US NAVY'S - Incat

from Belfast to Stranraer now takes 119
minutes, an increase of up to 14 minutes
on previous schedules depending on the
time of day.
However, both HSS’s are driven by powerful
gas turbines with a fuel bill far in excess of
Incat’s largest diesel craft – the 112 metre
Wave Piercing Catamaran.
The reduction in HSS speed has seen
consumption drop from approximately
30,000 litres per crossing to around 22,000
litres per crossing from Holyhead - a saving
of 8,000 litres per crossing. However, if
we look at the Incat 112 metre running
at 100% power, which nobody does, we
see that she will burn around 13,000 litres
for the berth-to-berth crossing – that’s an
impressive 9,000 litres less than the speed restricted HSS.
Reduce the engine RPM on the 112 metre vessel to
a more normal 80% MCR and the consumption for a
berth-to-berth crossing at around 34 – 35 knots drops
to approximately 10,500 litres, or around 8.75 litres.
We do not mean to say the HSS concept is flawed,
far from it! However these vessels were designed
in the 1990’s when oil was a fraction of current
prices and were built to operate until at least 2022.
They use more than twice as much fuel as a
conventional ferry, consuming a Marine Gas Oil
similar to kerosene used in jet aircraft and double the
price of standard marine fuel.
But some still claim that diesel high speed ferries
are too costly to run in today’s economic climate.
We think a look at the diesel high speed craft in
historical context is warranted.
This graph shows comparisons in fuel consumption per nautical mile between typical vessels.
All vessels have what is known as hump spped.
Large ships must operate best above hump speed. By operating Incat’s 112m vessels
above hump speed, operators will benefit from the most efficient fuel consumption figures.
T o n n e s p e r n a u t i c a l m i l e
RO RO LIMIT
no go zone
BEST SPEED
FAST SHIPS
5 10 15 20 25 30 35 40 45 50
Speed (knots)
Incat THE Magazine Issue 36 29