What happens if outboard is too low?

If the outboard is too low, it creates excessive drag, which cuts into speed and fuel efficiency. If it's too high, the propeller tends to ventilate, losing its bite on the water and blowing out while turning and in steep seas.

How low should an outboard motor sit?

If you have a short shaft motor, the top most part of the transom and the lower most part of the boat should be about 15 to 16 inches.

What is the correct height to mount an outboard motor?

A boat rigger's rule of thumb is that the motor can be raised one inch for each eight to 10 inches of distance between the transom and prop. As the prop moves further aft, it's also likely to be in cleaner, “harder” water, and be more efficient.

How do you know if your outboard is too high?

If It's Too High

The most obvious one is an unleveled plane. When you try to plane out the boat, the prop blowing out indicates that the overboard is too high. Additionally, having less drag is a telltale sign that the motor is too high because the motor isn't underwater enough.

Where should the cavitation plate be in relation to the bottom of the boat?

The cavitation plate should be nearly even with or slightly below the bottom. For a short shaft the vertical measurement of the transom should be about 15 inches.

How to Tell if Your Outboard is Mounted Too Low

How low should the cavitation plate be?

Place your straight edge lengthwise against the underside of your hull, allowing 2′ or 3′ to hang off the back toward your outboard. Check the position of the anti-cavitation plate in relation to the straight edge. The bottom of the plate should be at or above the top of the straight edge.

Should cavitation plate be underwater?

your cavitation plate should be right at the water level. As a rule of thumb it should be 1 inch above the hull for every 12 inches back. (if you have a eurotransom, or bracket or something.) If your cavitation plate is under water you might get better performance if you raise the motor.

What causes outboard motor cavitation?

Cavitation could be caused by badly placed transducer or through hull fitting. A hollow in the hull (also called a hook in the hull), worn/bent Propeller. From initial start – to get onto the plane, the engine seems to rev a lot but the boat stuggles to get up on the plane, you could have cavitation ventilation issues.

What is porpoising in a boat?

Porpoising is a sustained, repetitive motion that causes a boat's bow to bounce up and down out of the water, even in calm waters. While porpoising can be merely uncomfortable for passengers, it can also cause loss of control, which may result in injury or damage to the structure of the boat.

What happens if your outboard shaft is too long?

If you went too long it would still work but it may lack in performance. You will also risk hitting bottom or submerge objects more frequently such as rocks or logs. If you go too short your more than likely going to cavitate and loose power.

Do Trim Tabs help get on plane?

Properly sized trim tabs can significantly reduce the time needed to get up on plane. They also allow a boat to keep its bow down and stay on plane at lower speeds.

What does transom height mean?

The transom is the flat vertical section at the rear of the boat. It is where the outboard is mounted, and some boat owners place the name of the boat. The height of the transom is calculated by measuring from the bottom of the hull to the top of the transom, using the center line.

What do transom wedges do?

Most cases they are used to provide negative trim, for when your bow will not come down enough due to the angle of the motor (transom is built without enough of a negative angle). This is a quick, cheap and effective fix!

What causes a boat to hop?

Does your boat 'bounce' when you reach a certain speed on the water? Known as porpoising, this phenomenon typically occurs when a boat is traveling at a high rate of space with the incorrect trim setting. Normally, porpoising is prevented by making the necessary trim adjustments.

When should I trim my boat down?

Start with trim down: When you're taking off from displacement speeds, most boats work best with the engine and bow trimmed down — this helps the boat rise quickly onto the plane. However, once your boat is on plane, it's important to adjust the trim based on the sea conditions.

What is chine walk?

What is chine walking? The chine walking experience refers to the situation occurring with high performance vee-hulls as the boat accelerates, lift increases and the running surfaces raise out of the water.

Why does my small boat porpoise?

Why Do Boats Porpoise? A boat can porpoise because the weight in the boat is disproportionate between the bow and the stern. It might also be because of the trim angle of the engine and the mounting height of the engine difference.

What causes a boat not to plane?

The most common are overloading and failure to distribute weight properly. Another major cause is incorrect tilt of the outboard motor, which changes the angle of the hull relative to the water surface. If the motor is tilted too far aft, the propeller will dig into the water and force the bow up.

Why does the front of my boat go up?

Porpoising, or the bow bobbing up and dow, is caused by over-trimming at cruising speed; there's no longer enough hull in the water to support the weight of the boat. Either trim down a little until the porpoising stops, or increase boat speed slightly to create more lifting force under the hull.

What is the purpose of a jack plate?

What is a Jack Plate? Similar to a setback, a jack plates also add weight and some distance (typically much less) between the engine and transom, but the primary goal of this feature is to raise and lower the engine within the water.

What does a Permatrim do?

The Permatrim extends out past the end of the cavitation plate, to catch the wasted water from the top of the Propeller (the hump of water out the back), holding this water down and forcing it rearward, this increases the stern lift and thrust from your outboard/sterndrive from the same amount of rpm.