A heavy boat helm can take the fun out of sailing. It makes life tiring and, more often than not on a modern yacht, it’s a sign that something’s wrong.

If your yacht happens to be a 33-footer by Van de Stadt, you would expect her to be both nicely balanced and light on the helm – but that’s not what Catherine and Alex Nancekievill found with their forerunner of the Marsdiep class.

They bought Fosca Helena as little more than an unloved steel shell built in the early 1960s and spent seven years restoring her, during
which time they had two children and even sold their house so they could continue the project.

Then they put her in the water and started sailing – only to discover that she could be seriously hard-nosed.

As Catherine explains, ‘the problem is balancing the boat when the wind is on or abaft the beam. The boat helm becomes very heavy, and as she has a tiller this quickly becomes tiring. We haven’t sailed in any really heavy weather, but I worry that it could be a problem if we get caught out.’

With a young family, and an autopilot yet to be fitted, Catherine and Alex really need to make life as easy for themselves as possible: having to play tug-of-war with the tiller is not helpful.

As part of the restoration, they fitted a new Z-Spars mast, new standing rigging and a new mainsail and roller genoa from Dolphin Sails.

They have also covered a few miles between them, and it became apparent from our early discussions that ‘operator error’ was unlikely to be a major factor in this case. So what could the problem be?

Looking for clues to solve heavy boat helm

Catherine mentioned that the design drawings supplied with the boat when they bought her showed that she had been modified by the designer.

The copies she sent confirmed that the counter stern had been shortened, the centreplate removed and the keel made deeper by a foot or so instead.

A second mast step position had also been added – presumably to compensate for the change to the underwater profile – and Catherine had been unsure which to use.

She chose the forward one, though there were only a few inches between them.

Another change was that the rudder, hung on the aft end of the keel, had been brought closer to the vertical. This should make it lighter and more efficient, but the blade itself was still massive and without any balance.

It was connected to the tiller by means of a drag-link, to move the tiller abaft the rudder head and create more space in the cockpit.

On seeing the drawings, my suspicions immediately focused on the rudder.

A blade this big, without balance and controlled by a tiller, would probably feel heavy no matter what.

Even if the boat was well balanced, such a blade would take some turning. Other factors might be contributing to Fosca Helena’s heavy boat helm, but a well-balanced boat can still be a handful if the rudder lacks balance.

An imperfectly balanced boat with an unbalanced rudder will be even harder.

Boat balance and rudder balance

Boat balance and rudder balance are often confused – and the latter is not widely understood – so let’s have a look at each of them and how they interact.

Essentially, the boat’s balance means what she would do on any given point of sail if the helm were fixed amidships.

If she rounds up, it’s weather helm. If she bears away, it’s lee helm.

You can, however, have a boat whose pronounced tendency to round up is countered by a well-balanced rudder blade.

In such a situation you would have the tiller well to windward (or several spokes down on the wheel) but the helm wouldn’t feel heavy even though the rudder was being dragged through the water at a substantial angle and might be close to losing grip.

By contrast, a boat might have minimal weather helm – calling for only a few degrees of rudder angle to keep her on track – but an unbalanced rudder making the boat helm heavy.

In this latter instance, people often say ‘my boat carries a lot of weather helm’ – but they’re confusing boat balance with helm balance.

Balancing a blade

Designing a rudder with just the right amount of balance is still something of a black art despite all the science.

Even reputable designers don’t always get it right.

Disregarding mechanical friction, the effort needed to turn a rudder blade is fundamentally a factor of the distance between its pivot point and its pressure point.

The pivot point is a continuation of the line of the rudder stock, or the pintles and gudgeons if it’s hung on the keel or transom.

That leaves the pressure point, which is approximately 25% of the way aft from the blade’s leading edge.

The pressure point needs to be abaft the pivot point to create some feel on the boat helm.

Without any load transmitted through the tiller or wheel, you would find it difficult to gauge how hard you’re pressing the boat.

You might suddenly find the rudder losing grip with no obvious warning.

Some boats have rudders like this and you have to be highly sensitive to signs that they’re about to broach.

You normally expect the helm to load up first.

If the pressure point is too far abaft the pivot point, on the other hand, the result is an uncomfortably heavy boat helm. It’s like steering with an oar.

The other extreme – thankfully – is encountered only rarely: an over-balanced blade, where the pressure point is forward of the pivot.

In these instances, the blade will slam across as soon as it’s turned even slightly one way or the other.

That’s what happens when you’re manoeuvring in astern under power: if you don’t grip the tiller or wheel tightly, the rudder takes control.

Overbalancing is the last thing you want – it’s potentially dangerous.

By and large, designers err on the side of under-balancing for safety reasons. They also have to be mindful of the fact that the pressure point moves forward as speed increases.

The last thing you want is for the boat to launch itself down the front of a wave and the helm suddenly to fly hard over. That could be messy.

When a rudder is on a full-length skeg, there’s no scope for balance. Options are also limited when it’s on the end of the keel.

Such rudders will be heavier, especially those of low aspect ratio.

The higher the aspect ratio for any given area, the smaller the distance between the pivot and the pressure point and the lighter the boat helm.

Dinghy sailors with pivoting blades will know instantly if their rudder isn’t fully down because the helm will become heavy.

Some vertically-lifting rudders also provide scope to angle the blade forward or aft. Just wedging the head of the blade to move it aft by a fraction of an inch can bring the bottom far enough forward to transform the balance.

