2006 240 INSTABILITY

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capnjohn

New Member
Jul 31, 2007
28
lake michigan
Boat Info
380 sundancer- 2008
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horizons
I own a new 2006 240 Sundancer with the Bravo 3 outdrive. I have owned many boats, but this one is very instable. At speed, the boat will list to either port or starboard, and the trim tabs have to be constantly tweaked to keep the boat level- Without constant attention, the boat will tip to one side and the severity of the list makes it feel as though the boat will tip over.

The only way to stop the tipping is to back the boat down to where is it barely on plane.

This condition is much worse as the gas tank is emptied through normal use- below half a tank, it is much worse.

I purchased a Stingray Hydrofoil piece for the lower unit, but it did not help to correct the problem.

This past weekend on Lake Michigan, in following 3-5' seas, it was a nightmare with every larger swell seeming to tip the boat.

I am interested in anyone's suggestions as to how they have resolved the problem....

Thanks



 
There was a thread about this very problem on this same model about a month ago. I think it was on this site. (could have been on Boattest).
 
capnjohn................First of all welcome to CSR. I think we can help you.

It seems from many of the postings here on CSR that the newer 240DAs as well as the newer 260DAs are very difficult to control. I believe both hulls suffer from Bow Steer whereby the boats want to veer to port or starboard. And these problems are aggravated by changes in speed and the use of trim tabs or the tilt angle of your outdrive. It took me many months how to learn how to control my boat.

First the basics..........When comming on plane do not use your tabs under any circumstances...........have them totally retracted regardless of the load in your boat. If the tabs are down at all the boat will want to veer left or right and that isn't what you want. The next thing you want to pay attention to as you come on plane is your outdrive trim. Start with the outdrive fully down but as the boat comes on plane, begin to tilt the outdrive up. Mine tends to start a list or turn to port as it's comming on plane but the more I tilt the outdrive the more it will cancel that tendency and the more the boat will track straight and level. Once on plane and with the outdrive trimmed properly, then use the tabs as needed to balance the boat side to side.

If you want to cruise at less then planing speeds, bring the boat up to the speed you want, leave your outdrive tucked all the way down and slowly tap the tabs buttons to plant the nose alternating bewtween the left and right side. Be aware though if you change speeds first retract the tabs or the boat will again start to veer or lean to one side or the other.

In heavy seas where you have to vary your speeds, if you understand the "quirks" of these boats as it relates to the tabs and outdrive trim then hopefully you can control it better. Personally I have never had to deal with situations like you experienced on Lake Micigan. Hopefully some of our members who boat on the Great Lakes or on the Oceans can add some additional help here.
 
240 Da Instability

Thanks for the advice and the reply-

I have owned many Sea Rays ( In Order of Purchase ) 215, 270 DA,370 DA, 225 Weekender, and a 240 DA.

The only other Ray that I had that was squirrelly like this one was the '98 270 DA. It wanted to fall over all the time as well.

I understand what you mean about how to bring it up on plane and all of that, still, I don't know it that is the answer to this problem. The boat acts this way in calm water as well as a heavy chop.

I am wondering about the concepts of adding ballast to the hull in order to weight it down As I mentioned in my original posting, the problem gets worse as the fuel tank empties.

capnjohn
 
Have you talked to your dealer or directly to Sea Ray about the problem?

I also wonder if your bow is planted too low at cruising speeds especially as your tank empties out. I know my 260 will take a lot of trim which brings the nose up nicely. Conversly if I want a" thrill" all I have to do is lower the drive and plant the nose and the boat will tip and veer something fierce.....enough to give you a good scare. Conversly, when I had my 240SD I used to regularly plant the nose down at speed to cut thru waves rather than bounce over them and it never had one bit of bow steer.
 
Oddly, I went the other way.

I had a 240 Sundancer and found I frequently adjusted the trim tabs. I just figured that is the way it was. Also, with the 240, as a person changed locations within the boat or if I changed my heading I needed to readjust the tabs.

