We are very lucky to be one of the remaining clubs in the country still able to run Internal Combustion engine powered boats. When the lakes in Fairlands Valley were created in the early 1970s, IC engine boats were in the majority, either as racing boats or by using IC engines to power fast scale or semi-scale boats, as by this point electric boats were not developed enough.


There are still a few IC powered scale boats within the club which put in an occasional appearance.  Some of these will use diesel engines, which are no longer readily available due to the decrease in popularity of using diesel engines, which can be harder to set up, with very expensive fuel and less power than glow engines.


Glow fuel engines are these days the most common.  They are available in engine sizes typically from 2.1 to 15cc with sport or racing performance, this being reflected in the price.  Race tuned 15cc glow engines are approaching 10hp, with small high revving 3.5cc engines reaching up to 40,000rpm


Petrol engines are usually used for racing and typically range from 25 to 50cc.


Virtually all IC engine boats are hand-built these days from components available on-line from specialist suppliers, with many people making their own hardware. There are a few Ready To Run (RTR) boats available with petrol engines, but they are large and fast and not advisable for beginners.


If fast IC boats interest you, come to Fairlands Valley on a Sunday morning, see some boats and talk to the drivers.


There are some members' videos of IC boats on the lake.


Also a few videos on SMBC YouTube channel...  SMBC YouTube channel


IC engines provide a method of running fast model boats for a relatively long time, up to 30 mins.  They do, however, need a lot of additional equipment:  Electric starter and battery, fuel and fuel pump, small hand tools, a sturdy boat stand, glow plug heater and after run engine oil.


 Most societies dictate engine noise must not exceed 80db at 10 meters, this is a law that we adhere to at Stevenage.


 Whilst most of what we do at Stevenage with IC boats is just for fun, some of our members travel the country (and one internationally) to race competitively. In the UK there are three main organisations for competitive model boat racing, detailed below.





By far the largest of the racing scenes in the UK, incorporating both national races and iMBRA, the international boat racing body:


FSR-V – Mainly known as multi as this was the first form of racing multiple boats in the UK, these boats race in an M shaped course and are designed to maintain their high speeds through very tight left hand turns in endurance races of 30 minutes, at speeds around 50mph. Characterised by their very low, submerged drive hulls, they run geared glow engines in 3.5, 7.5 and 15cc, and petrol engines in 27 and 35cc.


FSR-H – Outrigger hydroplanes capable of race speeds towards 100mph, racing 4 minute heats in a clockwise oval. Typically built  from thin plywood, these boats weigh very little and the stresses involved on the boat are immense. Driving them is not for the feint of heart!


FSR-O – Fast monohulls typically with shallow hulls, again running in short 8 minute races in an oval course.






The Offshore Model Racing Association, as the name suggests, was formed to race model power boats on the sea. The Association was formed during 1971 and celebrated its 50th year during 2021! The racing sometimes involves the use of Chase Boats that carry the driver and sometimes races are held in harbours where the driver will stand in an elevated position on the quay side. The Chase Boat race held during 2021 was staged at West Bay, near to Bridport in Dorset on the South Coast and the event took place over a 10km course.


OMRA boats tend to be somewhat larger than the normal boats and boats up to 1.45m in length are commonly used in competitions to cope with the rougher water conditions occasionally experienced.


The races are generally held over a 20 minute duration with a 2 minute mill time. The vast majority of boats now tend to use 2 stroke petrol engines however a few people still enter using traditional glow ‘Nitro’ powered engines, and these are catered for in the A and B classes.


The following is a brief explanation of the classes:


  • A- For glow (Nitro) powered boats with engines up to 10cc


  • B- For glow (Nitro) powered boats with engines up to 10.01cc up to 30c.


  • C- Catamaran hulls up to 65inches in length with engines not exceeding 30cc


  • D-  Standard spark ignition engines not exceeding 26cc and a hull length not exceeding 64inches


  • E- Spark ignition engines not exceeding 65cc with unrestricted tuning permissible.   The hull length is unrestricted but shouldn’t be possible to carry a person.


  • X- This class was introduced to encourage people to be experimental with regards the power source however it has become a class dominated by the modern brushless electric motor.


OMRA also incorporates Z Class, the only class in the three organisations using 2.1cc motors. This is by far the easiest and cheapest way into IC racing seeing as a good .12cu engine is several hundred pounds cheaper than other race engines, and the boats tend to only be around 2 feet in length. It has three subclasses – Standard, Modified and Catamarans. Standard boats are unmodified engines, subsurface drive and no carbon fibre. Modified can either be surface or subsurface, carbon or glass hulls, and engines are geared to enable them to turn larger propellers. The Cat class is new for 2019, and is catamarans with loose restrictions – surface drive, geared motors and carbon hulls.



Here's a short video on YouTube about OMRA.





The British Model Power Powerboat Racing Society was formed about 10 years’ ago to promote an annual series of races on inland lakes.  A few club members have competed in this series in recent years.


 BMPRS run a range of classes, boats tend to be similar to that which OMRA races. Classes are sorted by engine size:



 AA    0 – 3.5 cc glow plug

 A    3.51 – 7.5 cc

 B    7.6 – 11.0 cc

 C    11.01 – 50 cc

 D    0 – 50 cc spark ignition (petrol)

 T1 catamarans  0 – 11 cc glow plug

 T2 catamarans     11.1 – 50 cc glow or spark

I.C specific LINKS (This is not a comprehensive list).









copyright 2021 Stevenage Model Boat Club