TEAR DOWN
ANALYSIS WITH PHOTO's:
December
2007
In
mid 2007 Mr Poulie of Holland departed in Pas de Deux for a major
trip best documented
on their own extensive web page www.pddeux.nl
His vessel is powered with a
Volvo 2003 Saildrive - We supplied a 16" unit with tip
angle of
16 degrees equating to a normal pitch of ~14"
To obtain an adequate
translation use the following site:
www.freetranslation.com/web.htm
made his SDC unit easily the the high time unit in terms of hours of
use - particularly motoring
and reversing functions.
In Florida
the vessel was hauled for a month as they returned to Holland for Xmas
holidays,
and they very kindly returned the SDC unit for analysis to be replaced
with another identical
unit incorporating all current design modifications. These are small
but not insignificant.
The
results of this usage on the unit are best documented in a series of
photo's taken with
the return of the unit to New Zealand.
BLADE
MOUNTING & DRIVE:
This
shows the broken return spring under the bolt cover caused by the tail
breaking off.
This occurred on both blades and is a problem previously addressed
with a new spring tail design.
This
change is documented under Beta Tests above.
Cover
removed showing spring - minus the terminating leg.
The
following two photo's show the Vectran and wear patterns under the
mounting bolt on both blades.
This portion of the Vectran does not move relative to it's mounting and
is simply a termination using
in effect a riding turn followed by a splice by inserting the tapered
tail into the braid.
The upper
surface rubs against the PETP washer.
The following shots show the Vectran portion that exits the body of the
unit and runs under the grooved blade root.
The two shots show the opposite blades.
Note also
that in each case there is no damage whatsoever to the area around the
mounting bolts that pull down on the face of the body.
The Loctite required heat before the bolts could be removed even after
the removal of the locking pins.
This shots shows the Vectran loop ex the blade base after it has been
removed from the blade.
While it
has necked down to minimum diameter at the relatively sharp corner
where it exits the blade, there is no evidence of
any fibre breakdown. The other side of the braid was as
installed. See lower photo.
BLADES:
This shows
the minimal blade damage to the leading edge of one blade. The other
blade was undamaged.
Note the expected loss of
small amounts of ablative anti-fouling on
high velocity parts of the blade.
BODY OF UNIT:
This shows
the cracking around one of the locking screws between the front cover
and the body.
It is possible this was caused by cross threading or over tightening as
if it was caused by rotational forces
one could expect similar damage on all three locking screws.
This shows
the damage on the next screw - the third was undamaged.
This shows
the Vectran and extensive grease retention still in the unit.
Here the
Vectran has been fully exposed by removing the boss.
BOSS:
This
shows the boss minus the Vectran.
This shows
the small level of wear on the high stress point of the Vectran - but
only on
one side.
Taken in
the body of the unit showing virtually no wear on the Vectran where it
exits the body as the blades open.
The blades are open so the wear section is exposed.
Note there appears to be no damage to this face or splines.
This shows
the rear of the boss with no damage or cracking around the splines or
moutning holes for the locking split pin.
FRONT
COVER:
This shows
the front face of the fornt cover in an as new condition.
This shows
the rear face that holds the exterior of the boss - again in an as new
condition after removal of the grease.
A view of
the front face with no damage to the tightening holes or locking screw
threads.
