Page 35 – Propeller Protection
This doesn’t really
have much to do with Stirling engines.
But I repeatedly
see propeller shafts being fitted to hulls for Stirling boats
without any
propeller protection.
Boats and
propellers have been around a long time.
Boat building
practice is to protect the propeller and rudder with something
strong.
It’s called a skeg.
It’s to
protect against accident and poor helmsmanship.
Running
aground is to be avoided.
I repeatedly see boats “cut
the corner” around the downstream end of an island.
All
river islands have a sandbank at the downstream end.
Grinding
the propeller into the sand and bending the prop shaft (and
rudder) is to be avoided!
Likewise “bank
crawling”. I know the rules say “keep to the right”.
But do not hug the bank.
Shallow water is full of water
weeds. The propeller will get clogged.
Stay out from the bank
in the main channel. Water that is 8 or 9 feet deep has no
weeds.
When out walking – life is much better
when you stay to the paths.
Don’t walk through the
brambles.
It’s the same with small boats. Stay away
from weeds and shallows
”But weed shedding
propellers are the answer”. No. Helmsmanship is the
answer.
Priority 1 for a Stirling boat propeller is
that it is large and slow – for efficiency.
Scimitar
profiling may help with weeds – but reduces
efficiency.
Interestingly, Kort nozzle users report
that the nozzle prevents debris from fouling the propeller
