Hull Attitude changes

[lomdel]

Can someone please explain in detail how to achieve a Normal, Wet and Performance hull attitude, referring to the FeCalc table for a Cat. Should the strut be high or low for which attitude? Everyone I ask give me a different answer...

[Ub Hauled]

Wet Hull = dragging the transom
Normal = regular setup (not too wet nor lose)
Performance = Really nicely setup (AKA lose in the water)

[ReddyWatts]

It is determined by how much of the hull is running on the water.

Performance is when only the back pad is contacting the water and running a little loose for max speed. This creates the least amount of drag.
Normal is with more of the hull contacting the water for a good conservative setup for the best speed and control.
Wet is with alot of the hull touching the water and creates more drag.

I usually leave this setting at normal in FeCalc for comparing setups.

This all effects motor amps, watts and speed by changing your COG, rudder and strut angle.

[DISAR]

The attidude also depends on the centre of gravity and I can uderstand that bringing the COG aft you get a "performance" and bringing the cog fwd you get a "Normal", depending on your setup.
Regarding your specific question for the strut I read in the forum that it should be 1/4, 3/16" above bottom. But guess what, i don't know why!

[DISAR]

In addition, positive angle of the strut pushes transom down and lifts the bow hence you get "performance" The following are taken from the supervee 27 manual. Although it is a mono I believe that the principles are same:

Positive angle: Positive strut angle causes the bow (front) to
run high making the boat faster but less stable and likely to
blow off course or crash in rough water. This also places the
least amount of stress on the motor and speed control.

Neutral or no angle: Good for most setups, but ultimately the
prop, weight of the boat and water conditions will determine
if you are going to run your boat with Neutral strut angle.

Negative angle: Negative strut angle can cause the boat to run
tight. Remember, make small adjustments at a time as
negative strut angle places the most amount of stress on the
drive components. Too much negative angle and your boat
might “stuff” dive under water if it comes off a wave.

[ReddyWatts]

IMO, raising the strut, unloads the prop allowing more rpm that gives more top end speed in a cat.

[detox]

I copied this from the UL-1 manual

STRUT – The strut on your UL-1 can be adjusted up and
down as well as tilted. To adjust the strut you are going to
need to loosen the 4mm bolt that holds the strut in position.
When making a strut adjustments you only need to move it a
small amount at a time.
Lowering the strut helps stabilize the boat by lowering the
nose of the boat. However, doing so can slow the boat down.
Raising the strut has the opposite effect. Tilting the strut is
helpful to tune the hull to a particular propeller. If your prop
is causing the back of the boat to hop up and down (unhook)
try removing or lessening the drive angle. If the boat seems
pined (stuck to the water in the back) try adding some drive
angle. I like to adjust the strut to the point the back of the
boat just starts to hop and then move the strut back just a
small amount to stop it.

RUDDER – You can tilt the rudder fore and aft to change the
way the boat handles. The more you tuck the rudder under
the boat (negative angle), the tighter the boat runs on the
water. Tilting it back (positive angle) causes the back of the
boat to run looser. You don’t want to overdo it so just work
within the amount of movement provided by the bolts. Also
the more you tilt the rudder back the less aggressive the
steering becomes.

Here's that dude named Manual Labor:

http://manuals.hobbico.com/aqu/aqub20-manual.pdf

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