[PUP] Get home engines

[bob Austin]

Expanding on my comment to John Marshall;  there is always a danger of damage
to the main running grear (rudder and prop), including entanglement in nets or
lines.  Having a rudder on the wing engine gives slightly more drag, but if
you have to , or want to, use the wing engine, you have water flow over the
wing rudder for a positive steering, vs poor flow over the main rudder when
using the wing engine.  This gets away from the 8 to 10 degrees (which is
quite a bit) of rudder angle which John mentions.

A true controlable pitch 3 bladed prop is a lot more effecient than any of the
folding props.  (I used folding props in racing sailboats for years, but would
dive on the boat to change out the prop to a three blade for any serious
powering)--the folding props could get the boat out of the slip, and back
(most of the time)--occasionally the props would fail to open in reverse, or
only partly open in foreward.   A good controlable pitch prop is considerably
more expensive, but also much more effecient--and will give a good turn of
speed.

If you are running a 20 KW genset, it is likely that you will have a 40 hp
diesel engiene to power this.  40 hp on the shaft, will certainly give enough
"get home" speed.

On the other hand, the vast majority of work boats have a single screw--and no
thrusters.  They do fine over 99% of the time--but if they break down, there
is usually another vessel near by to tow them home.  As I have said before, I
have never had a diesel engine fail at sea which I could not fix in a few
minutes.  But I have lost a transmission.  Once the transmission is gone,
there is thrust power from the main engine.  Also the wing engine can eaisly
be put to work driving a large DC alternator, and thus regulalry exercised,
providing 110 volt power to the vessel through an Inverter.

Bob Austin