Stability

[Rob Bruce]

Glyn Lancaster Jones of the Traditional Boat Shop in Wales, designer and builder of the Swiss paddle wheeler and of "Minette" see Jersey Lily argues that the sponsons for his paddle wheelers, ie the timber framing supports for the wheels do actually add a significant amount of additional buoyancy. Glyn's designs have small diameter wheels with the shafts passing though the side planks rather sitting at the deck level. The comment was made to me via an email because as an Aussie I was a bit concerned by the rather narrow hulls in Glyn's little paddle wheelers (4'6"). Of course his hulls are kept narrow to work the UK canals which is not an issue for us boaties down-under.
Rob

[Eddy Matthews]

I would love to know how Mr Lancaster Jones manages to come to that conclusion.... The sponsons do not (or should not) touch the water, so all they add is extra weight to each side of the hull, and cannot possibly add to the vessels stability or bouyancy. The exact oppossite is true, they ADD to the vessels displacement, therefore decreasing bouyancy, and their position and weight can only DECREASE the vessels stability. It's the laws of physics....

For someone who claims to be a boat designer I'm amazed at his statement!

Regards
Eddy

[Scout0098]

maybe he maens "emergency" buoyancy, you know like marine foam in case he sinks?

[derekwarner_decoy]

Hi PD's.....I can only think there may be some misunderstanding of the authors comments or works......does anyone have a copy to scan & post here? ....as one page would not breach any Copyright.........

Getting closer to our big OZ day  ..............Derek............

[mjt60a]

....I am afraid the shorter height would mean smaller paddle wheels and thus less effeciancy/power.... Does anyone have any ideas/suggestions?

How about if you make feathering wheels? having the floats enter the water at a relatively upright angle should enable the use of a smaller wheel, more deeply immersed.
 Placing a 'simple' paddlewheel deeper in the water causes the fixed floats to push water down as they enter and lift it as they leave giving no extra motive force but causing the engine to work harder...
P V Tamati (?) in New Zealand appears to have quite small wheels (apparently based on those fitted to Maid of the Loch)

[Rob Bruce]

I think this discussion is working at cross purposes. Not all boats are equal and my understanding is that some of the smaller paddle wheelers do indeed obtain some reserve buoyancy advantage from their sponsons in much the same way as the floats on a sailing trimaran do skim or kiss the water under certain conditions.
This is what I understand is happening in the small paddle wheelers designed by Glyn Lancaster-Jones. In fact the "Minette" at 20' long and 4'6" beam (see Jersey Lily in the link below) is a very narrow hull. However the wheels at 28" diameter locate the drive shaft at about 14" up from the bottom of the hull. Glyn actually constructs the sponsons of full section timbers with positive buoyancy acting like "training wheels" and are designed to limit the amount of list of the hull. I have a quote somewhere from Glyn on this subject and I will add it later if anybody is interested.
Another example is the little saloon paddle wheeler "Firecrest" (see also link below): 15'3" loa and a very modest 4' hull beam with 24" diameter wheels. This time the drive shaft is only 12" up from the bottom and with 9" draft the bottom of the sponsons are just skimming the tops of the waves. In this design the sponsons are actually boxes deep enough to use as additional storage with the top of the sponson boxes actually at deck level.
However Eddie I readily admit that a larger paddle wheeler with steel wheels hanging over the side of the hull with the drive shaft at gunwale level or above, would certainly offer no stability advantage by such a rig.
I have actually been sent a photo copy of the article"Firecrest is a trailable paddle steamer" reprinted from an old copy of "live Steam" magazine. An interesting little boat with some very clever features.
http://www.steamboat.org.uk/register/html/jers0289.htm  for "Jersey Lilie/Minette".
http://www.steamboat.org.uk/register/html/fire0210.htm   for "Firecrest"
Both links have photos of sponsons just skimming the water.
Hope this helps.
Rob

[Rob Bruce]

I have now found the quote from Glyn Lancaster-Jones on the stability of the "Minette" design and the advantages of the sponsons:

