Loss of balance - what's the problem?

[Ananda]

Well folks... we took Honu out for her maiden (to us) voyage Sunday on the Columbia River. It was great except for one thing... Something came up I'd like your input on. Has anybody experienced this?

We were going along at a nice clip (90hp Honda) with smooth water under the hull, trim tabs balancing the boat evenly. The 8hp Honda kicker was tilted up out of the water just fine. But as soon as one of us moved at all, steering became very difficult and the boat would lean and veer to one side, forcing me to slow down for safety. Before I slowed, I could see that the prop end of the kicker, though tilted all the way up, was occasionally hitting the water, especially if someone moved. Now, I've spent enough time on canoes to know that, if the stern paddler puts even just the tip of a paddle in the water, you change direction. Is this what was happening? Or do the trim tabs lift you so far out of the water that any movement on the boat has an extreme effect? There were only two of us aboard and the weight was balanced well. I did note that the port fuel tank was a lot more full than the starboard, so I did have to adjust the trim tabs to accommodate that weight difference.

I've been on fast boats and slow boats all my life and have never experienced anything like this. It made me feel wary of using the trim tabs because the sense of "skidding" was a bit overwhelming. It doesn't make sense that the C-Dory, by all accounts a stable boat, should react this way.

If any of you have experience with this, I'd really appreciate hearing from you. The Columbia River is a bit too powerful to feel like you don't have control of the boat at all times. Trim tab problem? Kicker problem? Some other reason for the boat not being stable at 15-16mph? What do you think?

[lloyds]

I doubt the kicker would cause the problem unless it was "extremely" in the water. Just the skeg and the occasional dip of a prop blade wouldn't cause it. Sounds like the trim tabs were trimmed down quite a bit. When you change the weight position one comes up and one goes further down. Just a guess.

[ramos]

I agree. With trim tabs and a hydrofoil it would not be too hard to over trim. With the bow trimmed too far down and the stern feeling light, a clockwise turning prop will want to pivot the boat clockwise around the bow. Can happen quickly and make it almost impossible to turn the other direction. This happened to me as a new C-dory pilot a couple of times. Really had me concerned until I figured it out and began to find the fore-aft balance of the boat. Our boat is much shorter, but has the same type of hull configuration. My boating background includes power and sailboats from 15' to 42', over 21 years. The C-dory deffinately is unique to anything I have run before. I can tell you after 35 hours on this boat I'am amazed at the change in my comfort level with our C-squirt. I believe using your' good judgement you will be very happy with Honu's handling after a few more hours. The boat will tell you what she needs and you will respond accordingly. Stay loose, stay safe, and enjoy!

[Fishhawk]

Kathleen,

I don't doubt you have any problems with your boat. You are going through a learning curve getting your boat figured out. A 22 is light enough so that you will experience the "unstable" feeling when you have weight shifts occurring when underway, especially near that speed. Either slower or faster it might not seem so intense. Trim tabs are a great way to keep things on an even keel but can exacerbate things when you have weight shifts. Drag from a kicker will do that as well. Keep your crew in one place if it bothers you too much.

You'll get it all figured out.

Just have fun doing it.

Capt Dan

[Sneaks]

Also agree with the trim tabs too far down. For all it's charm, the C-Dory is a snooty little craft in the water. It likes to keep it's nose in the air. Overtrim it too much and you can rapidly find yourself in an almost out of control squirrelly situation that gets worse if you hit chop..

Don

[ghone]

I noticed a similar problem my first few hours in the 19. The boat really settled down when I had my cruising gear aboard. I travel light but a few hundred pounds of anchors, water, chain, blankets, pillows etc and such make her really stable. That said, it pays to keep your boat trimmed side to side by moveable stuff and if you are lifting a side due to list with your tabs back them off as the speed comes up as the tabs generate a lot of lift at high speed.

In our third ride last year.. I carved a turn at 28 knots with wide open throttle with my bride hanging onto her handle on the high side yelling "what the h... are you doing!" as I was trying to pull the power off and retract tabs at the same time. My input on the wheel not having kept us straight .It had been fine at 15 but not so good wide open.

Lesson learned, go easy on the tabs while making the jump to hyperspace young Skywalker. .

