When to trim or not to trim?

[Bassfan99]

What are some guidelines or advise regarding when to trim the motor (not a jack plate, I dont have one) up or down? Do you basically lift it up to avoid obstacles in shallow water then run is all the way down other times?

Thank you kindly.

[J Risco]

Trim is used to get the best performance out of a boat, both speed and turning.

Tucked all the way for holeshot... then trim up to get bow lift and better running attitude. Without knowing any specifics of boat and engine hard to give exact info... but most boats will cruise best near neutral trim (engine propshaft level with pad) which should be about 3/4 or so of available trim. Some will turn good there, some will want you to tuck the motor back down a bit for best turning, every hull/combo is different. When you are running WOT trimming up a bit more will get a bit more hull out of the water to increase speed. Boats that run over 60-65 will then need to be driven or else chine walk can start.

What boat and motor do you have?

[Bassfan99]

Thanks...2015 Triton 18 TRX w/ Mercury 200

[Bullet 20cc]

Trim is used to get the best performance out of a boat, both speed and turning.

Tucked all the way for holeshot... then trim up to get bow lift and better running attitude. Without knowing any specifics of boat and engine hard to give exact info... but most boats will cruise best near neutral trim (engine propshaft level with pad) which should be about 3/4 or so of available trim. Some will turn good there, some will want you to tuck the motor back down a bit for best turning, every hull/combo is different. When you are running WOT trimming up a bit more will get a bit more hull out of the water to increase speed. Boats that run over 60-65 will then need to be driver or else chine walk can start.

What boat and motor do you have?

This is a really great explanation above and I agree completely. Trim controls the altitude of the bow of the boat. There are 3 different trim ranges...lower trims, higher trims and neutral trims. Your boat is capable of some pretty good speed at that size with that horsepower.

Lower trims will shove the bow down into the water. You would want to do that when coming out of the hole since you want the bow to lay over as quickly as possible. You also might want to do that when turning (especially sharp turns) since more of the boat will be in the water so it will grab better and be easier to control through the turn. Also if the water is very rough you want to trim down to put the bow in the water as much as possible to cut through the waves for a much better ride quality. If you are experiencing porpoising where the bow continuously goes up and down on it's own at the speed you are traveling, trimming down will alleviate that.

Higher trims will try to lift the bow out of the water. This is really only necessary for high speed running in calmer waters. When the bow is out of the water less hull is touching the water giving it a very light feeling almost like it's ready to fly through the air rather than ride on the water. Could be a little dangerous if you are not yet a good driver or if your boat was not set up properly so be careful when going to higher trims until you get a good feel for the boat and some driving experience under your belt.

Neutral trim is perfect for cruising as it keeps enough of the bow in the water for excellent stability while allowing enough of it out of the water to cruise at a little higher speed. Shouldn't need to trim much higher than this while gaining driving experience.

An example of a boat run would be...trim all the way down and apply substantial throttle til the bow lays back down (comes out of the hole), then throttle can be lightened up on a bit while motor is being trimmed to a neutral position. Going to turn...trim it back down before entering the turn and pick a throttle setting that matches the speed you want to turn at and then back up to neutral after the turn. Want to haul arse...bump trim higher than neutral and apply more throttle until things get light and loose or fear starts to set in then bump trim down and/or lighten throttle.

Always wear life jacket attached to kill switch (deadman's cord). Hope this helps...

[back_lash]

I'm sure your going to have a "driving" curve at WOT with that boat. I'm guessing its going to chine walk. Just be careful and don't try to drive too fast.

[crankbass'n]

Good intense descriptions. How does the jack plate come into play then?

[J Risco]

Good intense descriptions. How does the jack plate come into play then?

Trim will create an angle, positive or negative (unless you are at perfect neutral/level trim) that will effect the attitude of the boat.

A jack plate raises and lowers the engine on the same almost vertical plane as you raise and lower. You can control how high the propshaft (and therefore prop blades) are in relation to the bottom of the hull. Ideally you want the jackplate as high as it will go (or close to it) without losing water pressure or bow lift... that height will usually provide the best performance for a given prop.

