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[howyson]

I am busy completing a Vosper rttl, but have dragged out the high speed marine steam engine, (A A Rayman plan no 749), I built over forty years ago. It has rusted slightly but not where it matters. It has not been touched by steam but has been run successfully on compressed air. The cylinder was not cast but totally machined from solid and has not been recessed on the outside for the lagging, (how necessary is this).

I have no experience what so ever with steam and have no idea what size or type of boiler would be required in order to put it through its paces. I have no immediate plans to incorporate into a boat but if it runs OK I might be tempted. I have no access to a workshop now so any additional items, i.e. water trap?, would have to be bought in.

Any help would be greatly appreciated.

Howard

[john s 2]

I know this may be difficult to answer but have you any idea of the bore and stroke? The stroke could be measured by removing the cylinder head as could the bore.Possibly one of the lads also already knows this.These measurements would help in advising on the boiler size.A steam trap is used to catch the oil in the exhaust steam to provent oil polluting the water.The steam can then be vented out of the funnel.John.

[kiwimodeller]

From memory the engine is 3/4" bore by 5/8" stroke but I will double check the plans tomorrow. The original plans include a 4" diameter by 9" long boiler but Alan Rayman later said that was bigger than neccessary and that a 7" by 4 " would have been suuficient I have the 9 x 4 in my 78" long side wheel paddler and it gives me very long run with no problems. The engine may have been designed for high speed use but it is just as happy slogging away in the paddler and will slow down to a gentle tickover without stopping. See if you can P M Steamboat Phil who is very familiar with the engine and the designer. You will be able to buy a suitable boiler from someone like Maccsteam or Cheddar Valley. The main other items you will need besides the boiler will be a lubricator and a throttle valve. It will be possible to get the engine going with commercially available bits and pieces and it will be well worth the trouble, steam is greatr fun! Best of luck, dont forget to take and post photos once you have a hull.  Ian.

[TAG]

Hi
I have a copy of the booklet No9 "High speed marine steam engine" by AA Rayman, pm me if you want me to copy it.
Regards
Tim

[howyson]

Thanks for all the info. I have purchased another set of the plans as the originals are long gone. You're spot on with the bore and stroke.

[ooyah/2]

I am busy completing a Vosper rttl, but have dragged out the high speed marine steam engine, (A A Rayman plan no 749), I built over forty years ago. It has rusted slightly but not where it matters. It has not been touched by steam but has been run successfully on compressed air. The cylinder was not cast but totally machined from solid and has not been recessed on the outside for the lagging, (how necessary is this).

I have no experience what so ever with steam and have no idea what size or type of boiler would be required in order to put it through its paces. I have no immediate plans to incorporate into a boat but if it runs OK I might be tempted. I have no access to a workshop now so any additional items, i.e. water trap?, would have to be bought in.

Any help would be greatly appreciated.

Howard

Howard, By the tone of your post it would appear that you want to use the engine in a boat that goes fast.
Along with the booklet on the engine build Alan gives 2- boilers and in my opinion there is only one that will get a boat going and that is the Scott type boiler.
This can be pressurised to 150 psi and is quite an easy boiler to make but as you say that you don't have any machinery you will have to get some body to make you one.
You will require an engine driven water pump and a fuel tank that can be pressurised with paraffin to 60 psi and a large roaring type burner, all listed in Alans booklet.

Here is are some epics of the Scott boiler and a poppet valve engine that at 150 psi did 10,000 rpm on the bench.
I actually made Alans engine but with a Flash steam coil of 22 ft stainless steel and twin burners of unknown pressure and temperature the valve fussed it's self to the cast iron cylinder face and the piston with Aluminium make up stuck in the bore.

Your question on the engine cylinder , without lagging it will make no great difference to the engine performance.

George.

[howyson]

Thanks very much George. It will need to be a reasonable sized boat to accomodate all that equipment, any suggestions? I still have some way to got on the rttl but it does no harm to plan ahead.

Howard

[ooyah/2]

Howard,
Why not get in touch with the South Shields model boat club.
As far as I am aware they still run steam driven straight runners and you could get some help from them.
You would need a hull in the lines of a patrol boat with a flat transom to allow it to get up on the plane and I think about  50" long.
I am sorry but I can't be more specific as my experience only covers Flash Steamers and a Steam tug.
George.

[howyson]

Not to worry, thanks for all your advice and I will contact the South Shields model boat club.

Howard

[kiwimodeller]

Howard, Models by Design do a 50" Navy Picket Boat hull which would take the Rayman engine very nicely and also has enough room under the stern for the sort of prop you would need to use. They also offer optional boiler room cover and gun mount but you could easily build it with another style of cabin etc. Kingston Mouldings do a 44" Steam Yacht Tender which also has enough bouyancy to take your engine and boiler combo. You could of course put in a tug hull but these two are a bit slimmer and would probably perform a bit better. Hope this helps, Ian.

[John W E]

hi ya Howyson

if you go to South Shields Model Boat Club, Marine Park Lake on a Sunday morning - there are 2 guys there - named John Neilson and Bob Kirtley, I would say they have best knowledge of steam in this area (that I know anyway    )   Bob and John and very easy to talk too - If you wish I can send you a personal message with their telephone number details - aye

aye
john

[howyson]

Thanks Kiwimodeller for the suggestion. I will certainly check it out.

Bluebird, Thanks for the names. I threatened before to come across and see you so even more incentive now. So when I return I will definitely make the trip on the first available Sunday.

Thanks again to all for all the help and information.

Howard