Now that I have moved to a 280 Sundancer, a heavier, longer and wider boat I rarely touch the tabs after the initial setting. I chalk this up to one of the benefits of doubling my fuel usage.
 
capnjohn,

I feel this on my 240DA only when swells and wind are approaching from either side. Weight distribution and, as above was mentioned, trim tabs along with drive trimming should do the job. Also, in the rougher conditions I would bring the bow down to have smoother ride. This will also make the boat tilt from side to side, so I try to find the sweet spot using the drive trim.

Alex.
 
my dock mate just got a new '06 240DA and there is a noticeable size difference between his and my '03. The boat looks and feels smaller and thats not something the 240 needed to be. I dont have the problems you mention here except for following seas and beam seas. Are you sure one of your trim tabs isn't stuck down? The only time i have that very uncomfortable tipping feeling on mine is when i forget that ive got my tabs deployed and jump back up on plane. Just remember that your starboard trim tab button controls your port side tab and vice versa. Oh yeah, and up on the button means down on the bow and vice versa... :smt101

Mike
 
I always thought the steep transom deadrise combined with a short and narrow hull plus a tall cruiser build causes the instability issues with the 260DA. I cannot think of another express cruiser manufacturer putting a 21 degree deadrise into a small express cruiser hull.

The 240 is at 18 or 19 degrees, so not sure why it is so tippy. We had a Four Winns 248 Vista with 24 foot hull length and 18 degree deadrise before we got our 340 and that boat was as stable as our 340 ... rock solid on plane even with people moving about. It also was slicing better through chop than our 340 can ... at least with less slamming even when applying tabs to keep the bow down. The old 340 with 19 degrees deadrise is not a really good rough water boat.

I am a Sea Ray fan, but frankly I believe there are much better express cruisers from other manufacturers that offer more useable space and use this space more efficiently than Sea Ray until you get to the 340 from which going up the Sea Ray design and space utilization is superb.
 
Capnjohn, sounds like you have plenty of experience with boats, so I'll tell you my opinion. My opinion is not very popular here but here goes anyways.
I have a 2006 240DA and have been fighting the same instability issue. I have talked to Sea Ray and Mercruiser engineering and design teams. I don't exactly know how to interpet what information I have recieved from them, they are way above my level of comprehension or speak in a language that, (hold on to yourself) covers a bad design.
That said, Dave S is correct in his advice to you on how to "manage" the listing and instability. I believe the instability comes from Sea Rays effort to design a more sea worthy boat that can get a better hull rating. I believe there is not enough water line length to off set the deep vee configuration. If you measure your hull from the stern, At the drive offset to the bow you'll see there is approxmately 18 ft of wetted surface to "hold up" the weight of the boat. Not enough. They integrated the swim platform and the measured hull length includes this platform. (that doesn't help with bouyancy becaues it does not touch the water) IE, wetted water line length is alot less than length overall. The vee runs all the way to the front and is deepest at the bow. (Gives better head room in the cabin) which is normal except the reverse chine to knock down spray for a drier ride in larger seas is very pronounced and provides to much lift.
The instability is due to the hull lifting itself to high out of the water (This is all relative of course) and flotation resting to near the center line of the hull at speed. The raised helm to provide room for the aft cabin raises the center of gravity and is detrimental further.
As you trim your outdrive out this transfers the pivot point further aft, thus squatting the stern and artifically creating weight. As the hull sits deeper in the stern it starts to rest on the reverse chine and becomes more stable. It also lifts the bow out of the water creating less bow steer. However there is a fine line between this stability and porpoising due to "cruising speed". As you increase speed you notice the porpoising increase thus the need to adjust for more negative trim. So that is why you see the need to chase the trim tabs and drive trim
I don't know what the answer is or if there is a consumer fix. I think if you balast your boat with more weight you'll see an improvement, but at the expense of fuel mileage and time to plane and over all efficiency.
I ran my boat in the ocean in the condiditons you describe and feel your pain. All I can say is, as you learn the quirks of your boat you'll become better at anticipating it's behavorial traits.
I hope this helps, and understand this is all my opinion based upon trial and error and some reasearch. Mike
 
To me the instability of the 240 could be caused by undersized chines and/or strakes too.