[Midnight Rider]

Trim = Speed. You can run the boat at wide open throttle with the engine tucked under as if you are coming out of the hole and it will plow water...very inefficient. As you trim up...just bump it up a little at a time...you will gain speed at the same throttle position. As you trim up, the boat bow will begin to lift and get up on it's pad. The water spray from the hull should be behind your driving position. Once up out of the water then you can back off the throttle if desired. At wide open throttle and maximum trim for YOUR hull and setup, the boat will be totally on it's pad, with very little of the rest of the hull in the water. That's where driving skill comes into play...you have to keep the hull on the pad or it will begin chine walking which means it's falling off the pad to the right, then left, then right, etc. The bow of the boat will be moving side to side until it becomes so bad it's dangerous. Do NOT kill the throttle at that point...unless you want to be ejected from the boat...just trim back down and begin the process again when the boat stabilizes. Generally, you make small corrections when up on pad to avoid letting the boat fall off to the right. Moving the steering wheel a small amount to the left in a see-sawing motion will keep it from chining, but it is a seat of the pants thing and take time to learn. A hydraulic jack plate is not necessary for most people. A jack plate allows you to adjust the centerline of the propshaft relative to the bottom of the pad for optimum performance. The size (setback) of the plate...like 6", 8" etc, puts the lower unit in "cleaner" water, typically allowing the engine to be higher than just bolted to the transom. It also changes the fulcrum point, allowing more bow lift. But before you start thinking about doing all that, just learn to drive the boat as is, adjusting trim for speed and handling.

[A7T3C]

Others have pretty much nailed it on how/when to trim. Just wanted to give my .02 as I recently purchased a new boat and have been learning quite a bit lately with each trip out.

Take your time! Unless you’re sitting in a tournament setting (hopefully not, with a new to you boat) there’s absolutely no need to rush things. Get to know your controls, and take each hole shot and slow down as a learning opportunity. I was having hole shot issues, and I quickly learned that you need to be completely trimmed down for best/most efficient take off. As you begin to pick up speed and jump on plane, slowly start raising your trim up. When I thought I was trimmed up enough, I learned I was nowhere near actually – as my boat maxed out at a speed much slower than I knew it was capable of. I trimmed up when realizing this, and found with each adjustment of trim up my mph was rising as the hull began to settle into its most efficient place on the pad.

Each boat is unique in its own, seat time will be the best thing you can do besides research and listening to other’s input. Don’t forget a life jacket and kill switch line attached to you, shit happens – stay safe.

There’s a ton of info to be reviewed and acquired here, good luck!

[Bullet 20cc]

Good intense descriptions. How does the jack plate come into play then?

Part 1
A jack plate allows you to set the prop at the perfect height in relation to the waterline. The deeper a prop sits in the water the more grip (less slip) it will have on the water. You would benefit from a lower jack plate setting in the same areas as you would from lower trim settings...more grip needed for coming out of the hole, turning and rough water situations. The higher a prop sits in relation to the waterline the less grip (more slip) it will have. You would benefit from a higher jack plate setting in the same areas as you would from higher trim settings...higher speeds require less grip since the boat is moving across the water at a faster pace. Additionally higher speeds would benefit from higher jack plate setting from less lower unit drag since less of the lower unit is in the water on a higher jack plate setting. Your only limitation on height would be your lower unit's ability to still be able to pull in sufficient water for proper cooling of your outboard.

Hydraulic jack plates have the luxury of being able to be raised and lowered while running to satisfy all situations above. A manual jack plate cannot be adjusted while running so a height that satisfies all situations to some extent must be selected.

[Bullet 20cc]

Part 2
Another way jack plates can benefit a boat is by the amount of space the outboard can be pushed away from the boat (setback)...and they come in several different setbacks (from 4" all the way up to 15"). More leverage can be had by the trim for raising and lowering the bow by doing this...if you think of the chine (very back bottom of the boat) as a pendulum on a playground see-saw then the less force is needed to move the bow the further away from the chine you go. The limiting factor here is the actual weight of your outboard...a lighter outboard can be set back further than a heavier outboard.

As mentioned already some props will slip less than others and can be ran higher and some props slip more than others and would need to be ran lower...so the jack plate can help you tune for that also by allowing incremental height changes.

[FishinDad]

I'm new as well and one thing I read here that helped clarify things in my head is:
Throttle = Power, Trim = Speed
This is some great advice above. Thank you for asking. I was able to glean a few nuggets from the discussion about the jack plate as well.

[Bullet 20cc]

I'm new as well and one thing I read here that helped clarify things in my head is:
Throttle = Power, Trim = Speed
This is some great advice above. Thank you for asking. I was able to glean a few nuggets from the discussion about the jack plate as well.

You know I never thought of it that way but that's a pretty darn good way to say it...since low speeds and low speed manuvers/starts require lower trims. Nicely done...doesn't sound like you are new anymore...

[dnolen]

You may want to get someone that knows how to run a boat. Have them ride with you and coach you. My brother rode a long time with me teaching me when and how to do what. Seat time is a big kicker.