HOME Collection A. Thierens & Sons

Thierens Firefly Cabin Cruiser


This boat; made by A. Thierens & Sons, Trafford Park, Manchester; was made in both steam and electric versions. The electric version was called the Electra Cabin Cruiser. This steam version is known as Firefly. It is powered by a modified Mamod Minor 1 engine.

The hull is a contemporary cabin cruiser style with a low profile cabin, part covering the boiler with the funnel passing through the roof. It has a flush deck and a flat bottom, with a simple rudder and an angled stern tube for the propeller.

The boiler and firebox are taken unmodified from the MM1. They are mounted on a plain flat base which also supports the simple engine bracket. The burner that came with the boat as acquired was a standard Mamod three wick type. I don't think this is what was originally supplied because it is a tight fit to manoeuvre into place but is unconstrained when it's in there. The boiler is 1 1/2" diameter x 3 11/16" long. It is fitted with a standard Mamod safety valve and the funnel, which receives the exhaust steam.

The cylinder appears to be the standard early MM1 type with a disk crank/flywheel. The propeller shaft is fixed rigidly to the flywheel and passes through the stern tube to a two bladed propeller - 1 1/4" diameter. The rudder is mounted directly behind the propeller and is connected to a plain tiller on top.

Mechanically, the boat appears to be in fair general condition. The paintwork, however, has been re-done to a mediocre standard. The paint is thin and is flaking on the bottom of the hull. Elsewhere, it has been unevenly applied. The colours, I think, are at least approximately correct. I have repainted the bottom to protect it from the water.

Make Model Made Description Cylinders Cylinder Type
A. Thierens & Sons Firefly(?) Cabin Cruiser c1950? Cabin Cruiser 1 single acting
Piston Diam mm Stroke mm Valve Type Boiler Type Fuel Mechanical Condition
8? 16? Oscillating Cylinder horizontal meths Good
Cosmetic Condition Paintwork Packaging Purchased Purchase cost Additional cost
fair Partly restored
18/3/2013 213