Our 248 Vista had very large reverse chines and broad strakes towards to outside of the hull, while none in the center towards the keel that stabilized the hull very well. Also with 6000 lbs. dry weight the 248 Vista was on the heavy side for a 24 foot EC.
 
Looks like we've got a bunch of us all figuring this out at the same time. I've only been out on my '05 260DA one afternoon, and I had the exact same experience. I had it trimmed "right" a couple of times (by accident), and the boat was handling fine. Dave (friend & co-owner) moved, or we changed direction and she would need some adjustment and I just couldn't retrim her back to where she needed to be.

This is clearly a case of us simply not having a feel for what changes what, and which trim to use when. I took flying lessons for a while. This played a part in the problems that I was having. A couple of folks on here pointed out that unlike ailerons, the right trim button works the let trim tab. Well blow me down. I was trying to correct a lean to starboard by hitting the bottom of the right trim button. That should have lowered the right tab a bit, lifting the starboard side level. In reality, I was actually lowering the left tab, which put me in the same situation that you encountered.

Since we have knowledgeable, experienced, drivers right here, and multiple people asking the same questions. I will ask a few related questions that I was going to ask in a new post.

I put my 260DA on a wash rack at the marina. I put the trim tabs all the way up. I then had Dave hit the top of both trim buttons for about 5 seconds. The back edges of the tabs had lowered about 3" or so. In an airplane that would be a very hard turn if not a full blown barrel roll, depending on how fast you were going. This HAS to be way too much tab for "normal" use on a boat, correct? My guess is that 1/2" of travel ought to be enough to correct for just about anything above 5 mph or so. At speed, even less would be required. This amounts to pressing a trim button for about 1/3 of a second. Is my logic correct, or is more tab required?

Both tabs should not be used at the same time, correct? If I correct for a port bow high list by hitting the top of the left trim button, the starboard tab will lower to correct the condition. If something changes and she develops a starboard list, I should first hit the bottom of the left trim tab retract the previously lowered starboard tab before even thinking about using the top of the right trim button to lower the bow on that side. Otherwise, I would end up lowering both tabs further and further as I kept correcting for each condition. The result is that the bow keeps getting planted further and further until I end up putting the boat in a condition that it wasn't designed to be driven in. Not to mention all of the drag associated with the tabs being deployed that far. In effect, the tabs would also be "fighting" each other. I am just along for the ride at that point, not really in control at all.

If I need to change speeds after being trimmed for a while, should I get in the habit of adjusting the throttle first and then hitting the bottoms of both trim tab buttons to retract both tabs before trying to retrim, or should I retract the tabs first and then adjust the throttle?

Why didn't Sea Rav put trim tab position indicators on the panel? This would help tremendously.

Regarding power trim, I was entering the marina for the first time the other day and was having a little difficulty controlling her at slower speeds. I had the outdrive pretty far up because I knew there were shallow spots close by, I was unfamiliar with the waters, I was nervous, and the depth alarm had gone off a couple of times. With the boat in the wash rack yesterday, I could see that there is very little, if any of the "fin" (rudder?) of the outdrive (the flat surface coming off of the bottom of the prop shaft housing tube) projecting below the bottom of the boat. My really stupid question is: is this the reason she was all "squirly" on me trolling into the marina? I need to keep the outdrive further down than that to have proper control, correct?

This all seemed related to captnjohn's original post. Captnjohn, please ask the mod to move this if you feel that it is a hijack of your thread.

