An inboard engine was an option first shown in the 1973 brochure although no details of the engine to be fitted are mentioned. However, an article in Yachting World suggests that it was a Stuart Turner "R3MC" and photographs of boats with inboard engines seem to confirm this.
There is some doubt whether Moore ever built a boat with an inboard engine. To date only three boats have been found with inboard engines and all of these are Reedcraft boats. There is also doubt whether the only engine fitted was the R3MC, since one of these three boats has an engine with some distinct differences from the other two. If either of these is the R3MC is not yet known.
Two of the boats have an engine cover like that seen on Hakuna Matata (above and below)
The engine cover on a third example (below) has has none of the bumps of the other two and the location of ancillaries, such as its petrol tank, appear changed as well.
Looking at the two engines, it can be seen that there are a range of differences. The exhaust fitted to Hakuna Matata has a distinct upswept U-bend that accounts for the need for a raised section to the engine cover. The spark plug of this engine enters the cylinder head on the side and the carburettor is different.
While the general design is very similar, the most notable difference between the engines must be that "Sisters" has an electric start, indicated by the battery, starter motor and belt drive to the main crankshaft, whereas on Hakuna Matata you see a starting handle on the shaft.
In both Hakuna Matata and Scorpio the petrol tank is contained in the starboard cockpit locker.The propeller is a simple fixed three bladed design, as one might expect from this vintage of engine.
The brochure suggests a 4hp long shaft outboard engine is ideal, although Reedcraft are known to have supplied a 3.5hp Yahama two stroke engine on their initiative to one customer in 1973. There is little reason to dispute the 4hp recommendation, certainly for boats used in coastal waters. However, a number of inland owners find a modern 2hp engine more than adequate for use on lakes and rivers. Indeed those who use their engine only for exit from and access to their mooring are very happy with modern electric outboard engines.