How do you trim?

Pmt133

Master Chief Petty Officer
Joined
Jan 6, 2022
Messages
862
Let me preface this by saying I'm very bored and mostly just curious as I found it odd... and I'm not asking how to trim a boat nor am I going to go in depth on procedure... just a general outline: I've always done it the same way and it's how my boat responds best. Drive full down, hammer down, once the boat is out of the hole (bow levels out) trim up to best performance. Any boat I've ever run that always was the best way to do it... then 2 weeks ago I was talking to a friend and he said his plows if you do that and doesn't react well... curious I asked him his procedure and he said he trims to his running angle then hammers down and it just pops up. He then leaves it alone...

I didn't think anything of it until I was talking to a few other people and they said they do the same thing. Both those boats are quite large by comparison to mine and both have a ton more power than I do as well as weight. I know if I do that on mine I get a lot of bow rise. Does come up on plane albeit slower. I know this because I've slowed down below planing speed testing props to see how they react if you dump then try to come back on and they all did the same thing. Some more than others but all did it. I am going to assume a heavier nose may also effect it.
 

bajaman123

Petty Officer 2nd Class
Joined
May 6, 2009
Messages
107
To each his own I suppose, but the MECHANICS of it demand full tuck in/trim down, hole-shot then gradually trim up and throttle back...generally speaking. Some hulls may react differently obviously.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
50,936
Drive / motor full down
If there are trim tabs, leave them down slightly
Mash the throttle, as the boat starts coming out of the hole, thumb up on the trim.
The boat should be out of the hole and the bow should start raising
Once it starts porpoising, tap the down trim twice with your thumb

As you pull back on throttle.... Thumb down on the trim for the next holeshot
 

airshot

Vice Admiral
Joined
Jul 22, 2008
Messages
5,651
Every boat will be different, also how weight is distributed and boat size. Neighbor's 22' Sylvan alum needs barely any trim adjustment, it just jumps up and shoots out on plane. A slight touch adjusts the bow to match wave heights. My 16' Sylvan alum, reacts very well to small inputs, gotta be careful so the prop doesn't vent. I typically watch my tach, trim up until a slight vent then bump it down a click. Typically gain 3-400 rpm and 3-4 mph with just trim adjustment.
 

ratdude747

Petty Officer 1st Class
Joined
Sep 30, 2023
Messages
377
Depends on the boat.

I'm lucky... my Starcraft Montego (with a 302 mercruiser and a whale tail on the outdrive) doesn't need trimmed when running- just leave it down and run. The only time I trim it is when in shallow dock water. I'm told before the previous owner put the whale tail on it was always bow-in-the-air and very hard to get on plane (especially with the original high-speed low-torque prop)... how much those changes had to do with the lack-of-porpoising with trim all the way down I couldn't say.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,328
Some boats will ventilate if you trim them at idle and then accelerate. This is especially true for boats where their outboard motors are mounted high for less drag/higher speed.

When my Merc 135V6 was mounted high on the jackplate, it needed to be trimmed all the way down to accelerate at all. Once on plane, you could trim her a lot, for top performance.
 

jlh3rd

Senior Chief Petty Officer
Joined
Jul 10, 2017
Messages
723
pontoon boat: I trim for max speed/rpm/ neutral wheel feel at whatever rpm I'm running.
 
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