Planing issues with 2005 thru 2007 350MAG powered 260DA's ?

D

Dave S

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TECHNICAL Contributor
Oct 3, 2006
6,014
Upstate South Carolina
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It's at times like this when I am sorry I do not have the 496 engine in my boat. :smt089

I am getting a bit frustrated with my boat when I have more than 5 adults on board. It just takes way too long to get this thing to plane under these circumstances. Doubly frustrating is the fact that my experience with using tabs has told me I shouldn't use them until I am on plane because it is so difficult to control the "lean over" as the boat comes on plane (reported in a number of other posts on the board as well). As a result I have a 20-25 second time to plane speed with the bow way up in the air until she finally levels out :smt021

What have others experienced when they have a lot of people on board?
 
Dave my boat is a couple of years older and I have the 6.2l engine but once I had 6 full size adults and 3 full ice chest plus misc stuff. After trying to get on plane I stopped and move the ice chests down below and I had to deal with the tilting by using the trim tabs. the tilting doesn't bother me as much as it bothers the guests. Like you I just had to learn to live with it or buy a faster boat. :thumbsup:
 
Just for what its worth, the 6.2L small block V8 begins life as a 5.7L GM small block V8, the exact same GM 5.7L small block V8 that Mercury modifies into the 350 Magnum.

The 6.2L increases the stroke, the distance the piston goes up and down. They also utilize more aggressive cam shaft geometry and accompanying ignition software. Because of these and a few other component changes the maximum RPM is higher in the 6.2L. This gets you an additional 20 ponies however they are all at the top end of the RPM range.

As far as hole shoot, the two engines are identical.

The 260DA had a redesign in 2005. This added more then a thousand pounds to the boat. Much of this is in three areas, the arch weight was not included in the old specs as it was an option and is included in the 2005 and newer, the arch ‘grew’ and was beefed-up, the swim platform was raised and enclosed, and the gunwale and deck was strengthened to get the higher 50+ mile NMMA ocean rating. Also the cockpit seating adds some weight.

So all else being equal the 2005 260DA would take a bit longer to plane then the earlier models. A small price to pay given the improvements.

My suggestion is to fully trim down and slightly tab down. Assuming you are like most and do not have tab indicators, try fully raising the tabs, (lower button) so they are all the way up then press say 5 seconds on each so you are as close to level as possible then adjust once you are up to speed.
 
Another peculiar trait of this boat is that if you leave the drive tucked down all the way, the boat definitely won't plane with a load. :smt101 You actually have to begin tiliting the drive up while it's trying to plane in order to get it to plane. :smt021

I would be interested to hear if any of those folks with the 496 have planing problems under the circumstances I described. I am almost at the point of seriously considering swapping my 350 for a 496 at this point (psssst..............don't tell my wife about this. :smt018 )
 
Presentation said:
The 260DA had a redesign in 2005. This added more then a thousand pounds to the boat. Much of this is in three areas, the arch weight was not included in the old specs as it was an option and is included in the 2005 and newer, the arch ‘grew’ and was beefed-up, the swim platform was raised and enclosed, and the gunwale and deck was strengthened to get the higher 50+ mile NMMA ocean rating. Also the cockpit seating adds some weight.

So all else being equal the 2005 260DA would take a bit longer to plane then the earlier models. A small price to pay given the improvements.
Click to expand...

Hmmm. Can you tell me more about the NMMA ocean rating?

_________________________

On the surface. . .this is a very damaging threat. Addition of 1000 lbs to a boats *base weight* is not trivial for a boat of this size. If I read this thread correctly, it is the difference between *able* to plane and *not able* to plane.

A small price to pay? Must be marketing in action. I mean. . .this looks like a clear case of "form over function". Without the Arch and the Extended Swim platform. . .you don't get a buyer to commit. And without committment. . .there won't be a Seatrial. And who does seatrial with a boat full of people AND full of fuel, which reveals the planing problem.

I was a huge fan of the Arch concept. It looks really cool. I wanted one. . .but when I bought my 280SS, Arches were only on the "too new and too pricey" boats (now called the 290SS). Now I read a thread like this one. And I know the 290SS weighs in 2000lbs heavier than my 280SS. Hmmmm. Maybe I am glad I don't have an arch.
 
comsnark said:
Hmmm. Can you tell me more about the NMMA ocean rating?
Click to expand...

NMMA has classifications for this.