Michael
 
IslandHopper00, you're not out there alone, I think you've got a perfect handle on it. I know the Sundancer has been more popular, but as a Weekender owner, I have to agree with your assessment of the Sundancer model as contributing to the problem - especially in these smaller sizes.
To compare some of the above stats, my 1980 26 Weekender has 21 ft of waterline, 23 deg of transom deadrise and 8.0 ft of beam. It is amazingly stabile at all speeds while underway, but can be quite rocky while at anchor. Newer hulls have more detail to combat that. Tabs don't cause me a problem, although I use them little. My transom is incline in a little and I rarely adjust my outdrive. It seems to like it in at all speeds. My bow rise is also much more limited than newer models. It never gets very high.

The original message I was thinking of is this title, posted by Dave S, right here in the Cruisers section. It has almost 5000 views!

Planing issues with 2005 thru 2007 350MAG powered 260DA's ?
 
cap10pat, Thanks. I'm not sure what a fix will be except to live with it. I'm sure Sea Ray knows about the issue (I've talked with them) but boy you'd think "they" wouldn't want their customers living with an issue such as this. I also think it is a function of safety should an inexperienced operator find him self in unpredictable weather. Sea Ray feels the hull will not roll over, just be uncomfortable at worst. As capnjohn pointed out this hull is scary in a following sea, and in the wrong hands could be disasterous. I guess I'm getting way to pasionate and letting my emotions get the best of me, but if I hear of a personal loss due to this problem I for one will be very sad.
Hopefully that explains why my latest posts have been contraversial. I don't accept the answers provided to me by Sea Ray, and I wonder how some people sleep at night.
 
240 Instability

Thank you for your interesting perspectives on the problem that I am experiencing with our 2006 240 DA.

From the replies that I have seen so far, the issue we have is not unique to our boat, and indeed, others are suffering with the same problem.


In attempting to help me resolve the issue, many of you seem to be focusing your thoughts on proper use of the trim tabs as being a part of the answer to the instability issue with the 240 DA.

In reality, the tabs help correct the problem, but not completely, and not in every type of sea condition. In short, tabs and their proper usage can not be considered the answer to the hull design issue.

The question remains, what is the solution to the problem. Can this problem be rectified by the boat owner, or is this a Manufacturer issue.


I am wondering if we as a group of owners should approach Sea Ray and ask them to help.
 
capnjohn, I'm with you on this one, I believe we are thinking along the same lines. Trim tabs manage the problem, doesn't fix it. I think it's a manafacturer problem. At this point I have contacted Sea Ray and do not accept their answer. I hope enough attention is drawn to this issue so that some form of answer is required. I hope further that people understand this condition is not normal and should not be accepted. This condition only worsens as sea state rises. For thoes of us who use our boats in unfavorable conditions (not by choice) it scary at best.
Lets unite and demand some answers, that what I say.
 
I have a couple of questions for the 240DA guys. Do people with the older style hull (pre 2006) experience the same problems being discussed here? Does anyone with an older 240DA know what the deadrise is and what the actual wetted hull length is? I am trying to understand myself if this problem has always existed with the 240DA or if the hull design of the newer model is that much different and the boat reacts differently as a result of it.

I know that on the 260DA they went from a 19 degree deadrise up to a 21 degree deadrise when the model changed in 2005. I would also like to know from any other 260 guys that might be reading this post if they experience problems in heavy open seas. I boat on an inland lake and don't have to deal with the same issues. Right now, as long as I follow the procedures I mentioned earlier my boat runs mine. But I also know what happens if I don't do things properly and like I said it can get a bit scary. Having said all that I also don't have any other cruisers I can compare this to since this is the first one I have owned.
 
The first time I operated my boat I knew something was drastically different about the handling characteristics. After hearing all the new 240/260 owners with the same complaints I now know it is not operator error but design flaw. Simply trying to put too much boat in too small of a footprint. I think Islandhopper has a firm grasp of the problem. The tabs seem to exacerbate the problem by lifting too much of the hull out of the water. Like the others I have learned how to keep the ride stable with the trim and judicious use of tabs.
 
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