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 causes boat Porpoising?

What Causes Porpoising? Porpoising is the result of the motor's outdrive pushing the boat upwards, essentially boosting it out of the water – albeit for a short period of time. Once the boat comes back down, the outdrive will once again push it back out of the water.

How do you stop an aluminum boat from Porpoising?

Slow your boat down. Porpoising begins as you motor picks up speed and raises your boat's hull from the water, reducing the amount of hull in the water -- which means there's too little hull in the water to support the boat. Trim the motor down until the boat stops bouncing.

How do you make a boat not a porpoise?

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.

How to Stop Porpoising

How do you know if your outboard is too high?

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. “If the prop consistently ventilates when heading down a steep wave, the outboard is probably set too high,” says Dean Corbisier, advertising and public relations manager for Suzuki Marine.

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.

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.

Should you leave your outboard up or down?

It's best to tilt your outboard up when leaving your boat in the water to prevent marine growth from forming and from corrosion eating away at its metal parts.

How do you stop a bass boat from chine walking?

NEVER chop your throttle quickly to stop chine walk. SLOWLY reduce throttle while trimming down to dampen and then stop the chine.. As you lower your nose, more of your keel is in contact with the water and begins to dampen the chine progressively from the rear of the boat to the front.

Why does my boat pull hard to the right?

The more blades in the water, the more force you get. You have more contact with the water and can force more water than with only three blades. So if you have a four-blade prop, the pull will be harder because you have more torque with that four-blade prop.

Do float pods help with Porpoising?

If they are positive flotation pods and submerged/at water level when planing then they should add stability and not lead to porpoising.

How do you trim a boat in rough water?

When learning how to trim a boat in rough water, you will need to lower your trim tabs by using the trim tab switch at the helm. Trim tabs are lowered in order to bring your bow down when operating at a slower speed in rough waters.

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.

How far below the hull should the prop be?

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. For a long shaft, I think 20 to 21 inches is correct. Some mornings it just doesn't seem worth it to gnaw through the leather straps.

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 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 rooster tail on a boat?

Rooster tail is caused by a combination of Prop slip and motor height. If you motors are surfacing you will always have some small rooster tail.

How deep should my prop be in the water?

Determining the proper trolling motor shaft length is one of the key aspects of finding the right motor for your boat. It will help ensure that the motors' shaft is long enough to keep the propeller submerged at least 12" below the water line in your specific fishing conditions.

How do I know if my outboard is mounted to low?

You can often tell that an outboard is too low if you are experiencing sluggish speeds, poor handling, excessive spray, porpoising, or even water pushing up into the cowling. That's a very brief, basic accounting of symptoms, but you'll usually find at least one of these symptoms if your motor is too low.

What does a cavitation plate do?

Cavitation plates are mounted to the lower units of boats to help increase performance. They act as a planing surface to get your boat on top faster. They give you better bow response when trimming your motor. They keep water down at your prop and intake improving water pressure.

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.