Knapp Roller Boat

[Eddy Matthews]

The Knapp Roller Boat has reared it's head many times on Paddleducks over the years, but I've never managed to find any really good photographs or drawings of the vessel...

The two images that are attached are about the best I've found - In the first one, there is obviously some line drawings, so they do exist, but they are of such poor quality that it's impossible to make anything from them....

Can anyone help with better drawings/photographs?

Regards
Eddy

[waldenmodels]

How's this?

Cheers,

Oliver

[waldenmodels]

One more tidbit...the second article is worth reading too. Noone can say the Victorians had no sense of humor

: Oliver

[Eddy Matthews]

That's superb Oliver, thankyou!

Regards
Eddy

[Eddy Matthews]

Okay, now I've had a short time to study the drawings and how the real vessel was supposed to work, I'd be interested in comments on making a working model....

A lot of questions in my mind....

How big was the vessel that was built? Diameter and length? The patent is for a much larger vessel 150 feet in diameter and 750 feet long!

A large mass would have to be attached to the inner cylinder to keep it stationary, cast lead weights?

The patent shows "drag" rudders for steering - which would work (sort of!), but what about steering when going astern?

How big would a model have to be in order to be viable?

How could it be built so that the motor/drive system, radio gear and batteries etc were accessible?

How to make the bearings for the hull so that the outer cylinder can rotate etc?



These are just my initial questions, I'm sure there will be lots more if I decide to go ahead with it, but for now I'm open to sensible comments and suggestions....

Regards
Eddy

[Tug--Kenny]

I watch with interest, Eddie.  My dream since childhood was to have a large Ball about 10 or 20 foot in diameter, inside of which was another close fitting ball fitted with roller bearings. This internal structure would be weighted at the base, so that when floating, would always be upright for the occupants.

Then, when the flood came, it didn't matter about stability as the inside would always right itself. There were no means of propulsion, but at least you might survive until the waters receded.

Your project is similar to these lines in that the occupants were always on self righting floor, albeit slightly unstable.

To answer some of your questions, I have the following comments to your questions.

  cast lead weights? 

probably

How could it be built so that the motor/drive system, radio gear and batteries etc were accessible?

A cover over the side hatch. (as shown with people gazing out of the door).  The drive shaft would be through the centre line to the outside paddle drum. (extra thought ..  differential gearing to the inside drum in reverse!)

"drag" rudders for steering

Rudders on a parallel bar suspended on flex wire, which would reposition by moving under the craft to the other side when the momentum was reversed.

How big would a model have to be in order to be viable?

About three foot wide might be around a scale of 1/32

How to make the bearings for the hull so that the outer cylinder can rotate etc?

Have the roller bearings built into the outer wall of the internal compartment.


I hope you don't mind my ramblings, but I might have a go on one of these myself. If I don't start now, they will never know I really was serious. 

all the best

ken
 

 



 

[waldenmodels]

I believe the vessel that was actually built was 110ft long by 22ft diameter.

[Eddy Matthews]

Hi Ken,

I don't mind your ramblings at all mate, that's the whole point of my posting, to get other peoples comments/suggestions.

Could you elaborate on the differential gearing, and the rudder setup you mentioned? Perhaps with a couple of sketches?

I think 3 foot long would be very small - remember that all the workings, drive motor, batteries, radio gear etc etc all has to fit in the central stationary section which won't be very large in diameter at your proposed size, so it could be a VERY tight fit!

Lets face it, my cigar ship is strange enough, this is just downright weird  

Eddy

[Eddy Matthews]

I believe the vessel that was actually built was 110ft long by 22ft diameter.

Thanks Oliver...

regards
Eddy

[steamboatmodel]

Hi Eddy,
Living in the East end of Toronto Mr Knapp's Roller Boat has always fascinated my, but very little can be found on it even it final location is not known exactly. I have added what I could find. The one thing that I have never been able to figure out was how the steered the dang thing, the drag rudders shown in the US pat. are not shown in any of the photos.
Regards,
Gerald.

[Dinosaursoupman]

Using Oliver's dimensions, at 1/32 scale the Roller Boat would be 41-1/4" in length and 8-1/4" in diameter. That is a lot more room than you have in your Cigar Ship. The catchy part is, using the end on view that is labeled "knapp.gif" I've calculated that the draft of the 1/32 scale model would be only 1-1/4". Your model would have to be very light to meet the prototype's waterline.

I think the tricky part will be trying to minimize drag between the outer shell and the interior workings. I would use small bearings (less surface contact) between the 2 sections. I would use a single bearing mounted in the center or 2 bearings mounted close to the center and mount equipment on either side of the bearing. Equipment and weight will have to be distributed evenly along the axis. You'll have to have a hollow shaft through the bearing/s to allow either mechanical or electronic connections between the different sides.

The rudders are going to present a problem. As designed, they are attached to the interior section of the ship. Water pressure will tend to want to tip the interior section. Depending on how much ballast you'll be using will determine how much of an effect this will have on the interior section. One thought I have on making a simple yet viable rudder system would be to extend the rudders out the sides of the vessel along the axis and have them dip into the water on the side in the direction you want to turn, rather than having them trail behind the boat and rotating into position, as per the patent drawing.

Randy

[Bierjunge]

Using Oliver's dimensions, at 1/32 scale the Roller Boat would be 41-1/4" in length and 8-1/4" in diameter. That is a lot more room than you have in your Cigar Ship. The catchy part is, using the end on view that is labeled "knapp.gif" I've calculated that the draft of the 1/32 scale model would be only 1-1/4". Your model would have to be very light to meet the prototype's waterline.

That's not so light as it seems. Using your dimensions, if I just calculated correctly, the displacement would be some 207 cu.in., the weight therefore some 120 oz or 3.4 kg. Seems quite feasible...

Moritz

[Eddy Matthews]

Thanks for the input guys, greatly appreciated!

Looking at the photos posted by Gerald, it's clear that the vessel as built had a LOT of differences to the patent drawings. The centre stationary hull section is clear throughout it's length, so how was the drive transmitted to the outer hull? There is no sign of a drive shaft running the length of the hull (or is it the beam?). There are no visible rudders, so how was steering accomplished?

My feeling is that a model at approx 1:24 scale would stand a reasonable chance of working - That would give a model with a length of 55", an outer hull diameter of 11" and a displacement of approx 8.165kg (18 Lbs).

I think the larger size would allow more weight to be attached to the bottom of the centre hull to prevent it from trying to rotate when underway.

The centre hull is approx 12 feet in diameter, so that equates to 6" on the model at 1:24 scale - At 1:32 that would only be 4.5" diameter, and would be too small IMHO. The cigar ship is 4.5" diameter, and it's a tight squeeze in there, but at least I have decent access by removing the entire deck - That's not something which could be done easily on the Roller boat!

I'm open to further comments and suggestions....

Eddy

[mjt60a]

....so how was the drive transmitted to the outer hull?...

maybe like on this type of railway - http://dewi.ca/trains/snowdon/pix/b006.jpg - but with the 'track' running around the inside of the hull?

[waldenmodels]

Contemporary descriptions state that the engine ran on a toothed track round and round the inside, "like a squirrel in a cage". Due to the weight of the engine, it stayed pretty much level, as did the platform it sat on, and the outside rotated. You've got to wonder what happened when the vessel ran into an obstacle and the operator didn't disconnect the drive quick enough...

Cheers: Oliver