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PostPosted: Tue Jul 11, 2017 9:36 am 
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Hi All

I must confess to being a little unsure what I am doing when using both kinds of trim
Firstly , the Bennett trim Tabs
I operate in the Med sea, where its never flat calm (well rarely)
How Should I be using the trim tabs here? when do they go down , and back up again?
At the moment I am adding a little bow down trim equally on both sides to stop the bow rising as I add power ...the boat then eventually gets on the plane....do I then bring the trim Up again?
What about different conditions? rough sea or following swell?
When should they be completely returned to bow up?

The outdrive trim
I am completely perplexed with this one...I leave it permanently DOWN, as every time I trim up even a little it seems just to slow down the boat and make more noise
nothing seems to be of any benefit so far using this LOL

when do I use this trim?

any help MUCH appreciated on this !
sorry if its a pretty basic question

all the best

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Bill P
Marbella, Spain
Vista 248 Year 2000
25th Anniversary edition
Volvo Penta Engine and Outdrive


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PostPosted: Tue Jul 11, 2017 10:31 am 
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268 Vista

Joined: Tue May 16, 2006 9:49 am
Posts: 4989
Location: West Michigan
At the moment I am adding a little bow down trim equally on both sides to stop the bow rising as I add power ...the boat then eventually gets on the plane....do I then bring the trim Up again?
Tabs fully extended and sterndrive fully in when getting on plane. Once on plane, trim sterndrives out and bring tabs up fully.

What about different conditions? rough sea or following swell?Depends on conditions, adjust for most efficient ride
When should they be completely returned to bow up?Return tabs once on plane, adjust left or right for wind and weight in your boat to level the ride.

Sterndrive trim fully in when getting on plane, trim up as needed until RPMs increase and you are riding smooth.

It sound like you are over thinking everything.
You can read these, and probably explain better than I did.

http://www.boatus.com/magazine/2015/apr ... basics.asp

http://www.boatus.com/magazine/2014/jun ... n-trim.asp

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One of 4 Previous (Sold) Boats:
2000 Four Winns 268 Vista
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Last edited by Cap'n Morgan on Tue Jul 11, 2017 10:37 am, edited 1 time in total.

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PostPosted: Tue Jul 11, 2017 10:35 am 
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"It sound like you are over thinking everything."
LOL Im sure I am

thanks for the great advice !

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Bill P
Marbella, Spain
Vista 248 Year 2000
25th Anniversary edition
Volvo Penta Engine and Outdrive


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PostPosted: Tue Jul 11, 2017 1:47 pm 
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Posts: 2032
Location: West Palm Beach, FL
wakevortex wrote:
The outdrive trim
I am completely perplexed with this one...I leave it permanently DOWN, as every time I trim up even a little it seems just to slow down the boat and make more noise
nothing seems to be of any benefit so far using this LOL
when do I use this trim?

Same as Cap'n said, I leave my outdrive trim all the way down for starts and getting on plane. Also for tighter turns when on a plane.

While on plane at 25-35 mph, I trim out (up) just enough that the anti-ventilation plate stops spraying water up behind the boat (the round drops that spray everywhere from the drive when it's trimmed to far down). About 1-2 seconds of trim is enough to make the anti-ventilation plate parallel with the bottom of the boat. That will be an efficient setting for most Four Winns hulls at medium planing speeds.

While at high speed, I trim out even further looking for a sweet spot of maximum speed without "porpoising" (bow bouncing up and down), but remembering to trim down before a sharp turn.

Ray

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"Knot Easy" 2000 Horizon 240 Volvo 5.7GS /SX
tow: 2017 Honda PILOT EXL-AWD
prev. boats:
'87 Chaparral 198CXL 4.3 OMC Cobra
'69 Jetstar 16ft Ski Boat, 115hp Yamaha
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PostPosted: Tue Jul 11, 2017 1:54 pm 
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Thanks Ray

valuable information which is much appreciated - will try that !

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Marbella, Spain
Vista 248 Year 2000
25th Anniversary edition
Volvo Penta Engine and Outdrive


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PostPosted: Tue Jul 11, 2017 3:00 pm 
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Joined: Wed Jul 22, 2015 7:31 pm
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Cap'n Morgan wrote:
Tabs fully extended and sterndrive fully in when getting on plane. Once on plane, trim sterndrives out and bring tabs up fully.

I feel this is incorrect usage of trim tabs, as exampled in the very article you quote from BoatUS:

Quote:
Also, get into the habit of making sure your tabs are fully retracted before pushing the throttles forward each time you go to get on plane so you don't get caught off guard by a tab-induced list. Most trim-tab manufacturers offer an auto-retract feature for this reason.


I do just this. Yes, it takes a couple seconds longer to get on plane, but the boat is in better control. Once fully settled on plane, I level the boat with the tabs then trim the drives up, in that order. Make sure you're fully settled on plane before you trim the drives as this can easily cause the stern to dig in and drag, you get into a very bow-high attitude, she's hard to control and very uncomfortable for your pax.

