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S/S Martha

Posted: Wed Mar 08, 2017 9:26 pm
by Lars Hansen
Hello steamboaters!

Time to give an introduction to my steam boat project which have been going on since 2008(!) At that time I would defenitely have thought it would have been finished by now - but that is possibly a story most of you can recognise.

The text below is largely a copy of what is written in the SBA boat register*. If you have any comments or questions plase feel free. I am also most willing to share my drawings and calculations if anyone should be interested.

*For now you will have to see pictures in the SBA register (Search for "Martha") as I couldn't get the "Upload attachment" function to work...

Regards Lars Hansen

History:
The project began in August 2008 where I went to Sweden to visit Bernt Breding and Lars Quist to pick up my new 18 foot glass fiber hull - just the hull I wanted after having seen Pauline (German, can be found in Rainer Radows steam boat register) owned by Hubert Paulus at the steam boat festival in Vejle, Denmark, in 2006. My father and I drove some 800 km to Forsvik in Sweden, a nice spot at the Göta Canal, to pick up the boat at Bredings workshop. We returned with the valuable load of a future steamboat on the trailer. In August 2015 another trip was made to visit Breding in Forsvik. This time to pick up the pressure part of a new boiler I had purchased for the boat. Other good stuff was included in the deal such as a very nice Mollerups mechanical lubricator to supply cylinder oil for the engine. Currently (March 2017) the project is estimated to be 65% complete.

Calc's shows a hull speed of around 5 knots with a 19,5x31" propeller with DAR 0,35 at 300 RPM corresponding to a power requirement of 2,1 BHP. At 4 knots hull speed and 230 RPM power consumption is 1 BHP. I have used the articles by John King in Funnel and got the results verified by the propeller manufacturer BT marine propellers, UK.

Hull:
Open Launch. Construction of GRP and wood.
Hull model: Qviding designed by Bernt Breding and Lars Quist at Sweden
LOA: 18' 0", Beam: 5' 4", Draft: 2' 0", Displacement: 1800 lbs.

Boiler:
Designed and pressure part built in 2015 by B2 Ånga at Forsvik, Sweden
Fuel: Coal. Max. pressure: 130 psi. Heating surface (wetted): 18 sqft. Steam output: 90 lbs/hr.
Main dimensions: 20" dia X 31" high steel barrel. 68 X 0.8" dia steel tubes.
Keel condensing. Engine driven FW pump. Hand FW pump. Injector.

Engine:
Compound of own construction. Cyl. dimensions: 2.5" + 4" X 3"
Piston valve on HP, slide valve on LP. SLRG valve gear.
Power: 2.6 IHP / 2,1 BHP (calculated - to be verified)

Engine currently under construction. Cylinder block supported by six turned columns. Stuart 6A cylinder casting. Engine is 4 inch higher than Stuarts original design. Vacuum pump directly crosshead driven. Feed water pump driven from crankshaft by a cogwheel gearing 1:2. The engine design estimates 2,6 IHP / 2,1 BHP @ 300 RPM and 120 PSI steam pressure. Mechanical efficiency estimated to 80%. Estimatet steam consumption is 35 kg/hr at 300 RPM

Propeller:
Bronze, 3 blades, Right Hand, 19.5" X 31", DAR: 0,35
Shaft: 1,25" Stainless Steel

Re: S/S Martha

Posted: Wed Mar 08, 2017 11:03 pm
by ron parola
Welcome, glad to have you. Hope it all works out to your liking and hope you will be in the water, the boat that is, soon. Winter here is just about over and we had our first ride of the year last week. It really is a most enjoyable hobby and can be QUITE frustrating at times. Now I'm off the the SBA registry to have a look Cheers ronp

Re: S/S Martha

Posted: Thu Mar 09, 2017 9:24 pm
by TahoeSteam
Welcome to the forum Lars. Your launch sounds very well thought out, leaving no stone un-turned.

I too am off to view the SBA register...

EDIT: Just checked out the registry http://www.steamboatassociation.org.uk/page-1117882 and I am impressed! She is beautiful! I can't wait to see her completed.

For future reference posting photos on here is easiest if you use a 3rd-party photo hosting website like www.flikr.com or www.photobucket.com

Re: S/S Martha

Posted: Sat Mar 11, 2017 12:00 pm
by Lars Hansen
Thanks gents! I'll keep you posted on the progress.
Nice boats you have - and good videoes! It's nice to get some inspiration.

Regards Lars