I found now I rarely use the tabs as I have the Stingray xrIII hydrofoil and use 5 gallon water bags to toss from side to side for trim. On your run with fuel one tank full and one almost empty is a lot of weight. What you are seeing is just the effect of a pretty flat bottom and changing lift at different speeds. I have found with a heavy crew member I can use the tab to lift the port side with tabs almost all the way down (2/3) at 15 knots and retract them to very little down (less than 1/4) at 22 knots. Be slow to use your tabs and you'll see a settled down boat when you put some gear aboard.

[SeaSpray]

I have never experienced any of these kind of problems. I usually run with tab fully down.

The only time they caused a problem was when I was running down wind/waves and I started getting bow steering as I punched into the back of the next wave.

I would be interested to hear your results when you try the suggestions.

Steve

[Sneaks]

[BRAZO]

I have this problem if I try to trim the boat too much with the trim tabs going fast. After a few times of "what the heck is the problem" (as the wife and kids hold on for dear life) - I figured it out and now only adjust the trim tabs a little at a time when going fast.

[BaseCampAnne]

I was on my first trip with my boat (trying to follow others who were going full speed.) I tried to see if I could adjust the tabs and get on plane, or something, to go faster, and good grief! The boat was swerving like crazy and my passenger was freaking out, as I was, silently. I tried turning them all the way off and then up again and thought surely this isn't happening in this well regarded boat. It was me; I hadn't really asked anyone how to adjust them except to watch out the window and see where the spray is to see if I was up on plane.

I don't know if the tabs were your problem but it was freaky for me!

Anne

[breausaw]

What I’ve observed…..07 22ft cruiser/90 hp Honda/Permatrim/trim tabs

The 22 ft CD is a narrow hull boat for its length, any weight shift buy a passenger will have dramatic effect at higher speeds. I tell everyone onboard to site tight when we’re at high speed cruise.
Try this: put your motor to full down trim and your trim tabs to about 80%, when you hit about 18mph bring your motor up to level…. At this point you should feel a slight increase in speed as the motor comes up. As your speed increases the trim tabs have more effect side to side, what’s right at 18 mph will most likely change as your speed increases. The few times that I actually cruise about 25mph I find the less trim applied down the faster the boat will go, and lateral adjustment only take a tap.

Also, it your light this boat is even more touchy.

In a heavy fallowing sea over extended trim tabs usually make steering difficult, so I only extend them enough for lateral trim while using the motor (with Permatrim) for horizontal.

She’s a touchy little vessel indeed and takes some getting use to..You’ll figure out what works and what to avoid.

[Dan McNally]

Kathleen,
It is unsettling when this happens to say the least. I have experienced the same sensation on my 22 with the same setup as you describe. I found that it was just a matter of over correction on the trim tabs and that people moving about when you are running was the biggest influence you must over come. A little more time on the boat and you will over come this problem.
Dan.

[Ron Cowan]

It sounds as though many of us have had this problem when first getting a C-Dory. In my case, I do not have trim tabs but only a foil on the engine. My '85 Classic is very sensitive to bow down trim with the engine. My first time out presented the worst feeling I have ever had in a boat. Squirley ia an understatment and I thought I had made a mistake in buying it. Figured out it must be me, so trial and error corrected the problem. I now start as bow high as possible and then trim the engine down to eliminate the chop "slap" at whatever speed I am running. The boat is a pleasure then and easy to handle.
Ron

[thataway]

Three is a place to trim the bow down, but that is into chop. Normally let the bow ride a bit high. We didn't have tabs on our 22, but on the 25. Also how fast were you going? I consider the top comfortable speed of the C Dory is 30 mph. These are not speed boats.

Was someone trying to see if they could "rock the boat"? or did it just happen with normal movement? We usually sit in one place when at speed, and don't move around. That may be why we have never experienced what you have described.

[Socrateur]

Trim tabs can cause recalcitrant behavior at slow speeds, too . For example, if you have the tabs way down while idling up to a dock and you want to make a sharp turn to position yourself correctly, it won't happen . They resist directional change and try to keep you going straight . Likewise, if you want to maneuver while backing up, forget it . The tabs have a mind of their own . When you come off plane, raise those paddles up .