Billsteamshovel wrote:....
My rough calculations show it is capable of delivering ample HP to power my boat, based on operating at 125psi and around 500RPM.
....
Wes
Hallo Wes,
please note, that my calculaton was based on 250 rpm. (steam consumption of 170 kg/hr / 375 lbs/hr)
At 500 rpm you will need 340 kg/hr / 750 lbs/hr !!
You could use a boiler from about 50 square feet heat transfer surface area to 100 square feet surface area. In a firetube boiler about 100 square feet, a good water tube boiler about half as much, 50 square feet. These boilers will give about 10 horsepower for easy cruising, and either could be pushed with a vigorous fire to give 15 - 17 horsepower.
At 10 horsepower you will require about 30 pounds per hour coal fuel, or about 60 pounds per hour wood, or about 4 US Gallons of oil per hour. Double those numbers at 17 horsepower.
You have a good, relatively local knowledge base in the Steam Boat Association of Australia, http://www.steamboat.com.au . They put out a quarterly publication, the Steam Leak which is in color and contains good info. Finding and maintaining a good "reference people" data base is the most important part of creating a hobby steamboat. Join an organization or two and don't be afraid to ask people for help. Most of us are pretty friendly and, if nothing else, misery loves company!
My project is still ticking along despite some reasonably ordinary weather - cant wait till the roof is on my cabin.
I'm aiming to have her back in the water, albeit still running her diesel by the end of the year.
I'm also trying to nail down my options for a boiler, with a view to building one next year.
Some of my local steam boaters have been really helpful on this but like all things I'm getting a few different opinions, as also seen on here, so would appreciate your thoughts.
I recently bought the SBA's boiler design library, which has two designs that may be suitable:
1. A horizontal wood fired WTB, number 3 in the Library, which has a heating area of 60 square feet, not counting a super heater.
2. A wood fired locomotive type, Loco 1. The Library doesn't give the heating area but its listed max output is 880lb/400kg per hour - which is in the ball park.
The Library lists 'Pendlebury' has having one of these. The SBA website lists her as running a 3x3 double simple, which produces 7IHP at 400 RPM.
The site lists the boiler as having a heating area of 40 sqft, derived from 47 x 1 1/4 fire tubes of 2ft 2 inches long - I haven't done the maths on this, so it may not be 40 FT.
My concern(s) are that firstly the VFT is too small for my engine. I'm favouring the loco boiler but I'm concerned that its still too small to run my 4x4.
I also really like the idea of a Scotch but as yet haven't been able to find any plans for one that would suit.
Prestons have one that would be just about perfect but its not cheap, needs a significant amount of work and is located on the other side of the world..
Does anybody on here know of or have any plans of such a Scotch?
Hallo Wes,
most locomotive boilers will deliver their power only with enough draft, that means non condensing.
Don't know if this will be right for you.
A locomotive boiler could be lengthened in the tube section, 2 ft 2 in seems anyway very short.
If you have a little bit of patience, I will write in two or three weeks about my last boiler (scotch),
maybe you get some ideas then.
edit: what is your budget for the boiler, if I may ask?
More than happy to wait a bit - not like my boat is going anywhere at the moment..
I had similar thoughts on potential problems with a non condensing loco boiler as my boat operates in salt water, in addition to needing to store lots of wood or coal.
As others have also suggested my preference is for a Scotch boiler. Off the top of my head I could fit one around 1.3m long and around 80cm diameter, with a weight of around 500kg without too much trouble.
I'd be amazed if there wasn't a few members on here with designs for such a boiler.
As for a budget, who knows - but was thinking along the lines of purchasing the steel myself, getting it laser cut and then fabricated professionally - so in the order of 2-5k I guess.
If it were to be much over that it may actually be cheaper to import and restore one.
Wes
You have a good, relatively local knowledge base in the Steam Boat Association of Australia, 
