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[ir3]

I am considering a Mountfleet St. Nectan in the near future. I plan on using steam. I have a few choices for engines, one being a Cheddar Proteus Steam Plant and the other a possible Hemmens Max II. John Hemmens indicated that the Max II had no problems with a 30 lb boat with a 70mm prop. A lot of power for the size of the engine. I think the St. Nectan will come out much heavier and require a larger prop. Will either of these engine be suitable for the St. Nectan or must I consider another engine?

Any suggestions would be greatly appreciated,

Thanks

IR3

[southsteyne2]

Here are some notes on your project (http://www.paddleducks.co.uk/smf/index.php?topic=5455.5;wap2 I would advise not to overpower your model as you will consume more steam with little gain in performance for this type of hull
cheers
John

[ir3]

I no longer have the T2GR, a very nice engine. The St. Nectan instructions recommend a 60mm prop so I think the Proteus or the Max II will be sufficient. To acquire a T2GR and reasonable boiler for it would be a bit much and could be too much power.

Cheers,

IR3

[xrad]

Relatively speaking, one nice thing about having a larger bore is the ability to swing a larger prop with less pressure. I can run my mildura(3/4 x 3/4) at about 15 psi, but the prop is only 100mm, so it will turn this quite easily in the water. I can turn it nice and slow or make it spin fast; the mildura would handle a larger prop up to 6 inch diameter....
 
My other steam boat has a Gage TVR1BB which requires about 20-30 psi to run well (1/2 bore), turning an 80mm 4 blade prop no problem,(41inch boat) but too small for your application ...
 
I have an electric 40 inch trawler that uses gear reduction and electric drive spinning a ~50mm prop. The model was too fast until I loaded it with lead. Now it pushes out a big bow wave but is not fast and not easy to handle....you have to plan ahead...which I like because it is closer to scale
 
If you can get your hands on a max H steam plant with water pump, I would go that route as it will easily handle the close to scale prop size...and there is also gear reduction for larger prop if needed.

[ir3]

Thanks for the reply. I do have a line on a Max Hemmens steam plant and hopefully the seller and I can agree on a fair price.

IR3

[xrad]

Hope you get a fair price too. I would assume that the Max II engine alone would be 600-1000 used, and with the whole power plant and pump system, more.......