The drum brush gear was superceded by the simpler riveted 'plate' commutator, with coiled copper gauze brushes simply mounted on a pin held in the end-plates. With this change the motor became the 'Supermarine', introduced in 1957 at 6v-12v, and this is the motor illustrated below.
Note the half-empty paxolin bobbins and the removable linkages on the end-plate - these tell you that there is no reversing coil and a double-pole double-throw switch is needed to obtain reverse. This is a later model from the 1970s- you can tell by the plastic end-plates which hide the bearings and hold the lubricating felt.
Taycol Model Marine Electric Motors
Weight: 35 oz
Dimensions: 4" x 4" x 2 3/8"
Input Power (12v): 4.5 amp
Output: 28 mhp (milli HP!)
Fuse at: 10 amp
Later the Supermarine obtained seperate reversing coils - this version was then called the 'Supermarine Special'. Here is an early Supermarine Special, with brass bearing end-plates. The wiring may have changed subtly in other ways - the Special is rated at 9-12v rather than 6-12v...
The Marine motor appears to have been the first large Taycol motor. It had twin coils and a drum-type brush gear, and was made for a short period between about 1954-58. I think it is the rarest of the motors - I only know of two in existence (unless someone can give me better information?).
Incorrectly, this is the motor shown in the artwork for the 1960 KK manual and leaflet illustration of the Supermarine - they seem to have forgotten to change the image, and, I suspect, mixed up some of the specifications with the Standard. It is odd to see it rated at 6v - you would think that the brushgear and wire gauge were perfectly capable of taking the current at 12v.
Note the 90 deg edge of the iron core where it drops through the paxolin bobbins. This is how you can recognise a Marine/Supermarine - the bigger Double has an iron core with an 45 deg angled edge...
Another view of the massive brass and paxolin drum, and associated folded copper sheet brush retainers. These must have been costly to make and fiddly to assemble, with 10 bolts, two springs and split pins, internal spacers and solder tags...