Port list in rough water

I have a 2002 353 Fastech and have had it since end of summer 07. It runs great in relatively smooth water but when it gets choppy it always seems to list portside. I noticed this the first year but attributed it to needing to learn how to handle the boat. That wasn't the problem cause it still does it now. I can compensate with the trim tabs but I can't figure out why its doing this. The drive and tab guages are accurate and the rpms are the same at the throttle. I don't have any other handling issues with it. Does anyone have an idea what is going on. The boat has only 170 hours, twin 500hp's and was surveyed and dealer inspected before I bought it so I don't think it had something was amiss when I bought it.

HMK, Lake St. Clair, MI

water conditions will cause that sometimes and its not uncommon. My boat does the same thing once in a while. Wind direction can also add to it. When it gets like that I'll just tab it out a bit.

In the exact same water run the boat directly into the wind, directly with, different angles, etc. See if it is always the same or if the high freeboard in certain directions is the issue.

Surprising what wind and current will do.

I have tried tacking directly 90 degrees into a wave and it doesn't list. However, when its all chop it lists coming, going, etc, and it doesn't seem to have that much effect which way I am heading. I really noticed on a run to Put in Bay on Lake Erie it happened both ways on the same day. In Lake St. Clair it gets really choppy sometimes with heavy boat traffic and wind etc and again it don't make a difference which way I am going. If I bring the drives up and compensate with tabs its better but I have to keep adjusting the tabs with every direction change. I would prefer to keep the drives down more in rough water and so this is a pain at times. Otherwise the boat handles well so I am perplexed as to what is going on. Thanks for the input.

counter rotating I'm assuming... any signifanct weight difference on either side? any steering input needed to keep it going straight or does it just lean? have you checked everything? drive toe, skegs straight, last few feet of hull identicle? swap the props and run it same thing or try a different set??? one of the props get a bad repair job at some point? hydralics tight, not water in any of the fluids leaks or air in the systems?

The drives are counter rotating, no steering input needed, it just leans. Keeping the boat straight isn't a problem but the steering wheel isn't centered when going straight its at about 2-3 o'clock. The drive toe looks slightly in-toed, I didn't examined it closely but it does have a sligt intoe. Nothing obvious. The starboard prop was repaired when I first got the boat during the winter layup and it appears ok, again nothing obvious. Otherwise all the hydraulics are good no leakage or water invasion. Also weight distriubtion not a problem and skegs look good. The hull looks good nothing obvious but how could you tell other than an obvious deformation? I am thinking if the hull is deformed somehow this is going to be a big ugly problem and I'm not sure how the hull could have become "uneven".

Take a long straight edge and look for a hook in the bottom of the boat on the running surfaces. Easy to measure alignment on the drives too. Measure center of propshafts and center of leading edge.

Got my interest now. When we get back from Key West, make sure this gets bumped to the top if it's not there. Need to get the pros on this one......:sifone:

Quote:

---

Originally Posted by phragle

drive toe, skegs straight

---

+1

Toe was my issue- port side would do a wheelie!

Can we safely assume you don't have any fat chicks riding on the port side ...?

Quote:

---

Originally Posted by RedDog382

Can we safely assume you don't have any fat chicks riding on the port side ...?

---

My exact thought! Skinny drive with a fat chick riding shot gun:rofl:

LOL I like the passenger weight distriubtion question, but no thats not it. I do thank you guys for the ideas and will get out to the boat within a few weeks to recheck these things. I am curious too, about checking the hull. Right now its in winter storage on my trailer so getting underneath with a straight edge should be easy.

HMK...back up and think about the physics of what is happening.

when running in smooth water, you have fairly constat contact between the water and the hull
So that means roughly 1/3-1/2 of the hull is in the water (back half) that causes enough resistance that a slight problem with the drives could be overcome, also if you had a major rocker/hook problem it would probably manifest itself. It also tells you that the running surface on that part of the boat is not causing the problem.

The problem happens in rough water..
OK, the boat is bouncing around more so (depending on trim) the nose might be bighting more as it hits a wave ( a problem with a strake or chine could push the boat to one side ..but Im thinking this would also make the boat want to nose steer) or if you have it trimmed out you could be standing it on the drives more, so a prop problem, drive alignment problem weak hydraulic problem would come more into play.

have you tried running on flat water and and running the tabs/drives to really bury the nose to see if it leans? or have you tried trimming everything so your running really light to check?

its on a trailer but you can still get under there with a 3 or 4 foot straight edge to chike the hull and strakes and rocker/hook.

Dont think 'why is it doing this" think 'what WOULD make it do this' then strt eliminating things..

first thing I would do is run it trimmed to each extreme and see what it does, thn try a different set of props and go from there. but since it's in hybernation, its hull check time

It is hard to gauge how bad it is from here... But some boats need more port tab to keep level.. Part can be attributed to motor torque. Both motors rotate to the left. It becomes more noticeable when its flying.

Like others have said an ever so slight variation in the bottom could be the cause. Does the boat float level at rest? I guess a long shot could be the props are not matched..Seems unlikely that would be it though. Could you borrow a set to rule that out?

A friend of mine tuned his bottom on his race boat. It needed more port tab to run level. He added about a 1/16" rocker on one side and it leveled out.

I have run it with drives and tabs up at top end on smooth water without problem. I haven't run with both drives and tabs down lately on smooth water. I did it once when I first got the boat at the end of 07 season and no list was noted then. Water was pretty smooth that time only problem was steering was difficult as you would expect, I was just trying stuff out to learn about the boat. The listing diminishes in rough water when I bring up drives and compensate with bringinf the tabs down a bit with the port tab down a bit more to level out. So next season I am going to try these trim combos out again. I also will see about borrowing some props but I don't think thats it.

Drives are out of alignment or a bushing is loose/worn. You didn't mention whether you have full hydraulic w/tie bar or not but I'm thinking the 500HP boats got the full treatment. There may be just a tad of slack/slop at the gimble, or perhaps a mounting point for the steering. Disconnect the steering and tie bar and wiggle the drives to check for bushing wear.

My bushings were all good but the inner tie bar (no hyd or ext bar) developed about 1/4" of play...just enough to cause a port list. If you don't have external steering and tie bar, check the internal bar.

I have the external tie bar with hyraulics. I am now thinking its the toe position. I am assuming they are suppossed to be parallel and I remember thinking while sitting on the lift one looked off. Now thats in in hibernation I am going to give that a closer look. I don't believe there is play in the drives but will give that a second look also. I appreciate everyones input.
Thanks, Harold

I skimmed over this thread and might have missed it but check Drive and Tab Indicators to make sure they(tabs&dirves) are where indicated .....m

Take all of the change out of your left pocket and put it in your right pocket. That should take care of it!!

Just kidding, does runing the starboard tab down a little take care of it?

I have to run my port tab down to a neutral position on flat water under 60 mph to get it to run level. Over 60 and in the rough it runs and flys level.:huh::huh:

Always get props fixed in sets. My guess is your fixed prop is just tweaked a bit different than the other. A little less cup on the starboard side would have this effect.