Unusual sight & sound on Lochcarron
Recently there was an unusual vehicle travelling on the water of Lochcarron. It was a 16 foot
hovercraft. The hovercraft had its maiden voyage on the Loch on Saturday the 12th Dec.
Ironically it was 55 years to the day from when Christopher Cockerall the inventor of the
hovercraft, patented the original hovercraft design.
The hovercraft is a unique vehicle, as it is capable of travelling on land, water, snow & ice.
The hovercraft floats above the surface on a cushion of air contained within its surrounding
skirt. This means that there is no friction between the hovercraft and the surface of whatever
it is travelling over making it capable of operating in areas that are out of bounds to other
types of vehicles. The hovercraft is also capable of floating like a boat, so can be used for
fishing. The hovercraft also has its limitations because of the air cushion on which it travels,
as they don’t work very well on slopes or in strong winds.
The hovercraft in Lochcarron was built by a local ambulance crew member in his spare time.
The hovercraft was built from a set of plans purchased on the internet from a company called
Amphibious Marine based in the USA. Amphibious Marine, owned by Bryan Phillips bought
the manufacturing rights a few years ago of the Sevtec range of hovercrafts, from a man
called Barry Palmer. Barry Palmer was an aeronautical engineer, who back in the 1970’s
designed the Sevtec range of hovercrafts in his spare time. There are seven different
hovercraft in the Sevtec range. These hovercrafts are of various size & can be built using
various engine sizes. The smallest hovercraft in the range is called the Scout, which is 11 feet
long and can be powered by a 12 horsepower lawn mower engine. The largest craft in the
Sevtec range is called the Mariner which can be built up to 28 foot long, carry up to 16 people
and powered by a car engine.
The hovercraft in Lochcarron is a Sevtec Surveyor. This hovercraft design can be built in two
different sizes, which are 14 & 16 foot long. There is very little difference to building costs
between the two sizes. The 16 foot version was opted for as this gave a bigger carrying
capacity, but more importantly more buoyancy making it a safer craft for use in open water.
The Sevtec Surveyor can be fitted with a range of engines. It can be powered by a one or two
engine configuration. With a two engine version, an engine of approximately 12 hp would be
used to supply the lift and another engine of approximately 18hp to 22 hp for driving the
thrust propeller. The Sevtec in Lochcarron is powered by a 35 hp Briggs and Stratton engine.
The 35hp engine drives both the lift fan and the thrust propeller via a series of pulleys and
belts. The lift fan is a 2 foot diameter nine bladed air-conditioning fan, which are readily
available in the UK. The thrust Propeller was Imported from the USA, as there are no
manufacturers of suitable propellers in the UK. The thrust Propeller is a 2 bladed 72 inch
composite aircraft propeller. It is the propeller that gives this hovercraft its distinctive sound
similar to an approaching helicopter. Hovercrafts have had a bad reputation in the past for
being very noisy. This was largely due to the use of high revving 2 stroke engines and
inefficient thrust fans. There is still some work to be done on this hovercraft as regards to
reducing noise levels. During the winter months a new exhaust system will be manufactured
& fitted, which is hoped will reduce noise levels even further. Noise levels are already below
the HCGB acceptable levels.
The hull of the hovercraft was built from a foam cored fibreglass sandwich. This is a very
easy way of building otherwise complex structures. The foam used is not the beaded white
polystyrene type of foam, as this would not be strong enough and polyester resin dissolves it.
The foam used is a high density foam used amongst other things for marine applications.
Unusual sight & sound on Lochcarron
This foam offers exceptional strength for little weight gain. The hull is made up of a lot of
smaller panels which are later bonded together.
To make the hull all the separate panels are measured and drawn onto the foam sheets. They
are then cut out using nothing more than a straight edge and sharp craft knife. Each foam
panel is then fibreglassed on both sides. These panels are then trimmed again to the correct
size & joined together with fibreglass tape.
The skirt is made from vinyl covered polyester as used for making banners. This vinyl
material is easy to obtain, reasonably cheap but more importantly easy to work with and
repair. The skirt looks quite complicated, but when broken down into individual pieces is
again, fairly straight forward to manufacture and fit. The skirt is made from several pieces,
which are then glued together using a special contact adhesive.
The hovercraft was built using all new parts and has taken approximately 14 months to build.
The hull materials, engine, & propeller were the biggest single monetary outlays, but it was
the smaller and seemingly insignificant items that soon sent the cost of the craft over the
initial budget.
This hovercraft is going down to the Isle of Wight in April 2010 to take part in a planned
event to cruise around the island. There may be a similar event held on the North West Coast
of Scotland in the Summer 2010, (subject to correct permissions & insurances being gained).
Hovercrafts are becoming more popular these days. There are basically two types of
hovercraft. There are cruising craft such as the Sevtec range, which are used for exploring &
fishing etc. There are an increasing number of cruising craft in the UK as this form of
hovercrafting is growing in popularity. The other type of hovercraft is the racing craft.
Hovercraft racing is very popular in the Southern half of the UK and Europe, but no
hovercraft racing events are held in Scotland. Racing craft can reach speeds of up to 80mph.
Racing craft are not suitable for use in deep water, as they are built with very little inherent
buoyancy. The 2010 world hovercraft racing championships are to be held in August at
Towcester in the UK.
If you are considering a hovercraft, the first thing you need to do is decide what you will want
to use the hovercraft for, (cruising or racing). Then you need to gather as much information
and advice as you can on the different types of hovercraft & manufacturers. It is possible to
buy new “ready to go” hovercraft from several hovercraft manufacturers in the UK, or there is
the self build option, such as the one in this article.
A good place to find out more about the different forms of hovercrafting is from
The Hovercraft Club of Great Britain. Their website and members have been very helpful
with advice while building the above hovercraft.
HCGB web address: http://www.hovercraft.org.uk/