1998 Osprey 175 leaning to port side

[MPKehoe09]

I just bought my first Aquasport this part weekend, a 1998 Osprey 175. I put her in the water the first time the other day, and she idled out of the marina fine. Once I throttled up, I noticed that the boat was listing (leaning) towards the port side.

All the weight on the boat seemed to be evenly distributed and I had a dry bilge. The battery is centered under the console, and the temporary fuel cell i was using was also centered behind the cooler seat.

After hauling the boat back out of the water, and rinsing her down, I noticed that the trim tab anode beneath the cavitation plate was angled about 30-45 degrees in one direction. I then remembered that the previous owner also had a 10hp kicker on a starboard side bracket. Do you think he had the tab anode rotated to offset the weight of the kicker? Is that small tab anode really substantial enough to change the way an 1850lb hull rides under power?

I went ahead and straightened it, but haven't had the chance to give it a sea trial. Since then, I've read on some forums that the tab is often rotated to offset the torque of the motor (in my case a 115hp with SS Lazer prop).

Do I have a bigger issue that I have yet to uncover? Or is the roared trim tab anode likely the culprit?

Thanks in advance!
Mike

[Blue Agave]

Does it list when at the dock or at idle?  Or only on plane?  If only occurring on plane you may have a "hook"'in the hull. A hook can develop on the bottom of the hull if the trailer is not set up properly. I would recommend a set of trim tabs.

[CLM65]

As nando said, you may have a hook in the hull.  To check for this, hold a straight edge (2x4, long level, or any other straight object about 5' or so long) against the bottom of the boat, parallel to the keel, with one end at the transom.  If you have a hook, you will have a gap between the board and the hull.  You can slide the board from the keel up towards the chine to check the whole surface area.

But I will also say that I have never seen a trim tab anode turned 30-45 degrees.  That seems like an awful lot, and may very well cause your boat to lean at speed.  But I would also expect it to affect your steering too.  Did it like turning in one direction more than the other?

Oh, and congrats on your first AS purchase!

[FreasFlatFoto]

I have the same problem with the leaning to port, except I dont have trim tabs.  The only weight on the port side is the oil reservoir which is aft on the port side. 

[MPKehoe09]

So after I gave the boat a test run with the trim anode straightened, but now the boat doesn't hold a straight course. When I held the wheel to try and keep a straight heading, it felt like I'm "side-slipping" is that makes any sense. Similar to a sailboat without a keep/dagger board down all the way; will drift sideways as it's making forward progress.

I know this is due to the torque of the motor, and it seems that the only way to keep my heading straight, is to rotate the tab anode, which causes the boat to list.

If I were to install the self-leveling trim tabs, will this help resolve this listing issue? I do not have the budget, nor desire to put $600 actuator/hydraulic trim tabs on a 20yr old boat.

I guess the concept behind the self-leveling tabs, is based on the amount of water pressure, the spring loaded arm adjusts the tabs position. I hear these work great for preventing proposing/chine walking/ and getting on a plane quicker, but I don't know if they will resolve my issue.

Any thoughts?

Thanks for any feedback.

- Mike

[Capt. Bob]

Let's take this a step at a time.

First, your hull lists to port under power(prior to relocating the tab).

Second, you straightened the tab. Is it safe to assume it is currently positioned parallel to the ventilation plate?
If so, when underway, did the hull still list to port?

Third, is the boat steering to starboard (you counter by steering to port)?

Now, I doubt the tab is causing the list but to prove that, you will need to rotate the tab in the direction of the "side slip". You need to do this in small increments to find the sweet spot (where the boat holds course with minimal effort). At the same time, you need to play with the trim adjustment on the motor itself. The tab should be adjusted in the least amount needed while the motor is trimmed in its best running position. Both will affect the steering of the boat.

As to fixed trim tabs, I have no experience with them. I do have a port list (due to hull hook) on my WAC that is corrected by my adjustable trim tabs. Hopefully someone here is/has used them will comment.

Good luck.

[MPKehoe09]

Yes, under power the boat lists to the port side (with the tab in its original position).

After rotating the tab (so it is parallel to the vent. plate), the boat no longer lists to the port side under power.
However, it steers to the starboard side.

If I slightly over steer to the port side, and do not let go of the wheel, the boat will hold a straight heading, but feels like it is "side slipping" or drifting to the starboard side.
The moment I let go of the wheel, it cuts to the starboard side pretty drastically.

I need to do some more sea trials to, but I took off my transom mounted swim platform (which was mounted on the port side) because I thought it could be creating drag, and adding to the problem.

I unfortunately now have a couple screw holes below the waterline that I need to fill with Marine-Tex. Unfortunately, I don't see any temperatures above 55 degrees (for a 24hr time frame) in my forecast for at least another week or two. I will have to wait till the holes are plugged and cured before I can drop her back in the water.