If you’ve ever been out on the water and felt your boat bouncing up and down like it’s trying to leap forward, you’ve experienced porpoising. Just like a porpoise breaking the surface, the bow lifts and falls repeatedly – turning what should be a smooth ride into a frustrating experience.
Porpoising is common in smaller craft such as aluminium boats, bass boats, jon boats, and jet boats. While it can feel unsettling, the good news is that it’s usually easy to fix once you know the cause.
At Power Equipment, we want every trip on the water to be as enjoyable, safe, and efficient as possible. Here’s what you need to know about boat porpoising – why it happens, and how to stop it.
What Causes a Boat to Porpoise?
Several factors can contribute to porpoising, and in most cases, it comes down to balance, engine setup, or trim settings.
1. Weight Distribution
An uneven load is the most common culprit. If too much weight is concentrated at the stern, the bow will naturally lift and struggle to stay steady.
A quick way to test this is to shift passengers, gear, or even a few temporary weights (like sandbags) forward and see if performance improves.
2. Motor Height
If weight distribution isn’t the issue, engine mounting height is the next thing to check.
When an outboard is set too deep, drag increases and the thrust angle works against the hull, leading to bounce. Ideally, your cavitation plate should be level with, or just above, the bottom of the hull when on plane. If it’s buried below the waterline, the engine may need to be lifted.
3. Engine Trim
Trimming too high (angling the motor away from the transom) raises the bow and can easily lead to porpoising. Trimming down (angling in) helps bring the bow back under control and smooths out the ride.
How to Fix Boat Porpoising
Nobody wants to slow down to stop bouncing – and you don’t have to. Here are some proven solutions.
Adjust Weight Balance
Move gear or passengers forward, or add ballast to the bow if needed. This is a quick and inexpensive fix for many small boats.
Raise the Engine
If your engine is mounted too low, raising it in small increments can reduce drag, improve efficiency, and minimise porpoising.
Trim the Motor Correctly
Experiment with trim settings. Trim down in chop for stability, and trim up carefully in calm water for speed – without overdoing it.
Install Trim Tabs
Trim tabs can be highly effective in controlling porpoising by creating lift and stabilising the hull. They do add drag, but for many boaters, the trade-off is worth it.
Fit a Hydrofoil
On smaller boats, a hydrofoil fitted to the outboard can improve stability and reduce bounce without the complexity of trim tabs.
Change Propellers
Switching to a propeller designed for more stern lift can help balance the boat and eliminate porpoising, often improving fuel economy and speed at the same time.
Final Thoughts
Porpoising usually comes down to a combination of weight distribution, engine height, trim settings, and propeller choice. Every hull design is different, so the right solution may involve a little trial and error.
At Power Equipment, we’re committed to helping you get the most out of your boating experience. If you’re still struggling with porpoising, reach out to your local Power Equipment dealer for professional advice tailored to your boat and setup.
Smooth water and steady rides are just a few adjustments away.
