For the last 30 years, feathering propellers have
been the most
efficient, all-round, drag reducing propeller for sailboats.
The
best known make of feathering propeller is the MaxProp
which has dominated the market
since being introduced
in the 70's and was at this time considered to be state of the
art design. MaxProp
is still sold today in its original form with
some minor modifications, such as
external lubrication.
It was in the late
80's in Solbiate Olona Italy, that two companies;
Cober srl (ltd) -
specialists in CNC technology and Marine Propeller
set out to address what improvements could be made to this older
design of feathering
propeller that had, what were to them; inherent
deficiencies.
Their
objective was to produce a factory "permanently assembled"
feathering propeller using CNC machining technology.
In order to achieve this, the future Jprop would have to meet
the following criteria:
 |
Installation rather than assembly of prop on the shaft. |
|
Pitch
would be externally adjustable and provide a clear base-line |
|
All
components would be CNC machined to tolerance, allowing free |
|
Provide external lubrication. |
|
Designed to reduce wear. |
This resulted in a series of designs and patents,
culminating in a 1993
US patent on which today's J Prop is based.
see US patent 5232345 @ www.uspto.gov
for images relating to above patent click here
Jprop's
design in its present form achieved what it set out to do
with the following
results:
click
for more info
Easy Installation
Externally adjustable pitch (no tools necessary!)
External Lubrication
Advanced design, using aluminum-bronze and
stainless steel components.
Aluminum-bronze having high tensile strength and a
very strong
resistance to galvanic corrosion.
Helical (continually engaged) gears.
Full differentially geared pitch adjustment.
Elliptical blade design assures maximum thrust
in forward and reverse.
Jprop is covered by a three year limited warranty.