Cylinders for Small Stern Wheeler

[SL Ethel]

So I'm taking the plunge into a 2nd boat - this one to be a small stern wheeler built on an existing 15' fiberglass outboard hull. I'd like to make up engines similar to the one Cliff Blackstraffe described in the old "Steamboats and Modern Steam Launches". He used "No-Pak" cylinders for his design, which he described as being tie-rod type cylinders available in pretty much any dimensions, and suitable for steam or air.

I haven't been able to find any such cylinders. I don't know if pneumatic cylinders might serve, but I can't find any in brass in the 2x12 or 2x16 range. I was thinking about hydraulic cylinders - maybe with a new, smaller diameter piston rod and packing gland.

Does anyone know if "No-Pak" or their equivalent are still around, or have any experience re-purposing other types of cylinders for stern wheel engines? If I have to go the patterns-and-castings route, I'll never get it done.

Thanks,
Scott

[fredrosse]

Make piston/piston rod assemblies from hydraulic and air cylinders. 3.25 inch industrial hydraulic cylinder being used for steam, had a big (1-1/4 inch diameter piston rod, way too big), but I only needed 5/8 dia rod. Drill big piston, then machine piston from a smaller cylinder with 5/8 rod. Press together and lock with "poor boy" keys.

The cylinders are available with hard chrome rods and hard chrome cylinder bores, much better than I can make in my shop, and only a few dollars on e-bay. This piston & rod has been in service for four years now, have never re-packed stuffing box, good allignment plus the hard chrome makes for a long lasting setup.

Get the manufacturer's catalogues online, so you can see how model numbers describe the cylinder's fearures (I got 3-1/4 inch hydraulic cylinder with special industrial hi-temp iron stepped rings rather than elastomeric piston seals). Then troll on ebay, what you want will eventually show up, at 10% of the price for a new retail cylinder.

[marinesteam]

Google "nfpa hydraulic cylinder" and you should find what you are looking for

Or look at http://www.nopak.com/index.html for NoPack website

Ken

[SL Ethel]

Thank you both for the responses - thanks especially Fred for the step by step and pictures.

And I'm a little embarrassed that I missed finding No-Pak last time I looked. Depending on cost, they do look like they would work right out of the box.

I've already got a pile of small hydraulic cylinders for parts, so I'm probably only a few pieces shy of the full kit I'd need to make my own from standard cheap hydraulic parts.

Thanks

Scott

[artemis]

Contact Peter Carlich at Reliable Steam Engine. His email is: carlich@pioneer.net - his website at http://www.reliablesteam.com doesn't show them yet, but he has access to the castings for the engines that Al Dunlap put together for the Cheng Tze. They 3.25" bore x 20" stroke. His castings, etc. are of good quality.