Sometimes all of the different terms that are used in the marine industry and in the boating community in general. It can get a little confusing and overloading. We get the question quite a bit.
What’s The Difference Between Boat Trim Tabs & Tilt & Trim? Trim & Tilt is the system on the boat’s engine that moves the engine or the drive unit up and down. Where trim tabs are a system that is mounted on the boat to assist the boat in adjusting for weight inside the boat. As well as water current and wind, the trim tabs will adjust the angle of the boat going through the water.
This article covers everything you need to know about what makes these two systems different and how each of them operates!
What Are Trim Tabs?
Trim tabs are a system for keeping your boat level while moving through the water. Trim tabs are plates that are placed on both sides of the boat’s stern. They are connected to hydraulic or electrically controlled rams. Also known as trim tab actuators.
These rams can push the plates down, which pushes the water down. Thinking about this with some high school physics. Every action has an equal and opposite reaction. When the water goes down, it pushes that side of the boat up.
This will lift the stern side of the boat as you continue to drop the tab. It will also push that side of the boat’s bow down as well. You can run the tab up and down to level out the boat as much as you need.
When the trim tab is pushed down, it will also create a drag on that side of the boat. What this will do is it will also pull the boat to that side. Or in other words, it will make the boat turn in that direction. Whether you are using the port or starboard tab.
Some boats come with self-leveling trim tabs or smart tabs. These use a spring instead of a hydraulic or mechanical ram. These are best suited for a boat that needs to have a constant lift from the back. To push the bow down.
The disadvantage of this automated system, however, is that you cannot control it when you want to. It basically operates on its own accord.
What Is Tilt & Trim?
The tilt and trim of the engine, on the other hand. It is used to move the engine up and down in the water. When the boat is stationary in the water and the propeller shaft is parallel to the water surface. This is called neutral trim.
While underway, when you trim the engine up some in the water. The propeller shaft will point downward, into the water. The force of the engine running the propeller pushes the stern down. Which in-turn lifts the bow up. This is a case of trimming up.
When you trim the engine down, the propeller shaft is pointing upward, towards the bottom of the boat. This lifts the stern up and pushes the bow down. This is what boaters call trimming down.
A simple way to remember this is Trim up, bow up. Trim down, bow down.
Don’t They Both Do The Same Thing?
You might be thinking to yourself, “Don’t they both do the same thing?” The short answer is yes. In the physics aspect of it. You use both of these different systems to trim your boat. However, the way in which these two systems help trim your boat is very different.
Tilt and trim on the engine uses the angle of the propeller to bring the bow of the boat up or down. You have more control of the height in which you get the bow.
Whereas trim tabs use plates that push the water and bring the bow down only. You cannot use trim tabs to push the bow up when they are in their neutral position.
Another difference is that you can use trim tabs to compensate for an uneven load. Whether you want to lift the port side or starboard side up. Whenever you have more people or gear on one side or the other.
However, trying to use tilt and trim to do this, you have a very limited amount which you can correct.
Trim tabs are also more effective at holding the bow down when in rough waters. If the boat bow is too high, affecting your vision. You can simply use the trim tabs to push it down and have better visibility.
Almost all boats with outboard motors have tilt and trim. However, there are some boats that do not have trim tabs installed. You can usually have them installed though if your boat needs them.
This goes the same for inboard boats too. If you need them, most of the time you can get them put on.
Here’s a great article we wrote on The Differences Between Inboards and Outboards!
How To Trim A Boat With Trim Tabs?
This is especially useful to get your boat on plane faster too. When planning out a boat, the bow will rise up into the air. Reducing the driver’s bow-side visibility.
Trim tabs help to alleviate this problem by pushing the stern of the boat up and leveling it out.
Once you are on top of the water, you can take the drag away by pulling the tabs back up. This will lift your bow up slightly out of the water. Since less surface area of the boat is in contact with the water.
There is reduced drag and the boat can take off in speed. This way, the efficiency of the boat increases as it has to burn less fuel with less drag.
Another useful application of trim tabs is to compensate for uneven loading on the boat. Trim tabs are able to be independently controlled. Which means they can lift either starboard or port side of the boat.
Say you have more passengers on board or you have some cargo aboard that is making your boat lean to the port side. (There are other reasons that a Boat Will Lean Or List To The Left Or Right, but we cover that in that article there.)
Rather than have your passengers or cargo shift to try and balance the boat out. You can simply lower the trim tab on the side that is lower than the other. This will push that side of the boat up and make it level with the water.
This is also effective in windy conditions when the wind is forcing your boat to one side or the other. You can use the trim tabs to put some drag on the windy side. Making the boat pull into the wind, which will straighten out the ride.
How To Trim A Boat With Tilt & Trim?
When planning out the boat, you don’t want to have any trim in the engines. Getting your boat on plane requires that you have trimmed your boat appropriately.