Trim tabs take fairly constant adjustment to keep the boat level and the ride most comfortable for your passengers. When using tabs, actuate a click or two, then wait, as the delay in response is significant (a couple seconds to settle). Repeat as necessary.

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PostPosted: Tue Jul 11, 2017 4:47 pm 
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Location: Chester, UK
On our 278 Vista ( D4-300/ DPH drive) , we deploy the tabs fully down (both sides) before trying to get on the plane. Once on the plane, bring them back up; slight adjustment as required to keep the ride level. We only trim the drive up to gain the last 5 knots or so maximum speed.The real difficulty is that the Bennet system uses 1 pump. Depending on the way it's plumbed in, either the port or starboard side tab moves quicker than the other one . For that reason we've fitted a trim tab indicator; it makes it very simple to know where the tabs are. Getting the balance of port and starboard trim tab position wrong can cause quite alarming hull tilt, so much so that it can be used to steer !


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PostPosted: Tue Jul 11, 2017 7:15 pm 
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Location: Minneapolis, MN
Our 268 with a Volvo 280hp 5.7Gi will get on plane without using trim tabs just fine when lightly loaded (2-3 people, full fuel and water, and weekend "essentials"). With a heavier load we use full down trim tabs to help get on plane, then raise them completely. Always use full down outdrive trim to get on plane. If the outdrive is trimmed up a little we have had the back corners of the swim platform catching water and causing a little bit of a shudder. If the water is calm enough at cruise I try to raise the outdrive trim by holding the trim switch for 1 to 2 seconds. I notice this will cause a 100 rpm increase and maybe 2 mph faster. I have also noticed that the fuel economy may increase by approximately 0.1 mpg, or somewhere between 5 - 10%. Book figures list our boat's fuel consumption at cruise just over 2.1mpg. We installed a Lowrance fuel flow sensor tied to a Lowrance HDS 8 chartplotter. Our boat is bottom painted. Fuel consumption has been very close to factory specs. I was surprised to see the best fuel economy at around 3600-3700 rpm. Regarding the use of trim tabs for cruising, I have noticed that with the tabs down and the engine at 3100rpm I get about 21mph and maybe 1.6 mpg. Just raising the tabs brings the engine up to 3500 -3600 rpm, the boat speed to about 26mph, and the fuel economy up to 2.0 - 2.1 mpg. The outdrive can be trimmed up higher at top end than at a slower cruise. The boat will porpoise or lose speed if trimmed up too far.

Generally you want trim tabs up for following seas, and depending on how rough the water is, there are times you may want trim tabs down some for going into seas. This is to give a smoother ride by having more of the length of the hull in the water and use the bow to break the waves. This involves some experimentation. Use a trim tab to level the boat for crosswinds or unbalanced loads.

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Current boat: '02 FW 268 Vista
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PostPosted: Wed Jul 12, 2017 10:07 am 
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Location: Lake St.Clair, Ontario, Canada
jtkey wrote:
Cap'n Morgan wrote:
Tabs fully extended and sterndrive fully in when getting on plane. Once on plane, trim sterndrives out and bring tabs up fully.

I feel this is incorrect usage of trim tabs, as exampled in the very article you quote from BoatUS:

Quote:
Also, get into the habit of making sure your tabs are fully retracted before pushing the throttles forward each time you go to get on plane so you don't get caught off guard by a tab-induced list. Most trim-tab manufacturers offer an auto-retract feature for this reason.


I do just this. Yes, it takes a couple seconds longer to get on plane, but the boat is in better control. Once fully settled on plane, I level the boat with the tabs then trim the drives up, in that order. Make sure you're fully settled on plane before you trim the drives as this can easily cause the stern to dig in and drag, you get into a very bow-high attitude, she's hard to control and very uncomfortable for your pax.

Trim tabs take fairly constant adjustment to keep the boat level and the ride most comfortable for your passengers. When using tabs, actuate a click or two, then wait, as the delay in response is significant (a couple seconds to settle). Repeat as necessary.


A lot of boats will benefit from using the trim tabs to help the boat get on plane quicker and save fuel and then you back the trim tabs off and only use some trim tab for levelling boat or for better handling of waves in rough conditions while up on plane. Some boats do get up on plane well without the use of trim tabs, but always bring your outdrive(s) in to transom when getting up on plane then raise outdrive(s) for best speed and wave conditions.

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- 25' Doral Citation


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PostPosted: Wed Jul 12, 2017 11:05 am 
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Joined: Wed Dec 09, 2015 2:23 am
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Great stuff guys...lots for me to experiment with !
Much appreciated

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Bill P
Marbella, Spain
Vista 248 Year 2000
25th Anniversary edition
Volvo Penta Engine and Outdrive


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