Duoprop Boat lists to Starboard, but only on-plane

[Mercury9]

Hi,

I have a 2007 Glastron 279 with a Volvo Penta 5.0 and a V-P DPS "Duopro" outdrive. The boat lists to starboard while on-plane. I've already ruled out the wind and weight distribution of anything that is "movable" without the use of tools (people, gear, equipment, etc. I haven't moved the batteries or any liquid tanks, but I estimate those items to be even or, if anything, heavier on the port side the way I cruise). I've also confirmed that my trim tabs are zero'd-out when I start. The props are factory spec and they counter-rotate. Does anyone have any thoughts? Thanks!

 

[Scott Danforth]

Stand on the port side and it may list to port. When my boat is on plane if someone gets up and moves, the boat changes its list.

what side is the fuel tank on?

batteries?

use your trim tabs to even out the list, thats what they are for.

 

[JoLin]

use your trim tabs to even out the list, thats what they are for.

V-hulled boats also list (lean) into the wind. Like Scott said, use the tabs. I adjust mine constantly when under way, like anytime my heading changes.

 

[Mercury9]

Scott & JoLin,

I'll try to explain more clearly... I know it's not the wind because I run the boat on a north-south river and I've turned the boat around many times to see if wind was a factor. It's not. It lists to starboard in both directions. The boat has been doing this for the two years that I've owned it and I've been correcting with the trim tabs, very effectively when there are 1 - 4 people on the boat. When there are more people, the trim tab slows the boat down quite a bit, so I'd really like to solve the problem. Yes, I do balance my passengers (to the extent that they're honest about their weight). I normally leave the marina with a full tank of water (port side) a full hot water tank (port side); an empty waste tank (stbd side); two batteries (stbd side, but closer to the centerline); and a fuel tank that sits in the middle. So I think if anything there's more weight on the port side. It sits level at the dock. When I am by myself, I can get out of the stbd side captain's chair and stand/steer from the center and it doesn't correct the list. I can and do correct with the trim tabs, but I'm trying to find the cause. Surveyor says the boat is dry.... Thanks!

 

[hemi rt]

I'm wondering if you have a soft hull on the starboard side, that would make it list the way you are describing it. We had a Rennel that did this due to a soft hull, had to diassemble it from the inside, re-fiberglassed the complete hull then rebuilt the stringers and floor. This solved our problem.

 

[Mercury9]

The surveyor said everything was dry. Besides, wouldn't a soft hull cause it to list when not on plane as well?

 

[Scott Danforth]

if the hull has a hook or a soft spot, you wouldnt notice it until its on plane

 

[Mercury9]

I'll check for a hook, but nothing noticeable when I was scraping the paint. Thanks!

 

[JoLin]

I wish my boat was so well balanced and designed that trim tabs were unnecessary. My Carver is my 5th boat, and every one of them usually needed the tabs to maintain an even keel. You say the problem is worse when you have more than 4 aboard. Other factors also come into play when you have a 27' boat with full tanks, 5+ passengers and a single 5.0. There's more hull in the water. The engine and props are working harder. The boat will be more sensitive in several respects.

I think when all is said and done, you'll find it isn't a 'problem'. It's simply the nature of the beast when you're fully loaded. You'll need to apply more trim.

My .02

 

[southkogs]

Is there a trim tab on the outdrive?

 

[Mercury9]

No sir...

 

[Powerstroke in a Prius]

That 23 gallons of water on the port side somewhat compensates for the weight of the driver on the starboard side. I would expect the boat to bog down a bit when you load it up with more than 4 people over the 5.0L. The 5.0L is great (for fuel economy) for an intimate party of two with gear, not so much with ferry duty.

You have a deep vee hull (congratulations) - it's gunna list while on plane. All you can do is trim the lower unit up/down to get it close while optimizing your speed, then fine-tune with the trim tabs.

 

[Alumarine]

What happens if when on plane you bring both trim tabs to the full up position and then start putting the starboard tab down in increments.
Does that not level you out?
Or do you need both tabs down to maintain plane?

 

[Lowlysubaruguy]

Does it have a plate for an adjustable trim tab on the outdrive. It will most likely be close to 3" in diameter. It might have a place for one. Id also look all the fins on the outdrive for bends or heavy knicks that could cause drag a lightly folded edge or something. Both props are spinning right? Dont know but id have to assume the drop prop work also to counteract forces. Ive spent a lot of time on my buddies 92 duoprop. His had no adjuster on the outdrive but it had a spot for one.