Trimming on 280DA

[jason78]

I have recently started experimenting with trimming the outdrives on my 280. So far I have noticed that it does not seem to like being trimmed up even a little anywhere under 3700RPM or so. I am curious what others are doing with trim on the twin drive 280DA config and if I can even expect to see increased speed/fuel economy by trimming. So far I have not used the tabs in conjunction with the trim.

Thanks
Jason

 

[Half Off]

I have the twin 4.3's not the 5.0's like you have but I only trim my outdrives very slightly. The trim gages are too quirky when I trim one drive at a time so what I do is bump the trailer switch 1 to 2 times for about 1/2 second each. Just watch your rpm's and make sure you don't over do it.

 

[Presentation]

This is not our first boat so I understand the feel of a properly trimmed boat.

We also have a 280 Sundancer with twin 5.0's and Bravo III drives.

With this boat and engine / drive combination, all the way down is the correct trim setting for all running conditions except at the upper end of the throttles.

Like you, I only trim at speeds starting somewhere around 35 MPH and then only slightly.

Regarding the trim tabs, I use them to hold plan at slower speeds and to balance the boat.

The boat is very well balanced compared to the 240 Sundancer that I owned before this boat. I don’t need to adjust the trim tabs for balance often but I will on occasion, especially when we have larger guests onboard and they all sit on the port lounge.

Sea conditions may also require some trim tabs for balance.

The reason I will use the tabs to hold the boat at slower speeds would be pulling kids in the tube or rough seas.

With the tabs all the way down I can hold plane as slow as 17 MPG if I don’t want to mess with the throttles much and all the way down just over 14 MPH on the GPS if I am willing to be a busy captain and constantly readjust the throttles.

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[Woody]

When I'm in the 28-32mph range I do run a little trim, about 1. I think I run light compared to all the junk Pres carries on his boat. I also don't have a generator. The faster you go the more trim you can give. At WOT I'm trimmed up alot although I don't remember how much. I don't do that to often. I vary rarely use the trim tabs.

 

[Presentation]

When I'm in the 28-32mph range I do run a little trim, about 1. I think I run light compared to all the junk Pres carries on his boat.

Woody is correct, we run heavy.

It’s due to how we boat.

Three kids, a variety of activities that all require different stuff and our use style that included spending 39 nights onboard last summer, mostly away from the marina all add up to enough ‘stuff’ onboard to make a Chinese Junk owner blush.

From tubing to knee boarding to water skiing to a inflatable raft & oars to fishing to rainy day board games, a portable s’more maker, a grill, enough lawn chairs for us all to gather around the campfire, a variety of electronics that allow me to work onboard, the list goes on and on.

Now add provisions like food, beverages and enough emergency and repair gear and yes, we run heavy.

However when another boater needs a hose clamp, a Allen wrench, jumper cables, some drive fluid, a cable tie, a stainless steel nut and bolt to fix a bimini top support pole or they come onboard to enjoy a mini buffet of Hors d'œuvre no one complains.

 

[JimT]

I was surprised at how quickly my 280 starts to porpoise and cavitate when trimming the engines up. There is some small gain when trimmed up to 1 or 2 at higher RPMs but it quickly goes away if I trim above that. I only us the tabs to balance the boat in a cross wind or if I'm overloaded on one side.

 

[Turtlesboat]

Speed and weight is the key, at about 3500-3600 I can trim them up a 1/4 and get a few kts if the conditions are good. With full fuel and full water, I have to get up to about 3700 rpms to be able to trim. Normally when I start a long trip, I'm not able to trim, cruising at about 3400 rpms. When I get down to about 1/2 tank of gas, I can start to trim the drives up a little. By the time I'm down to about 1/4 tank, my drives are trimmed up to about 1/2 and i'm doing about 31mph at 3400 rpms. this is only if there's no chop. With the dinghy on the back, i'm not able to trim much if any.

In the Sound we can have some serious chop, i'll use the tabs to push the bow into the chop, much smoother ride.

 

[jason78]

Thanks for all the help everyone! It is good to know that my experience so far in trimming is consistient with what others are getting. I tried to go just past 2 and got alot of cavitation so backed off. Just as I expected, a big difference from the 225 that could take alot of trim once on plane.

Presentation: Thanks for all the advice as well. I would love to know where you are keeping all that stuff! We have 2 kids and we have not yet been through a summer on the 280 so I expect to be packed down even more when Spring comes around. When I cleaned out the 225 I could not believe how much "stuff" we had in there from last year.

On an unrelated note, I also had to take the table storage mount out of the bilge to allow access to the A/C thru-hull and strainer. I have Closed Cooling so I have an additional water pickup for each engine which adds up to an additional 2 thru hulls and strainers. I have 4 to keep clean in all. That table storage made it impossible to get to that strainer and anything on the front of the Port engine. My Groco spanner wrench just arrived yesterday so as soon as my back is feeling better I can get down and clean those strainers.

Jason

 

[beerman]

We boat on the same chain of lakes as Presentation and run about the same as Doug. Our lakes are rarely smooth so the oportunity to run at a speed which we can trim the drives is not too often. I also am unable to trim until over the 35-37mph range. Most of the time running 28-32mph with use of the trim tabs instead.

 

[Presentation]

... I also had to take the table storage mount out of the bilge to allow access to the A/C thru-hull and strainer.......

Hey Jason,

Our engine compartment table storage rack is still in place. We added a rack to it to store water skis.

To open and close the sea cocks I remove the skis then use my feet.

Yes, I know my engine compartment is dirty. These photos were taken at the end of the season.

The ski rack is attached to the factory standard cockpit table holder. Yes, the table still fits.

I plan to paint the rack gray like the table storage holder. Its item # 2317 on my to-do list.

 

[Presentation]

.....I would love to know where you are keeping all that stuff! ......

You do know about the 280 Sundancer secret storage compartment, right?

Just to give you an idea, under the cabin’s step trash can we store:

Many empty grocery store bags to use as the trash can liner.

A Orion flair kit – the big round one with aerials, and held, smoke and more.

A generator repair “A” kit that I’ve removed everything from the boxes then added additional items.

A tool kit with many items including open ended wrenches, socket set, metric and regular, screwdrivers, pliers, crimpers, wire strippers, large and small Allen wrench kit and more.

Miscellaneous repair parts kit witih like screws, nuts, bolts, cable ties, fusion tape, electrical tape, wood corks, hose clamps, IAC, engine belt, duck valves, wire terminals, some wire, many spare light bulbs, fuses, much more.

EPIRB – yea, it should be in a ditch bag, but it’s not.

Spare oil for the engine and drives.

Dirt devil vacuum cleaner and a couple of bags for the vacuum.

12V hand held 1,000,000 candlepower spotlight.

An assortment of batteries.

A battery powered Red/Green marine flashlight with built in clamp. Also a white ‘all-round’ one.

 

[jason78]

You do know about the 280 Sundancer secret storage compartment, right?

Yes, thanks to some earlier posts you had made I found the secret storage compartment! Wow you are certainly making the most of your space! I imangine I will have mine packed to the gills too by summer! What size sheets do you use for the Aft cabin?

Thanks
Jason

 

[KHARRIMAN]

I've experienced the same as almost everyone here....
outdrives full down 95% of the time while running. I also start to rpm "rev" around "2" on the smartcraft trim.
Sheets: 1 unfolded old school cloth sleeping bag for base and cal king sheets tucked against the aftmost wall but not the front:grin:

 

[Presentation]

What size sheets do you use for the Aft cabin?

Hey Jason,

Is "Bed" a size? I know my wife used bed sheets.