Seamaster 25 - Admiral - Fitting a new 900cc 3
cylinder diesel
Our Seamaster came with a 30 year old 1500 cc Ford Watermotor which was a
pre-crossflow Ford petrol engine from the old Ford Anglia or Mark 1 Cortina.  The
day we collected Kimbo 111 we motored to our new Marina birth only to find a fire
engine  putting out a blaze on the boat 3 moorings down.  This was a Freeman 21
fitted with the same Watermotor which had caught fire while warming up.  Petrol
fumes collect in a boat hull with potentially disastrous results.
Our motor ran well but it was very difficult to start, classic signs of a worn out
cylinder bore and resulting low compression.  I decided to fit a small diesel engine
and I chose a 900cc 3 cylinder diesel from Thorneycroft.  This cost around £3,000
with gearbox and control panel.  Not too bad as a diesel powered boat is worth at
least at least £3,000 more than a petrol.
I transplanted the engine over Christmas 2002, it was freezing and both the
engines were very heavy so I hired an extended forklift.  I then had to fit a bigger
propeller with a course pitch.  I was worried that an 11bhp diesel would not push
the boat along as well as a 25 bhp petrol.  Everyone had reassured me it would be
OK.  In practice the little Thorneycroft was perfect.  I could maintain 2.8 knots on
tickover, 4 mph on very little throttle and 12 mph flat out which was the same top
speed as the Ford engine.  The river Ouse is restricted to no more than 7 mph at
best and 4mph on many stretches.  Our little diesel had no problem coping with
long runs upstream against the current.  A really rewarding project.  The
Thorneycroft used about 1 gallon of untaxed red diesel a day, about 40p,  which
was a bonus.
New control panel
New 12 x 14  
propeller fitted.
Removing the
old one from the
tapered shaft
was very difficult
because I could
not remove the
rudder.
New engine box in the cockpit.
My first attempt at routing and
working with wood stain
If you want to contact me about anything on this site please email me - adrianmol@yahoo.com
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NEW SUB-DOMAINS