"Evan Gatehouse2" wrote in message
...
Jets (be they axial like real waterjets or centrifugal like a bilge pump)
are more efficient than larger diameter propellers ONLY when the boat is
moving fast enough that the drag from propeller strut/shaft/and rudder
becomes a significant part of the drag values.

In the real world that works out to be around 25-30 knots. A bilge pump
will never beat a small trolling motor propeller at displacement speeds.

I've seen Cal 20's pushed by a big trolling motor for a sailing school.
Works o.k. in calm water but in any sort of breeze it's not enough thrust.
The Cal 20 with a 3.5 HP outboard was a LOT faster and would end up towing
the ones with a trolling motor.

For a Thunderbird, a typical 5-8 HP long shaft outboard is the only
solution that makes sense.

Evan Gatehouse

hi Evan,
there may have been some crossed wires here.... the bilge pump/trolling
motor solution was for a 14 foot beach cat.

Shaun