How to make your boat more stable in rough weather

It’s conditions like these that sort the good skippers from the bad. By good skippers, we mean the ones who are able to react to the conditions to ensure the ride back to the marina or boat ramp is as smooth and effortless as possible.

How, then, can you try and get things to go much more smoothly? There are a number of tools and techniques available to a skipper to get there.

Some cost nothing but can make a big difference in how comfortable your passage will be. At the other end of the scale, expensive options may all but eliminate any discomforts while underway.

Let’s look at the cheap options that cost you nothing before moving on to the more expensive ones.

The hull that a boat rides on can vary widely, with key characteristics able to give you some idea of how it will perform on the water.

Steep stems will be good for heading into rough water but may cause the boat to chase the bow in a following sea.

Meanwhile, a sleep-angled vee at the transom will perform quite well at speed, but the boat will tend to roll around more at rest.

It pays to talk with other owners to get a sense of where your hull’s strengths and weaknesses lie. This, in turn, will give you a good idea of how the boat should be driven in a mix of conditions.

Just like a car must drive to the conditions, so must a boat. That means you will need to choose the most comfortable speed to cross a body of water, keeping in mind that sometimes slowing down is not the solution.

Waves have a height and a period – the distance between waves. A small period means waves will be close together.

Waves without much height but a short period are okay to skim across at speed. However, a longer period may force you to slow down as the boat falls off one wave and hits the next.

In contrast, a boat with a steep bow will tend to hunt around in a following sea, making it safer to follow a wave rather than cross it. In contrast, a boat with a fine bow entry will move better in a following sea, meaning you can travel faster than the waves. 

Use the throttle like that of a car going up and down hills, speeding up on the back of a wave and backing off when running down it.

Generally speaking, whatever speed you can go running with the waves, expect to do half that pace heading into them. Running with them, be prepared to pick a wave and sit on the back of it – that’s as fast as you’re going to go.

Boats tend to be quite sensitive to load, so it’s important to get the balance right to make life onboard more comfortable.

Where it becomes important is in the boat’s righting moment, or its ability to stand back upright after it rolls in response to swell or a wave.

Weight concentrated on one side of the boat will make it behave very differently, particularly if there is wind involved – in high winds, a boat will tend to lean into the breeze rather than away from it. The effect will be more pronounced on a deep vee-hulled boat than a flatter-bottomed boat.

If the weight is on the windward side – the side the wind is coming from – the boat will lean even more into the wind and its ability to right itself is reduced. Moving people or gear to the leeward side – away from the wind – will help flatten the boat’s ride.

Likewise, moving people around a boat may help when it comes to making the ride more comfortable. Asking people to sit more aft in a following sea will help a boat that has a tendency to chase its bow, making handling more predictable.

Outboard and sterndrive engines come with a trim system that can push the lower part of the gearbox out from the boat, or tuck it back in.

The boat is very responsive to engine trim. Let the engine fully down and the boat’s nose will tuck in, punching through waves and becoming sensitive to steering. Trim out, and the bow will lift, softening the ride and making the boat feel more vague to steer.

Trim is also important for maximising fuel economy, particularly as speeds rise.  

This is where we start spending money. Trim tabs are accessories fitted to the transom of a boat that push down on the water flowing off the hull to help the boat sit up on the plane and once there, adjust the bow of the boat up or down.

The tabs can either be a flat plate extending horizontally off the transom or like a gate that comes down vertically – the latter are commonly referred to as Interceptor-style trim tabs.

Each has pros and cons – the horizontal trim tabs tend to be large and generate more drag from fast-moving water, while the vertical tabs have less drag but aren’t so good for higher speeds because of the forces they generate. Trim tabs are also very good at tangling up in fishing lines, jetties and boat trailers.

Interceptor-style trim tabs are more expensive than plate trim tabs. The simplest trim tabs use a spring, with the more sophisticated versions using actuators to finely adjust the height of the plate on each side of the boat – handy to adjust a boat affected by weight or wind while making passage.

Active trim tabs are a relatively new thing, and use sensors to measure how a boat is moving at up to 100 times a second. It uses this data to make minuscule adjustments to the trim tabs to automatically keep the boat sitting flat and level.

The result is a boat that sits surprisingly flat and level when on the move, although the system will not work when the boat is at rest.

However, the active system shines when it comes to punching into waves, helping to minimise slamming when the bow comes off a wave and lands back on the water, making life on board much more comfortable.

Gyroscopes for trailerable boats are available, although they tend to be for boats 7.0 metres or more in length.

This is the most expensive option for smoothing out the ride on a boat, coating tens of thousands of dollars rather than just thousands.

These work by spinning at high speed to create a force known as angular momentum that produces a torque that corrects a boat’s pitch and roll. The clever systems can eliminate up to 95 per cent of a boat’s movement, both while underway and at rest.

These systems also come with their limitations. If they’re water-cooled, you may need to add more thorough-hull fittings to plumb them in, they take as much as half an hour to spin up to the very high speed they need to work effectively, and they chew a fair bit of 12-volt power.

They also tend to be heavy – their weight can easily account for up to two passengers – and bulky. That’s not a problem if you can do an under-sole installation, but it may need to be installed at deck level on a smaller boat.

They’re also extra maintenance, requiring a service every 1000 hours or each year, depending on what comes first, as well as new fluids and parts every 2000 hours.

Smoothing out the ride of a boat comes down to the simple things such as understanding your boat, right up to the expensive options that will all but eliminate the factors that make people seasick.

It really comes down to whatever floats your boat. And your budget.