Kingston Mouldings Kingston Mouldings
Kingston Mouldings
Kingston Mouldings













Gun Boat & Tender Hull Length:535mm (21") Beam:165mm (6.5")
Steam Yacht & Launches Hull Length:540mm (21.5") Beam:170mm (6.5")

The MiniVap 50 class for small steam powered R/C model boats around half a metre long originated in France. It has since become popular in many other countries around the World, though in non French-speaking areas, it is more often referred to by the alternative name of Ministeam. These hulls have to be quite full and chunky to take the weight of a miniature steam plant in a model as compact as this. For the same reason, they also need fairly generous freeboard, but this makes them remarkably seaworthy despite their modest size. They are quick and relatively cheap to build, and there are none of those transport and storage problems associated with larger models. The rules are simple, and many clubs run competitions for MiniVaps, the usual aim of which is to steer around a marked course for a set time. Any small steam engine can be used to power them, and our models have been designed around steam plants from Cheddar Models and SVS (Stour Valley Steam Engines). A Cheddar steam plant has been drawn in place in the tender to illustrate the layout of a MiniVap model more clearly. Steam isn’t compulsory of course, unless you want to take part in Ministeam competitions, and the hulls are just as suitable for any small electric motors that you may have lying around. Sadly, production of both Cheddar and SVS engines ended some time ago, and the choice of small new steam units has become rather limited, at least here in the UK. However, a good steam engine only gets better with age if properly cared for, and there is a fairly steady supply of secondhand examples of both Cheddar and SVS engines offered for sale in the small ads in UK model magazines such as Marine Modelling and Model Boats. The top photo opposite shows a Ministeam event in Japan, every single model was built on a Kingston Mouldings Steam Launch hull. The second shows two of my own models under construction, you'll find a well illustrated feature describing the construction of these models elsewhere on the site. The next pic shows the prototype Cheddar powered Tender, followed by Cheddar Models own Steam Launch demo model. Following pics show my own Steam Yacht and Gunboat, and that Open Launch was featured in the French magazine RC Marine, constructed by Piérre Deberne with an appropriately dressed Gallic occupant on board. The final two pics show my electric powered Tugboat.


The Tender was the first of our MiniVap/Ministeam hulls, and it measures 535mm long by 165mm beam. The hull is roomy enough to make fitting out relatively easy for this class of model, and it has plenty of reserve buoyancy. It is also stable, and handles like a dream. Cheddar Models ran one of these as a demo model for their Kompact steam plant, which can be seen in the cutaway view, and the Cheddar demonstration model is the one shown in the photos below. Other examples built by our customers are performing well in Ministeam competitions, mostly with Cheddar and SVS power units, but also with some other small steam units, and a considerable number have also been built with electric power.

These two launches are 540mm long by 170mm beam, and so far they have been the most popular designs in the Ministeam range. Many examples of both these launches and the Steam Yacht have been sailed successfully with Cheddar Kompact steam plants, including some of Cheddar’s own demonstration models. Although the combination performs well, the powerful Kompact plant is one of the heavier units that can be fitted in MiniVap models, so even if the weight the rest of the model is kept down, low freeboard can restrict this pairing to calmer conditions than some other hull/steam plant combinations can cope with. To overcome the problem, a modified version of the launch hull with greater freeboard is also available at no extra charge. Just over 6mm has been added at the stern, and around 10mm amidships, tapering away to nothing at the bows.

The Steam Yacht measures 540mm by 170mm, well within the limits specified in the Ministeam rules, and it is a modified version of the Steam Launch hull. The hull is slightly more tapered at the ends than the Tender/Gunboat/Tugboat, which can make it a little more of a squeeze to fit everything in, though as with the steam launch, a slightly deeper version of this hull is also available at the same price, to give added freeboard for heavier steam plants or less sheltered waters. The deeper version has just over 6mm added at the stern, and around 10mm amidships, tapering away to nothing at the bows. However, our own test model performs brilliantly with an SVS steam plant in one of the standard lower freeboard hulls, being very seaworthy and not appearing at all overloaded.

The Gunboat is 535mm by 165mm, and the hull form is a slightly modified version of the original Ministeam Tender, which means that it is quite spacious inside for such a small model. The bow on this one has been raised slightly, something that helps a little with seaworthiness when there are any waves to contend with on the boating lake. The prototype model in the photo is fitted with a Cheddar Kompact steam plant, and the hull carries this weight with no problem at all, racing around like a small grey speedboat.

The Tugboat measures 520mm by 170mm. Once again, the basic hull form is a modified version of the original Tender, but the Tugboat has an increased displacement with a slightly fuller and blunter shape at the bow, and bulwarks that lean in all around the hull above the moulded rubbing strip, to give that typical tugboat shape.

It’s also fun and quite easy to come up with your own designs using any of these little Ministeam hulls as a basis, and remember that every one of them is just as suitable for electric power. The Kingston Mouldings home fleet currently contains a Cheddar Kompact powered Gunboat, an S.V.S. powered Steam Yacht, both steam powered of course, and they have recently been joined by a Tugboat with a 4.5v Monoperm electric motor. I’d have to admit that in most respects, this is a much more practical model than the steam powered ones, at least for everyday fun sailing. Steam has a very special appeal of it’s own, but with the electric model, all you have to do is just switch on and go, as long as you’ve remembered to charge all the batteries of course.