ComNav P4 - Page 119

ComNav P4 Installation and Operation Getting Started
Document PN 29010100 V1r0 - 119 -
On a P4VS without a Rudder Follower
In this application it is necessary to start by testing how well the boat does small turns,
before testing how well it settles onto a new heading. Also, the optimum Rudder Gain
setting must be found first, before adjusting the Counter Rudder setting.
1. Make a small Heading change (~5°), and observe the turn:
 If it makes an abrupt turn, reduce the Rudder Gain one step.
 If it takes too long to turn, increase the Rudder Gain by one step.
2. Repeat the small change of heading in the same direction, observe the
response, and adjust the Rudder Gain as needed, until the turn is at a safe,
comfortable rate.
3. Repeat the sequence in the other direction. Then repeat in both directions a
couple of times, until you are satisfied.
4. Now make a larger heading change (~10°). Observe how the boat settles in on
each new heading:
 If it approaches the new heading too slowly, increase the Rudder Gain.
 If it keeps “essing” back and forth across the new heading, reduce Rudder Gain.
5. Keep doing turns, and adjusting the Rudder Gain as needed, until the boat settles
in on the new heading, with no more than two overshoots.
6. Now make some 30° heading changes, in both directions.
7. Adjust the Rudder Gain up or down a bit as needed, until the boat settles on the
new heading with no more than two “esses”.
8. Now increase Counter Rudder by 1, and make some 10° heading changes.
9. Repeat this until the boat settles in on the new heading with little or no “essing”.
10. Repeat the steps for a P4VS with an RFU, using gradually larger Course
changes, up to 40°– 50°.
11. Repeat the above adjustments on several different headings until you get
consistently satisfactory results.
12. Reduce the Rudder Gain by 1, then increase speed to your normal cruising
speed, and repeat steps for both P4/P4VS with and without an RFU. If the rudder
is moving by large amounts – more than approximately 5° side to side – during
any of the steps, you should reduce the Rudder Gain even more. You should also
do so if the boat steps up onto plane when you increase speed, because the
rudder’s steering effect is typically much stronger once a boat is planing.
You can leave the higher speed tests for later, if it is not safe to run at that speed where you
are doing your Sea Trials.
Adjust Turn Rate for Hi Speed
1. Adjust the Turn Rate setting to the full comfortable rate (per the previous step 6).
2. In AUTO mode, make a few course changes of 20° or more, to ensure that the
rate of turn is indeed comfortable at normal cruising speed; if it is not, reduce
the Turn Rate setting until it is.