S/Y Rio Colorado
by John Woodson

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The Steam Yacht Rio Colorado is a 50'x12' (loa) steam powered sternwheeler built by Bob Scripps at Scripps Foundry and Machine in Fredericksburg, Texas. The 'keel was laid' in 1996 and all fabrication and machine work was done there on site. The engines were designed, patterns were built , and the castings were machined and completed all by Scripps .  The boiler is a Dixon and, the duplex steam pump is a Gardner Denver.

There are 2 separate single cylinder engines, one on each side and connected together by the cranks on the paddle wheel shaft set 90 degrees apart. The engines are made of cast iron from Scripps' patterns, with a D slide valve. The engines are 5"x20" bore and stroke with Stevensons link reversing valve gear, and a single crosshead driven boiler feed pump. The engines operate the 7ft diameter paddlewheel at about 20 to 25 turns per minute. The boiler is a Scotch return flu design with initial firing of wood, and major steaming fueled by twin steam atomizing oil burners using diesel. The craft is very stable and gives little sensation of movement when underway.  Speed is estimated at 6-8 mph. The boiler is rated at 42hp @185 psi.  With much reserve steam, the 3 bell chime whistle bellows  a very "melodious thunder" with much authority!

The steam powered genset is a 12v 33 amp  alternator that delivers its power at 1000 rpm.
It powers running lights, deck lights and a spotlight. The engine is similar to a Stuart Sirius and is 1.5 & 1.5 x 1.5 single acting. It was built by Anthony Beaver in England.

It was launched on its home water at Lake Buchanan in the Texas Hill Country in the Spring of 1998.  It is a wonderful, large steam  cruiser. With a few fishing poles, hammocks and a hibachi, one could become a full time "Steam River Rat".......<grin>.

Subject: S/Y RIO COLORADO
From: Robert P. Scripps

Commenced building this 40’ x 12’ x 2 ½’ steel boat 1996, with scow type hull 1/8” plating, 2” x 2” 3/16’ angle iron for ribs spaced 4’ and 1 ½” x 3/16’ strip FFfs running lengthwise, and 1/8” deck plate for deck. 8’ slope forward and 6’ aft on the bottom. Cabin top ¾” marine plywood on square tubing frame. Steering by cables from wheel to tiller shaft, 3 rudders, and a bow rudder for sharper turning monkey rudders would help. 

Dixon horizontal return tube boiler installed 1998 to replace 40-year-old Bryan 100 sq ft water tube boiler. New boiler, 48” x 54” shell, 21” ID furnace, 79 2” tubes, 210 sq ft heating surface, CI grates for solid fuel and 2 Williams type steam atomizing oil burners. Safety valve set at 180 lbs.

The engines are 5” x 20” conventional stern wheel engines with slide valves, castings made by A&A foundry in San Antonio from my patterns. Stevenson reversing with reverse lever in pilothouse besides lever by the engines, with throttle by the engines. The starboard engine has a crosshead driven 1 ¼” x 20” displacement pump taking water through the hull to the boiler. Engines can exhaust through scape pipes and boat also has keel condenser. This consists of two 3” x 2” x 24’ heavy wall tubing welded under the hull that could also act as skids, exhaust goes into these with condensate going into a hot well 
on deck and from there to freshwater tank below deck , boiler feed with ½” high pressure Penberthy injector, also have a 3” x 2” x 3” Gardner Denver Duplex pump, that can pump water from tank into boiler, or from an overboard hose with foot valve for washing deck or fire hose. These pumps are still being made but very expensive, however you can get parts to rebuild these pumps, and that is what I have. There is also a displacement Lubricators on the steam line to each of the engines. 

The boat also has a 12 volt electric system for riding lights and cabin lights and plug for a search lite in pilot house with a 1.5” & 1.5” x 1.5” high speed steam engine built by Anthony Beaver in England direct driving a 33 Amp alternator.

The stern wheel shaft has 2 ½” babited Dodge bearings, wheel 7’ diameter and 6 1/2’ wide with 12 floats. With 120 to 150 lbs steam wheel turns about 25 RPM can get it up to 30 RPM but a lot of vibration. Have never got accurate speed , but around 6 to 8 mph.