Getting 280DA on plane & trim tab use

R

roger275

Member
Jun 24, 2009
94
TX Gulf Coast
Boat Info
380 Sundancer 2003 (Sold)
280 Sundancer
Engines
4.3 Liter MPI Mercruisers with Alpha 1
I just picked up this boat and had trouble getting to plane so hope to get some pointers how to set trim tabs and drives.

With tt's retracted (full bow up) and drives down (full bow down) it takes a long time to plane and plows with bow way up for a while. I must fully extend the trim tabs with full throttle to get her up on top. The tt's don't have indicators so it was a bit squirrely getting them reset after on plane. This is my 2nd boat with tt's and I thought I should be able to plane with them retracted and drives down, then use tt's as needed to level out. Thanks!
 
There's something wrong with the boat......I (and many others here) had the same combo (I assume you have alpha drives) Weight should not be a factor as I had 9 people full fuel etc etc and never had an issue - is the bottom clean - are the wrong props on it - are you reaching specified rpm? could the prop hub or drive coupler(s) be slipping? We need more info
 
yes, more info. How long is a long time to plane? You should be able to hop up on plane in about 8 seconds with no tabs and the drives down.
 
Thanks for the replies. With tabs retracted but drives down, I actually gave up getting on top since it was taking so long - maybe 7 seconds of plowing. I set tabs full bow down and it did ok getting on top but I scared everybody getting them retracted again. After on top it had no problem running 35mph and I didn't open it up much. My experience with tabs is to keep them retracted unless needed to correct listing. Is this correct for this boat?

Its a freshwater boat (until now) and had green stuff on the antifouling painted hull. They did a so so job with pressure washer getting the green stuff off when I picked it up but SS props still have about a 1/32" thick lime looking coating. Maybe this is the problem. I will buff this away and try again (especially now I know its suppossed to do better). Engines revved great and factory props are not damaged.

Thanks again.
 
roger275 said:
I actually gave up getting on top since it was taking so long - maybe 7 seconds of plowing.
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7 seconds is a long time? I have 5.0's, I can get out of the hole and on plane in around that time. Seems reasonable to me :huh:
 
gnealon said:
7 seconds is a long time? I have 5.0's, I can get out of the hole and on plane in around that time. Seems reasonable to me :huh:
Click to expand...

But I was still plowing and gave up after about 7 seconds.
 
It almost sounds as though you had a stick or some kind of debrit stuck in front of the drives. I've had this happen when there is a stick or log that gets stuck crossways in front of my drives. A few seconds in reverse clears the debrit and away I go.
 
fouled bottom and running gear will kill performance big time. clean everything well and try it. You have to push the throttles to about 3400 rpm's and in about 7 seconds you should be up and then you throttle back to stay in that 3400 rpm range.
 
I put the shiny props back on and tried it today. Even with 6 people aboard it got on plane from 3500 RPM in about 7 seconds. We idled along for half hour and suddenly an engine died and would not idle again. Sounds from other posts like an IAC (2 beeps from SC and runs fine above 1200 rpm). Oh well, always something I guess...
 
Replace both IAC's and put the still working one in you spares bag.
 
TurtleTone said:
Replace both IAC's and put the still working one in you spares bag.
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10-4. Is the IAC highly visible where I'll recognize it when I get the new ones? Who do you use to order engine parts online?
 
agree with the advice, I only use my trim tabs to level. No need to get on plane. I plane in less than 10 secs and stay under 4000 RPM.
 
Cleaning the props solved my getting on plane problem but now I'd like to ask other 280DA owners where they run their I/O motor trim. I trim all the way down to get on top but then expected they'd need to be trimmed up a bit to raise the bow and plane better. At least all my other boats have been this way. But even in flat water, if I get the 280DA's trim indicator arrows much above the peg, RPM's start to indicate I'm getting the props out of the water. Are there adjustable stops on the I/O drive down? They way it is makes it seem they are too high and planing would be easier if they could be set lower from a dead start....
 
In order to trim the drives up on our boats, you have to hit a certain speed. I find that anything below say 25mph and you'll notice that the props will start to cavitate and the rpms will jump up and the boat will squat and fall off plane. Hit about 30mph and you can trim them up about a 1/4 and get an extra few mph. The faster you go, the more you can trim them up before the boat starts to porpoise.

It also depends on how much fuel and water you have on board.
 
Last edited:
TurtleTone said:
In order to trim the drives up on our boats, you have to hit a certain speed. I find that anything below say 25mph and you'll notice that the props will start to cavitate and the rpms will jump up and the boat will squat and fall off plane. Hit about 30mph and you can trim them up about a 1/4 and get an extra few mph. The faster you go, the more you can trim them up before the boat starts to porpoise.

It also depends on how much fuel and water you have on board.
Click to expand...

+1 Below 22 knots (25mph) the drive trim position doesn't make any improvement.

Henry
 
The only time I ever have any problems planing off is with 9 to 10 adults on board, everybody in the cockpit, full fuel, full water, lots of food and drink. Drive tucked in, and full tab. The BIII is biting the water and it will not get above 3000 RPM. So, send just one adult to the vberth and she planes off nicely. As soon as she gets on plane, back off throttle, leave in a tad of tabs, and start trimming out. Once people start moving around and a few are in the cabin, you can go on/off plane anytime.
 
I had 7 adults, 1 baby, a couple of full coolers, full tank of gas and water tank and could'nt get up on plane. I plowed for what seemed to be 30 seconds. The only way I could get on plane was to send 3 of the guys in the cabin and then she popped right up. I'm use to OB's that get on plane very quick. Is this normal? I would think the boat could plane with 7 people? Waht type of props are normal on this boat? With only 2-3 people on the baot and half tanks (water and gas) if I raise my TT while on plane it seems to cavitate immediatly. Again I'm used to smaller boats with OB's so if this is normal I'll learn to deal with it.
 
Do you know what your WOT RPM's and top speed is? Is the bottom dirty? Growth on the drives?
 
The boat is lift kept and has no bottom paint. Bottom is 100% clean as are the drives and props. The edges of the props seem a little worn (ran through some sand). Top end is around 40 MPH around 4000 + RPMs (burning a lot of fuel).
 
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