O43: Good tracking on starboard side - poor on port side

[Jochen Vetterlein]

Hello everybody,

I'm an owner of a Oceanis 43 since 2018. I'm really happy with the boat - except with the following situation:

Tracking on the port side is, let's say: poor. Even in ideal wind conditions (12-16 kn wind) the speed is only 5 to 5.5 knots. If there are some waves, you have the feeling, that the boat has not enough power to push through.

On the starboard side, everything is fine: The speed is 1 to 1.5 knots higher, even at higher tracking angles. 

I have this phenomenon since sailing the boat in literally every wind and wave condition. This year I got new sails, which didn't make a difference. I checked it the rigg is proper trimmed - there is nothing to complain.

Is this a common characteristic of the Oceanis 43? Maybe due to fact that the motor, skeg and propeller are not in the centerline, but shifted towards the port side?

I'm happy to hear about your experience.

Jochen

 

[Mike Brown]

I had a 2008 for 10 years and while there could be slight differences in speed between a port and starboard tack I did not see a consistent difference like you mentioned. I do sail a Catalina 425 on a regular basis that initially carried a large flag on the port side. The flag made a difference in airflow over the mainsail. It was taken down because of it. If all your sail settings are the same on both sides I do not understand why you’re having the problem. Have you compared boat speed to GPS speed from side to side? If your speed sensor paddle had an issue it could cause a bad reading. Beyond that I don’t have any other ideas. Good luck

Mike

[Jochen Vetterlein]

Hello Mike,

Thank you for your rapid reply! 

I'm happy to hear that obviously not all Oceanis 43 have this strange behavior of unequal tracking performance starboard/port. The behavior on my boat is not only slightly. It is visible on the log as well as on the GPS - always. Standing at the helm you think that you are sailing two different boats. You don't need so watch any instruments to notice that.

So, it is to find out the difference between your and mine Oceanis 43. Some ideas:

* Did your boat had a shaft drive? (There are a very few Oceanis 43 featuring a sail drive)

* My boat heels in the harbor slightly to port (about 2 degrees). Was your Oceanis swimming upright?

Best greetings

Jochen

[Mike Brown]

Our 43 had a shaft drive. Depending on how much water or fuel that was in her she would sometimes have a very small imbalance. Nothing that would cause her to sail unevenly. Do you have the problem on all points of sail? Is it more on any particular point of sail? Are your Genoa track cars set the same on both sides? When you stand at the base of the mast and look up is the mast straight? Are the shrouds on both sides the same tension? Just looking for any differences that could explain why this happens. 
Mike

[Jochen Vetterlein]

It is only when sailing close-hauled. Unfortunately, this is the only course, where performance really matters.

I‘m going to perform two tests:

- Sailing with genoa only (track cars on the same position). In this case any (unequal) trim of the mast won’t influence the speed.

- In a few weeks the boat will be lifted out of the water. I will measure the position of the keel to check if there is anything unbalanced.

Any other proposals or experience concerning the unbalanced performance starboard/port of a O43 are welcome.

Jochen 

[Mike Brown]

I’d also do a test using only the main. The more testing you do the more likely you’ll find the problem. I’d also check to see how much the leeward shrouds sag during all the tests. Let us know what you find. 
Good luck

Mike

[James Taylor]

Sounds like your rigging may be in need of tuning?????

(Owned B43#19 for 10 years), Sailed from Mass to Tampa to Bahamas with it, great boat, no major issues at all. Boat has flat bottom basically so no need to put rails in water. I found it a very agile/quick yacht at all points of sail.

James

[Jochen Vetterlein]

In the meanwhile, I performed some sailing tests trying to be as impartial as possible.

I was sailing close hauled on the starboard and port side. I used the autopilot steering the boat at 37 degrees to the apparent wind. Apparent wind was 12 to 19 knots with almost no waves.

During sailing I monitored wind speed and boat speed acc. log and acc. GPS.

Before sailing I checked that the mast is exactly upright.

I sailed with genoa only and with genoa + main.

My Results:

When sailing with genoa only, the boat was approximately 1.0 kn faster on the starboard side (6kn vs. 7kn).

When sailing with genoa + main there was little difference (7kn vs. 7kn).

From my understanding, the reason for the different boat speed can be caused either by an unsymetric rig or by a unsymetric underwater hull. If an unsymetric rigg would be the reason, I would expect that there is little effect when sailing with genoa alone. But the test results show the opposite.

The only item of an unsymetric underwater hull is the propeller and skeg that are off-centered. But this should have an effect on all Oceanis 43.

There is one more item: In the harbor my boat is not swimming upright, but is heeling 2 degrees to port. But it is hard for me to imagine that this has such a great impact on the performance.

So - I still do not understand what really happens…

[Mike Brown]

Well at least you’ve narrowed it down to the Genoa. I doubt here’s any issue with the hull or running gear. Nor do I think the slight list you have will have an impact either as many boats have the same based on how full the water and or fuel tanks are. I would try adjusting the Genoa cars to see if you can achieve the same speed on either tack. Watch your telltales and see if you can match performance on either tack. I believe you should be able to do so. And if you do then mark the Genoa cars so you can set them the same after making any changes for sailing g on other points of wind. While all this won’t explain why you see a difference you should be able to achieve equal performance on both tacks. Good luck and keep us posted. 
Mike