“The stability of a side wheeler is tremendous, as there is enough buoyancy in the sponson structure and deck to make it very difficult to dunk them, let alone push one of them right under.   I have stood on them, and they barely touch the surface.   They are a plywood deck on a frame with support brackets underneath.  Those fore and aft of the paddle wheel are taken right through the hull skin and attached to full or partial bulkheads.   The paddle beam as it is called spanning these two is made very strong to protect the wheel from damage and to mount the "star-centre" for the feathering mechanism.   Where possible I make the upper part of the paddle-box removable.”
These comments are not for all paddle wheelers and were sent to me last year via email in relationship to the question of the stability of the small side paddle wheelers. Hence I am giving you a copy of a personal email which I trust Glyn approves.
Rob

[Scout0098]

I noticed a lot of the smaller wheels were feathered and I thought about doing the same...problem is I don't know how they work  I've seen pictures of them and from what I can gather, the floats pivot, I can see they pivot when the wheel comes around and the blades fall forward to act like a plow on the water, but after they leave the water on the back side of the wheel what do they do? And why do they do it?

[Scout0098]

....I am afraid the shorter height would mean smaller paddle wheels and thus less effeciancy/power.... Does anyone have any ideas/suggestions?

How about if you make feathering wheels? having the floats enter the water at a relatively upright angle should enable the use of a smaller wheel, more deeply immersed.
 Placing a 'simple' paddlewheel deeper in the water causes the fixed floats to push water down as they enter and lift it as they leave giving no extra motive force but causing the engine to work harder...
P V Tamati (?) in New Zealand appears to have quite small wheels (apparently based on those fitted to Maid of the Loch)

I decided that I was not going to run the axle thru the hall as I had originally planned so my Paddle wheel will be 27" in diameter. (Anything bigger would look odd) with that plan the paddles would be dipping into the water about 6 or so inches. that seemed to me to be a reasonable depth because we are going for shallow to reduce the strain on the engine? any ideas very welcome

[Rob Bruce]

My experience is only with the small paddlers: but the blades need to be fully immersed at the bottom of the stroke. In most small paddle wheelers this means that they sit pretty much in line with the bottom of the hull and say with 6" draft the blades are about 6" deep. Obviously this is not true for the larger hulls.
The most common feathering wheels are known as Morgan Wheels. Google has many links on this subject and the one below is one of the clearest:
http://nautarch.tamu.edu/PROJECTS/denbigh/WHEEL.HTM
My next paddler will be electric powered and somewhere between 17' and 20' feet long and at this stage I do not intend to fit feathering wheels. I'm not sure they are worth the extra effort and expense, but others may disagree. Certainly many of the UK builders of small paddle wheelers like them. I will follow Glyn Lancaster-Jones advice and construct the wheels and sponsons in such a way that I can retrofit the Morgan type wheels if I feel the hull needs this modification.
Hope this helps.
We are all learners.
Rob

[Scout0098]

Hey Rob, thanks for the link! when I make my paddles they are going to be immersed the 6' thing kinda worries me though, not sure if 6' is adequete to propel the boat. when I first started this project, I ran across the "paddellac." you can google it, they have a few videos on youtube.com. (they also have a website which unfortunately I can't view anymore because of a filter at work, darn!)  I wrote to the guys that built it and they said their floats are about 12" in the water at the bottom stroke. that seemed a bit deep to me.......from what I've read so far it seems that shallow and wide are better than narrow and deep. But I'm still learning lol. 

Your boat sounds like it'll be pretty cool, Electric huh? I like the idea. don'r know if you've seen it already but they have a sternwheeler called the "New Era." it's electric and has solar panels. It would be nice to cruise around without hearing a bunch of engine noise. I'd try it too but the currents around here are pretty decent and I have visions of a dead battery and being carried out into the Atlantic lol Which is also the reason I want to get my paddle wheels right  What type of hull do you plan to use?

