|
RUDDER BLADE MEASUREMENT DIAGRAM |
| 1. |
The profile of the rudder blade
shall comply with the diagram. It shall be a fair curve. When
positioned over a template of the maximum and minimum permitted
profiles it shall concurrently be not greater than the maximum
nor smaller than the minimum. |
| 2. |
The datum lines for profile measurement
are:
| (i) |
for width; a straight edge placed
against the trailing edge. |
| (ii) |
for length; a straight edge placed
against the highest point of the blade and at right angles to
the width datum line. |
|
| 3. |
The trailing edge of the blade between
the lower and upper limits of the top and bottom radii respectively,
as shown on the diagram, shall be straight except that concavities
of not more than 2.5mm, which in aggregate are not more than
100mm, are permitted. For measurement of width any such concavities
in the profile shall be bridged. The overall profile shall be
a fair curve. |
| 4. |
The shape of the cross section is
optional except that:
| (i) |
below 85mm from the bottom edge
the thickness shall be not more than 22mm. |
| (ii) |
above a line 85mm below the top
of the centreboard the thickness shall be 20mm ± 2mm.
It shall not vary by more than 1mm except that within 20mm of
each edge the board may be shaped to a thickness of less than
18mm. |
| (iii) |
between the limits in (i) and (ii)
the thickest part of the board in any section shall be 20mm ±
2mm.
If of hollow construction the thickness limits shall not be exceeded
if sub or super atmospheric pressure is applied at the drain
hole by blowing or sucking. |
|
| 5. |
The centre of the pivot hole shall
be not less than 70mm from the top of the blade. |