A - ‘Ocean’
B - ‘Offshore’
C - ‘Inshore’
D - ‘Sheltered waters’

A. OCEAN: Designed for extended voyages where conditions may exceed wind force 8
(Beaufort scale) and significant wave heights of 4 m and above but excluding abnormal
conditions, and vessels largely self-sufficient.
(note: generally accepted as greater then 50 miles offshore)

B: OFFSHORE: Designed for offshore voyages where conditions up to, and including, wind
force 8 and significant wave heights up to, and including, 4 m may be experienced.
(note: generally accepted as 3 - 50 miles offshore)

C: INSHORE: Designed for voyages in coastal waters, large bays, estuaries, lakes and rivers
where conditions up to, and including, wind force 6 and significant wave heights up to,
and including, 2 m may be experienced.
(note: generally accepted as less then 3 miles offshore)

D: SHELTERED WATERS: Designed for voyages on sheltered coastal waters, small bays,
small lakes, rivers and canals when conditions up to, and including, wind force 4 and
significant wave heights up to, and including, 0,3 m may be experienced, with
occasional waves of 0,5 m maximum height, for example from passing vessels.
(note: sheltered coastal and inland waters)

Craft in each Category must be designed and constructed to withstand these parameters in
respect of stability, buoyancy, and other relevant essential requirements listed in Annex I, and
to have good handling characteristics.

NOTE: The Design category parameters are intended to define the physical conditions that
might arise in any category for design evaluation, and are not intended for limiting the use of
the recreational craft in any geographical areas of operation, after it has been put into service.
The physical conditions shall be determined from the maximum wind strength and wave
profiles, where wave profiles are consistent with waves generated by wind blowing at the
maximum stated strength for a prolonged period, subject to limits of the implied fetch and the
maximum stated wave heights, and excluding abnormal factors such as sudden change in
depth or tidal races.

For category D, allowance should be made for waves of passing vessels up to a maximum wave height of 0,5 m.

For category A, unlimited conditions apply as they reflect that a vessel engaged on a long
voyage might incur any conditions and should be designed accordingly, excluding abnormal
weather conditions e.g. hurricane

http://www.nmma.org/certification/local/downloads/documents/2006_RSG_Guidelines.pdf
_________________
 
There's a reason they call it the "base" engine. Will the boat work with this setup? Yes. Is it the ideal setup under all load conditions? Well, like the 5.0MPI base engine on the 240DA I think we already know the answer to that question.
It's all about trade offs.
 
If I had a lot of people in my 2000 - 260 - I would have some issues planing - I would trim as I was coming up on plane and get more aggressive with the throttle.
 
I can almost live with the slow to plane "feature" :wow: except when I am trying to pull a water toy such as a tube and my bow is pointed towards the sky while I try to get the boat to plane. I can't tell you how frustrating that is and a bit unsafe as well. And it's certainly no fun for the tuber. :smt089

As JG said, it's all about trade-offs, but in my opinion if you make the cockpit big enough to seat 7 or 8 people then you better design the hull and the powerplant to deal with those conditions. As far as I am concerned the 350 powerplant doesn't work well at all to bring the boat up on plane when you have a full compliment of people.

I am still curious how the boat performs with the 496 and a full compliment of people. Maybe Thunderbird will chime in here since I know he has the big motor.
 
Hey Dave,

On items stored onboard, can you relocate heavy items further forward?

Part to would be your anchor rode locker. Save two dozen empty gallon milk jugs. At the dock, fill them with water. Put them in the anchor rode locker on the bow. Now go for a ride and see if this is a noticeable improvement. If yes, consider getting an all chain rode. If no, you are not out any money and only a little time.

Water is about 8 lbs / gallon. So 24 jugs full of water is about 200#. It sounds like a lot, but a all chain rode would weigh this much.
 
Cool. Thanks for the NMMA info.
I can't seem to figure out what I have from the downloaded manual . . .gotta look at that decal tonight!!
 
Doug..........not a bad thought but without a windlass I am getting tired just thinking about hauling in 200 pounds of chain. :smt100 :wink: Eventually I will work something out on this issue and maybe adding a bit of weight to the bow will at least help the problem somewhat.......it's just that it will have to be something other than a chain rode.

I guess at this point I am just venting a bit because we really never noticed the planing problem to any degree until recently when we started increasing the number of people we had in the cockpit. In fact during the winter months we had nine on board one time but a couple of those folks were seated in the cabin and there were no planing issues back then.
 
Dave S said:
Eventually I will work something out
Click to expand...

Shore term budget friendly solution: Take out all the rope anchor rode, take a couple of cement blocks that you wrap in some padding to protect your boat, put them in your locker, replace your rode on top of the blocks.
 
Better yet, lead bricks. They take up very little room. A 25# brick measures only 2" x 4" x 8". I used a few to solve my listing problem.
 
Eric,

Neither did I till I checked the internet. I found a company in Mass that made lead products for Nascar. Apparently they use these things in race cars as ballast. They're not cheap, about $40 a piece, but they take up very little room and they work.

Joe
 
jg300da said:
Eric,

Neither did I till I checked the internet. I found a company in Mass that made lead products for Nascar. Apparently they use these things in race cars as ballast. They're not cheap, about $40 a piece, but they take up very little room and they work.

Joe
Click to expand...

Yeah, but I heard they are as heavy to carry as lead bricks.


Sorry, I could not resist.
:smt043
 
I have some old elevator weights at the house that the last owner left behind. (giving away my age for knowing what they are) They weigh about 15# a piece have a hole through the center, stackable and are about the size of a softball. If you could find some...
 
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