.uk/smf/index.php?topic=370.0
and this -  for the wheels!

[Roderick Smith]

I am generally looking at much smaller paddleboats, mainly Australian wood-fired ones.  Even with these, there are variations.
The most common was to have the wheels at the centre or slightly aft.
The boiler ran forwards from the paddleshaft, with the cylinders mounted on the boiler smokebox or extension (as most were based on traction-engine design).  This placed the firebox fowards, with ready access to the stack of firewood which would be loaded across the bow when the boat nudged into a bank for wooding up.  This also placed the fireman in the relatively-cool airflow at the open front (important in the hot inland climate).  Someone else has observed that Australian boats had open engine rooms; north American ones were enclosed.
Mentioned in Paddleducks: The other important design aspect is that the paddles serve the rear taper of the hull.  AFAIK this was to provide water flow to the rudder for precise steering (vital in Australia's winding rivers, with shallow spots and snags to avoid).  It may also be a requirement for propulsion efficiency, reducing drag caused by back currents.

In 2008, I cruised on PS Waimarie in NZ: a cooler climate and coal fuel.  It was arranged far more like a small version of the batch just displayed in this thread to show the considerable variations.

Regards,
Roderick B Smith
Rail News Victoria Editor

[kno3]

Thanks Roderick. I have a question. You say:

Mentioned in Paddleducks: The other important design aspect is that the paddles serve the rear taper of the hull.  AFAIK this was to provide water flow to the rudder for precise steering (vital in Australia's winding rivers, with shallow spots and snags to avoid).  It may also be a requirement for propulsion efficiency, reducing drag caused by back currents.

What does serving the rear taper mean? Do you have a picture?

[Roderick Smith]

Hi,
I am not a boat builder.  I got that statement from Michael's modification to his Sundowner hull, see
www.paddleducks.co.uk/smf/index.php?topic=3324.0
He replaced the square stern with a tapered one.

Somebody else posted 'One on each side, preferably with independent control'.

Search under Hungary or Russia, and photos have been posted of a paddleboat with two paddles on one side (but it did have two on the other as well).

Independent control can be a hazard.  I was an a friend's boat, in which he had cut out one paddle to come into a lock in tricky currents and wind.  He forgot to put it back in.  The boat went to leave the lock, and bashed into a wall.  Most of my handling training is in boats with paddles fixed to a shaft.  Nobody has been sufficiently brave to let me dock one yet.  Certainly, departure seems to rely on dextrous use of spring lines (four main cases: two directions of current matched with two directions of wind).

I don't know about boiler placement for a quarterwheeler, or even what the perceived advantages of a quarterwheeler were.

Regards,
Roderick B Smith
Rail News Victoria Editor

[derekwarner_decoy]

Hi PD's...'taper of the stern' actually achieves two functions

1) the actual underwater hull lines tapering toward the rudder act in a similar function to an aeroplane wing  ...so the water exiting the hull dips into a void of less hull space [in the taper] & therefore creates lower pressure area
2) this lower pressure void then directs the flow of fluid toward & over the rudder surface & hence improve steerage

This is of significient benefit to a paddler with 'taper of stern' over a blunt ended paddle vessel where the rudder would just amble in eddy currents

  ...no ....just think about it for a while  ....Derek