Balance in practice

With Fosca Helena, the only way to develop our thoughts any further was to go for a sail. She was based on the Orwell, but we met in Harwich for logistical simplicity and to allow us to head straight out into open water.

I drove east not knowing whether there was anything we would be able to do on the day to reduce the extent of the problem, let alone resolve it.

Here was a boat of first-class pedigree, sailed by people who clearly understood more than many owners about what makes a boat tick, and on which the rig and sails were less than two years old.

I had spoken to Dolphin to confirm the specification of the mast and sails, made contact with the Van de Stadt office, which was very helpful, and looked at the drawings.

The new rigging would have stretched and, if it hadn’t been re-tensioned, might be a contributory factor. Otherwise, the finger of suspicion still pointed at the rudder.

When we met in Harwich, Alex stepped off the boat with the children for a day of shoreside activities while Catherine and I went sailing to see what we could find.

On taking the tiller as we motored out, I found that the boat helm was indeed heavy. The barn door hanging on the keel took some turning even without any influence from wind, waves or heel.

Once in clear water, we found conditions that could hardly have been better. An easterly breeze of 12-15 knots was kicking up a moderate sea and getting Fosca Helena nicely powered up on the wind.

Another few knots would have been a stiffer test, but this was fine – and quite enough when it came to taking photos from an inflatable tender that wasn’t much longer than my lenses.

The boat helm was exactly as all the evidence had suggested it would be. When properly trimmed upwind, Fosca Helena was naturally inclined to go in a straight line and needed little help from the tiller.

When the sheets were eased, moving the rig’s centre of effort substantially to leeward of the centre of buoyancy and centre of gravity to induce a turning moment, she naturally exhibited a tendency to round up.

That’s to be expected: almost any boat will carry more weather helm on a reach. This inclination was only modest, but manifested itself in a heavy boat helm because of the unbalanced rudder.

Even in those relatively gentle conditions, sailing on a broad reach with the waves on the quarter called for more effort than would have been comfortable for any time.

In 25 knots and heavy seas, I suspect it would take all the effort even a muscular helmsman or helmswoman could muster.

Refining the rig

Given the lack of scope for doing anything about the rudder there and then, it was a matter of seeing whether we could make any tweaks to improve the boat’s balance and reduce what little weather helm there was.

Even a slight reduction in rounding-up tendency would make life easier.

As I had suspected, the rigging was far too slack – not because it had stretched, but because the yard that un-steps the mast at the end of each season and re-steps it in the spring had never tensioned it in the first place.

It’s by no means uncommon for a yard to do up the rigging simply so the mast won’t fall over, leaving any further tensioning and tuning for the owners to do themselves or arrange with a rigger.

Unless told otherwise, owners tend to assume that, when a yard has stepped the mast, it’s ready to go. Often it’s not.

Rigs like those on Fosca Helena – traditional ‘four square’ masthead rigs with tree trunks for masts – aren’t going to fall over in a hurry because they’re inherently so simple and robust.

They’re much less tweaky and sensitive to tuning than a typical fractional rig, but still need to be tensioned properly both for safety and to allow the boat to perform to her potential.

Otherwise, it’s the sailing equivalent of driving on flat tyres.

Lateral stiffness

Lateral stiffness is important with any rig, and as the leeward cap was waving around in the breeze we took about half a dozen full turns on each bottlescrew.

However, it was tensioning the backstay that made the biggest difference to the sails because the sag in the forestay had led to excessive fullness in the genoa.

A sail that’s too full means more heel, more drag, less speed and more weight on the boat helm.

It’s important to bear in mind that a heavy boat with a masthead rig like Fosca Helena will need fuller sails and less rig tension than a lighter, fractionally-rigged alternative, but floppy rigging and baggy sails are performance-killers regardless

Flattening the mainsail

One way to help control the weight of the helm off the wind would be to reduce the power in the large, low-aspect-ratio mainsail.

Catherine says she has often resorted to reefing even in moderate conditions.

We made several refinements and looked at ways of improving matters further.

These included increasing the power of the clew outhaul (which had no purchase) and making it easier – or even possible – to tension both the outhaul and the reefing pennants.

All emerged at the forward end of the boom, where they were jammed by fiddly-to-operate clutches and had no direct lead to a winch.

The position of the reefing pennants at the other end of the boom was something we could change.

They were too far forward and, therefore, not pulling the leech far enough aft, so we re-rove the first one abaft the mainsheet attachment to illustrate the difference.

Back to the rudder

Since the existing rudder will always present a problem regardless of what’s done to the rig, changes below the waterline are the only way to achieve balance in this case.

The rudder was made deeper when the keel was extended, so its area is greater than the original.

On that basis, the equivalent area could be taken off the aft edge to move the pressure point forward and create a blade of higher aspect ratio.

A more radical solution would be to remove the existing rudder and start again with a new semi-balanced blade further aft on a partial skeg and with a vertical stock.

The closer the stock is to vertical the better the blade works and the lighter the boat helm.

An arrangement like this would be vastly more efficient.

Being made of steel, Fosca Helena lends herself to this sort of treatment: mechanically it should be relatively straightforward.

Converting to wheel steering, even if it were possible, would not be the answer.

Using mechanical advantage to disguise a lack of balance would leave the fundamental issue unresolved, and the gearing would have to be so low as to call for a lot of wheel-spinning.

PBO conclusion

If a boat and her rudder are such that she can be trimmed to be light on the helm, it principally comes down to how the rig and sails are set up. In this case, more fundamental changes are needed, but they have the potential to transform the boat.

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