CAMS -
The Hobie rudder cam system is pretty easy to deal with if you keep it greased.
Use marine grease, if possible, between the cam and plunger. Anything will do
as a temp lubrication: Suntan lotion, WD-40 or Chap Stick etc. Marine or bearing
grease just stays there longer. Lubricating the system will prevent damage to
the cam and plunger that is caused when the cam gets stuck in the down position.
A tight fit is required between the upper arm and cam (lower casting) when the
rudder is locked down. The rudder should be held firmly against the lower casting.
Any rudder movement, aft from the casting, indicates a miss-adjustment that can
allow the upper arm to disengage from the cam without forcing it to rotate into
the open (unlocked) position.
If the cam sticks in the down position there are several methods to get it
to rotate release. From above and forward of the assembly, lift the upper arm
and rotate it aft and out of the way. Loop a line around the cam… yank
the line to pop the cam open. You can also use the tiller arm to assist this
technique by wrapping the line around the cam, then lowering the tiller arm
and wrapping the line a few times around the tiller arm. Pull up on the tiller
arm which (through the line) levers the cam open. There are several tools that
can also be used. I use a large blade screwdriver that can be inserted into
the side of the cam to leverage it open. There is also a tool (Hobie Part #
83103 / 2003 Catalog page forty eight) that has a small hook that can be used
(by drilling a small hole in the cam to allow it to be inserted) for leverage.
You can also use a small flat blade screw driver to work between the cam and
plunger... force the plunger down to unlock the cam. I find that this works
very well even if the cams are dry and unlubricated.
If the cam is really stuck down, the only tool needed is a small blade screwdriver.
You work the blade between the cam and plunger to force the plunger down and
release the cam. Don't bother with the big screw under the spring they often
are fused in place and the spring does not need to be adjusted but a few times
in the life of the boat.
If the cam keeps getting stuck down, even when greased, there is a miss adjustment
in the upper casting plate (newer boats), the rudder is drilled wrong causing
too much play in the system or it is worn out (too flexible) where it hooks the
upper casting.
A cam plate too far forward can keep the cam from fully locking. A cam plate
too far aft will allow the rudder to slip aft in the lower casting or allow the
upper casting to be raised without pulling the cam open. To adjust the upper
plate, lock the rudder down and hold the rudder firmly against the lower casting
(forward most position). Loosen the upper plate then back it away from the cam
a little. You want to seat the plate tight against the cam (in the fully locked
position) while holding the rudder forward in the lower casting. Ease the plate
forward while wiggling the upper arm up and down just a bit. The idea is to find
the point of deepest insert that the upper plate can get into the cam. That may
mean that the upper casting is not touching the lower casting. Don't force the
plate too far forward as this will begin to force the cam open. When tightening
the plate, be sure the plate doesn't move. I usually tighten with the wrench
handle rotating forward towards the cam to move the plate forward if anything.
RUDDER RAKE -
Rudder rake (forward or aft in the lower casting) changes the helm feel. Weather
helm (pull on the tiller) is caused by the rudder being aft of neutral. Lee
helm is caused by the rudder rake being too far forward. Best adjustment is
to have slight weather helm on all sailing angles. This allows you to hold
the tiller against a slight pull for holding the boat on a stable course.
The boat should round up slowly if you drop the tiller. Lee helm is dangerous
and can cause you to loose control of the boat. Neutral helm can be difficult
as the tiller is pulling and or pushing against you on different sailing angles
and can cause you to have erratic steering.
On older boats, rudder rake is adjusted by re-drilling the rudder blade. Either
the upper casting hole or possibly both. Newer boats use the upper casting
plate (see adjustment under "CAMS" above) and set screw in the lower casting
for rake adjustments. There is a basic rudder rake setting to compare to. You
can also use a drilling template http://www.hobiecat.com/support/tech/rudder.html
For proper rake adjustment you may need to try several settings. Helm feel will
change with different mast rake, sailing angles and sail settings...
Start off with the rudders in the locked down position. Measure down the blade
12” from the bottom of the lower casting. Mark the rudder with a line 2” long
perpendicular to the 12” point. Using a very thin piece of line, starting
at the top of the rudder pin, align the "line" with the rudder pin top to bottom
(on the pins center line / axis) and check where the line intersects the mark
on the rudder. Mark the point where your rudder pin axis crosses the mark you
made 12" down the blade. Measure in from the front of the rudder. A larger measurement
means that the rudder is raked forward more. More forward rake is less weather
helm. Optimally, you should have 1 5/8” to 1 3/4” for a measurement.
To achieve the 1 3/4” number, you might have to re-drill the front hole
on the rudder or file away at the front of the rudder where it hits the casting.
To much forward rake can cause lee helm and THAT is WORSE and even dangerous.
The boats sail better and are safer if the boat rounds up slowly when the tiller
is released.
You can use the above technique to measure and re-drill a blade. Mount the blade
on the lower casting. Make all of the above measurements and set (and hold) the
rudder in the desired rudder rake position. Lock the upper casting onto the rudder
and lower casting. Push the upper assembly up into the cam to seat it tightly
(that holds the rudder in the raked position once the rudder system is fully
set up). Align the tiller arm angle (vertical position) with the rudder assembly
on the opposite side of the boat. You can mark the bolt hole position or drill
right through using the casting as a drill guide. You must hold the upper arm
in position while drilling this way. I angle the drill slightly forward rather
than straight through. This forces the upper casting forward more as the drill
reaches the opposite side of the casting after going through the rudder blade.
If the hole is too far aft, the rudder will slip aft a bit when under sailing
loads.
RUDDER ALIGNMENT -
Check rudder alignment in the direction of travel. Proper rudder alignment
would be 1/8" to 1/4" toe-in on a 14 or 16. This is measured with the rudders
down. Measure leading edge to leading edge and then trailing edge to trailing
edge. The front (toe) should be closer together than the trailing edge. Measure
at about the little hump on the leading edge and straight back from there for
the trailing edge. It is always possible that the rudders are actually mounted
on the reverse hulls. That causes extreme toe-in problems. Look at the upper
casting / arms to be sure they angle in towards the boat's centerline when
the rudders are in alignment with the hulls.