getting on plane

[torcano]

What is the consensus about putting the trim tabs down to expedite getting on plane? I asume the optimum setting is by trial and error. I also assume they should be retracted once on plane. Comments?
RK

 

[JoeCrow]

Re: getting on plane

Smartabs take all the guess work out of the equation
But when down, tabs should get you on plane faster and at a lower speed

 

[Geo2008]

Re: getting on plane

What is the consensus about putting the trim tabs down to expedite getting on plane? I asume the optimum setting is by trial and error. I also assume they should be retracted once on plane. Comments?
RK

I start out trimmed all the way down, tap it up just a hare during the hole shot, trim about half up to be perfectly on plane.

 

[dingbat]

Re: getting on plane

Keep in mind that the more tab you put into the water the more drag you create and the more drag you create the more fuel you?ll consume. Anything more than just a few degrees past neutral (tabs slightly beyond parallel with the water) causes excess drag which increases fuel consumption and may actually increase you?re planning time.

When setting my tabs I push the buttons and count one thousand one, one thousand two, one thousand three. That?s my base position for the day. I don?t touch them again until I?m up on plan and even then its not a given that I need to do anything more. I may drop them a bit to push the bow down to run rough water or I may add a little tab on one side or the other to level out the boat when running perpendicular to a tide.

Other than that it?s a concerted effort to minimize the amount of tab I have in the water to maximize my fuel efficiency.

 

[QC]

Re: getting on plane

Smartabs take all the guess work out of the equation

This is a 29 footer we are talking about here. Smart Tabs are not in the equation . . .

With a boat this size you may have quite a bit of positive tab at almost all speeds. Not going to know without running her. I would not try to apply any standard rules. With that said I am going to guess that you could use 100% to get her on plane and then bring them up some depending on your speed. If you are running in the low 20's you may keep them 100% down and then maybe have 0% if she reaches the high 30s . . . The speedo will tell you what to do. If more tab slows you down, well then . . . If less tab speeds her up, then you are saving fuel. It is not automatic that less tab will save fuel though, this is only the case if less tab speeds her up. More speed for the same throttle setting is fuel economy.

Absolutely use them for controlling list from weight shifting, wind, current whatever . . . Also, you may not get anything from positive drive trim. You are going to have to play with both. This is a big boat . . .

 

[torcano]

Re: getting on plane

Thanks for all your comments. QC, when you say "use 100% to get her on plane", I assume you mean 100% in the down position (bow down). I usually run the boat between 3500-3800 when I'm on plane which gives me 25MPH. I never run WOT unless I have to for some reason. I will play around with the settings and look at the effect on the speedometer but are you suggesting that I might run with my trim tabs full down for my usual planing speeds? I always use the tabs to trim for list due to weight or winds. My previous boat was a 24 foot Sundancer with a 8"6" beam. This boat has a 10" beam and does not list anything like my previous boat. What are your thoughts on the Bennett auto tab that uses a computer to automatically adjust the tabs to maximize efficiency
RK

 

[QC]

Re: getting on plane

I saw your other post above and will comment on the Auto tab there. Yes, it is possible, that 100% down will help at 25 MPH, but unlikely. I also doubt that all the way up will be best, but the Speedometer will tell the tale . . . Don't touch the throttle and play with different tab settings and give her a minute with each change to settle and see what point is fastest. That would be the only way I know how to answer your question. Also, needs to be done with typical load in typical locations on the boat, water, fuel, people and stuff . . .

I have run planing hulls of that size with twins and know that it is not as simple as up is fastest. Same with drive trim. Just not as responsive and not as cut and dried. Need to try a variety of combos and small changes will not be very evident. Some positive trim on the drives (up) and some up on the tabs, but not much of either is my experience with speeds in the 20's . . . I am going to email a guy we see around here some that has the same boat. Very experienced although he is running his near 60

 

[Reel Poor]

Re: getting on plane

Sup QC, got your email and thought I'd drop in and see whats up in here.

First, I would like to know what year the boat is, what engine and drive package your running in that boat, does it have a generator. and what is the wide open throttle rpm. From the numbers you gave above (3500-3800 @25mph) I would guess your running twin V-6's.

 

[QC]

Re: getting on plane

Hey Dude . . . take a look at his sig ^^^^ 2004 with 4.3 MPI Mercs. I am guessing Bravo 3s . . . Things around here have been good, but we miss your help.

Torcano, when I mentioned a little positive trim on the drives I mean from full down. I am guessing that you won't even be able to get them level, so technically they will still be down some, but slightly up from all the way down . . .

 

[torcano]

Re: getting on plane

Thanks again. My boat does have the twin V-6 but with the alpha 1 drives. I usually trim the sterndrive out a little once on plane and there is always a noticiable change with the bow bumping up a tad and slight increase in speed. In terms of technique, the question I was asking is when trying to get on plane from idle speed, should I place the trim tabs in the full down position before applying full throttle or only partially down? My thoughts were that in the full down position they might cause too much drag and actually make it harder to get out of the hole. BTY, I think my WOT RPM is around 4500RPM

 

[Five O'Clock]

Re: getting on plane

when are your trim tabs fully retracted (level with the bottom of the boat reducing drag)? when the tabs are fully "bow up" or "bow down"?

 

[QC]

Re: getting on plane

Neither ^^^^ full up should be slightly above the angle of the bottom and full down should be significantly down. The answer, Torcano, is still based on your experience while going. I would start full down, mash the throttles and bring slightly up once she starts to plane. In all cases for me, full down decreases planing speed . . . That includes my 23 footer that runs near 60 and has massive tabs which you can see below my starboard swimstep:

The point being that if planing speed is reduced then time to plane is also reduced, from that point forward bringing the tabs up does help to increase speed and reduces the tendency of the tabs to force the bow down. So I would use 100% down tab to get up on plane and then start bringing them up some as soon as I felt she was actually up on plane.

Another little tip for you is to look at the wake. I have noticed that when tabs are applied down more than necessary I get a rooster in the middle of the wake about 30 - 40 ft. back. When I pull up the tabs that rooster will eventually flatten off. See if you can pick up visual references to good speeds and tab placement. May be helpful, but ultimately most of your questions will be confirmed by trial and error . . .

 

[torcano]

Re: getting on plane

Very helpful. Thanks QC. I'll be out there tomorrow trying out all the various settings.
RK