When starting to take off, you want to have the engines trimmed down. As you increase the throttle and speed, the bow will go up on its own. So you don’t want to have the engines trimmed up or you might not be able to plane out.
As the boat gathers speed, the bow will gradually begin to go down. Once the bow is down, you are on plane and you can trim the engines how you would like to. Trimming the engines while on plane will push the bow of the boat out of the water.
Making less of the boat for the engines to push through the water. This will increase fuel economy because the engines will have to burn less fuel!
When you trim up too far though. The boat will start “porpoising.” This is a term uses to refer to boats that are bouncing up and down at the bow. When you start to experience this effect. You should know you have trimmed up too far and should go back down some.
Trim down in small bursts, taking breaks between each burst to see if the porpoising has subsided. Keep going if it has not, but once it stops, you can stop as well.
The point at which the porpoising stops is the most efficient running angle of the boat.
At this angle, the RPM of your boat will jump up on its own and you will be burning less fuel!
You should never trim your boat up too far. The engine will start sucking in air, and begin to overheat. This will lower your boat’s fuel efficiency. As well as potentially causing damage by burning up the impeller, thermostats, and other components.
The best way to tell if you have trimmed too far up is to look at your engine’s water stream. If it isn’t ejecting water out in a constant stream, you might have gone too far. Another way to tell that this is happening is to listen to the engine itself.
If it is sucking in air, it will begin “cavitating” and cause the engine noise to increase. Some boat manufacturers even include a water pressure gauge of the engine in the console. If this pressure drops lower than normal. It might be an indication of air entering your engine cooling system.
If you still keep driving your boat with too much trim, this could permanently damage your engine.
Should You Be Trimming Up Or Down Or At All In Rough Water?
We do not recommend you take your boat out unnecessarily into rough waters. This is where your own personal discretion comes in! However, the weather can change quickly in deep waters. And the time may arise when you find yourself stuck in rough water against your plans.
For these cases, it is important that you know what to do to keep yourself and your passengers safe.
Whenever you find yourself driving in rough water, the number one rule is to be safe. This means that you keep your lifejacket or PFD on at all times. Also, you’ll want to attach your Boats Killswitch To Yourself before driving.
Getting caught in a storm is no fun! Especially when it turns into a lightning storm. You should read this article to Find Out If Boats Can Be Struck By Lightning!
Now that we have talked about safety though, we can talk about the trim. Most boats have a sharper deadrise in the front and are flatter in the back. When driving into rough water, it is a good idea to trim down.
This allows your boat to better cut the water. However, some variations are there depending on which direction relative to the wind you are going. As well as wave conditions. You don’t want to be planned out a cruising across the tops of the waves!
And you don’t want to have your trim tabs down, pushing the bow down into the washes. Causing the water to come over the bow of the boat!
Cruising upwind, (or against the wind), is the easiest of the three. The thing to remember here is to keep your engines trimmed down. Otherwise, your boat might start to “porpoise”. However, you do not want to trim down so low that your boat spears the wave.
Finding the right spot is essential. Trim your boat down just enough so that it is not bouncing up or down. And keep the bow of the boat pointed into the wind and the oncoming waves. So that your bow can cut through the water.
Going downwind in rough waters can be very difficult. When you are going with the wind in rough water. The wind will bring your boat’s bow down. If you don’t compensate for this, you are certain to spear the waves and drown your boat!
Keeping your boat level in rough water is essential. In this case, to compensate for the bow going down. You are going to want to keep the engines trimmed down still. However, you will need to play with the speed of the boat.
You will be looking to not have enough speed that you are pushing the bow into the wave in front of you. At the same time keeping enough speed to keep the following wave behind you from overtaking you.
Once you find the right balance, stay on top and in between the waves, and simply skip over them one at a time.
When the waves get bigger, it becomes extremely difficult to skip over them. In this case, you should slow your boat down. Pick one wave and stay on top of it until the end!
Going Across the Wind
When you go across the wind, you will find that you are taking in waves on the side. There is no escaping this; but you can minimize the amount of water your boat takes in by lifting that side of the boat using the trim tabs.
The trim of your boat will decide if you have a relatively smooth ride or if the waves are slamming against your boat. Try to keep it slightly down without running the risk of spearing waves.
When driving in a crosswind situation in rough waters. You will find that the space between two waves is relatively calm. You can cruise on down between the waves without taking any water.
Just turn the boat slightly so you are going a little downwind. This will prevent you from having to break the waves and allow you to have a smoother ride.
If the water gets too rough though, you want to slow your speed and work back and forth between going either downwind, or upwind. Then crosswind for a little while to keep halfway on course. Just riding out the storm until it calms enough for you to get straight back on course!
Now that you know all about trim tabs and the difference between them and tilt and trim. Here are some other articles from our website that will teach you more about your boat and boating!
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