CHAPTER 12
Armed with the proper rudder, rudder stock,
and bearings, the next considerations are the
rudder-stock angle and control of the rudder:
the steering system. Installed rudder-stock
angle can affect boat trim and performance,
while without a reliable steering system, the
best rudder still won’t point the boat where it
needs to go.
Rudder-Stock Angle and Planing-Boat Rudder Configuration
Fore-and-Aft Rudder-Stock
Angle and Boat Trim
An often overlooked aspect of rudder instal-
lation is the rudder-stock angle. As viewed
from the side, the stock can be dead vertical
or angled either forward or aft. Keep the
following in mind:
- A rudder stock angled/raked aft from
top to bottom depresses the bow when
the rudder is put over. - A rudder stock angled/raked forward
depresses the stern when the rudder is
put over.
Rudder-Stock Angle,
Control, and Installation
Considerations
On contemporary sailboats, it’s not un-
usual to have moderate aft rake to make the
spade rudder more nearly perpendicular to
the swept-up hull bottom aft. A moderate
amount of aft rake is acceptable, but you
should avoid raking rudders aft more than
9 degrees to vertical or forward more than
12 degrees. In fact, there’s usually no reason
for forward rake, except on transom-hung
rudders. Traditional long-keel sailboats often
have forward rake well over 12 degrees, but
this is not best practice and there’s no rea-
son to do this on a modern boat.
On powerboats, rudders should always
be vertical or nearly so.Transverse Rudder-Stock
Angle
On sailboats with twin rudders aft (such as
the Open 60 class), it’s normal to have the
stocks roughly at right angles to the hull
underbody. This splays the rudders out at an
angle to the vertical plane when viewed from
astern. On a wide-sterned sailboat that heels,
this is a good thing. The lee rudder will be
deeply immersed and at closer to vertical
when heeled, and thus more effective on the
wide underbody aft. Such hull forms roll a
single, centerline rudder out of the water to a
large degree when well heeled.