[Rob Bruce]

Size of blades or paddle is determined by a number of factors as is the design of props.You can seek the advice of a professional in the field (especially for traditional props), or you follow the advice of the designer or builder. Both the links above for "Jersey Lily" and "Firecrest" detail the size of the blades. The 6" deep blades I will be using are designed around a specific boat.
I am following the advice of Glyn Lancaster-Jones for my boat which will be based on the "Minette" and "Firecrest" designs. Yes I have seen the details of the "New era". I posted details at the end of last year. I'm a member of the Electric Boat Assoc. UK.
My little paddle wheeler will use an existing motor, controller and batteries from another project. Our rivers here are very gentle with tidal races only a few knots so good planning or just drop anchor when tides are on the peak. My first electric boat used a large trolling motor and we never looked like being washed out to sea!
But range must be calculated. I'm going for about 5 hours max cruising, but with solar panels on the roof that will be extended. That's another subject.
Rob

[Scout0098]

I looked at Jersy lily and Firecrest and I know that the blades are 6" deep but the issue I'm faceing now is how wide the blades need to be I was thinking maybe 12 inches wide but I'm wondering if I could go narrower. My boat's hull from what I've seen most closy resembles the L'il Sipp. It's double ended and about 14' long with a 5' beam. My engine is half the size of Li'l Sipp though.

5 hours sounds like a good max cruising, that's pretty good for a day out on the water or out fishing. How big will the electric motor be? That's pretty nice that you don't have to worry about the tides too much. I thought about the dropping anchor idea but around here in warm weather if you stand still, you'd get eaten alive by mesquitos and Greenheads (large biting flys that swarm around the marshes. and when they bite they pretty much take a chunk out of your skin). 

[Rob Bruce]

If you think of paddle wheels in the same way as you think of boat props. If you look at a small outboard of say 2hp and then compare the prop size to say a 50hp motor. The greater the engine power then there is the ability to take a larger bight out of the water with a larger prop.
I seem to remember seeing somewhere in the PD site some calculations for wheel design but there are two other ways to go.
First work with a builder who has actually built a paddle wheeler that works. Or look at sites where there are details of wheel and blade sizes on boats that are working. But note also the revs and the power output of the engine. The link below is to another small paddle wheeler "Firecrest" but have a look through that site of steamers (not too many paddle wheelers) just work through the alphabetical list and you see what size blades others are using. In some cases you can follow up and actually contact the builder. I posted a inquiry through the Steamboat site and got a reply from a fellow  Aussie who sent me a photocopy of two old magazine articles by the builder/designer of the little "Firecrest" paddle wheeler.
 www.steamboat.org.uk/register/html/fire0210.htm
The second approach is have a go. Give it your best shot and experiment. Trial and error works. You might get it right first time if you have done your homework. If not keep trying until you get it right.
I already have a 750watt permanent magnet electric motor running on 36volts with the necessary PWM controller etc. I will be using a 25:1 reduction in two stages to get the revs down to a cruising speed of 80rpm. I have decided that a little boat of about 15 feet will do me at this stage. When I get into the building stage I will post photos as I go. The wheels on "Firecrest" are 6 inches deep and 9 inches wide and 8 floats.
Rob

[Scout0098]

9" sounds about right for my floats, I was reading some old PaddleDuck posts and came across the rule of 3rds how the float with should be about a 3rd of the diameter of the wheel. I think I'll go with 10" wide floats on my boat which is a little bigger than a 3rd (my diameter being 27") so we will see how it works out. Now I just have to go get the materials and wait for it to warm up a bit  (it's been snowing here the past few days). Thanks for the info, I really appreciate it . I just bought a digital camera at Circuit City on sale (going out of business, guess the economic crisis has a slight silver lineing .) So hopefully I'll be able to post some pictures soon.

15 feet sounds like a good size, I know with my 14 footer it's pretty easy to trailer, but it's still big enough to stretch out a bit and carry a few friends to for company. I'm looking forward to seeing your pictures. Have you found a hull for your boat yet?