Going astern with twin, long and fin keels

Back in the 1920s, W O Bentley was reported as suggesting to Ettore Bugatti that the Italian’s racing cars had lousy brakes. Quick as a flash, Bugatti responded, ‘I make my cars to go, not to stop!’ I’ll bet if you’d complained to any of the great designers of the past about their boats being unpredictable backing out of a berth, they’d have retorted with, ‘Who on Earth wants to go astern? My boats are meant to sail sharp end first…’

Times have changed. These days, many of us are stuck with marina pontoons that demand some degree of manoeuvrability astern, and Mediterranean sailors can find themselves backing up to the quay on a daily basis. It was one of these sunshine readers who kick-started this article. Following our stern-to mooring feature a few months back, the postbag bulged with comments such as, ‘All very well dealing with pickup lines, but how can I be sure of arriving stern-first without ending up looking a prize dunce?’

This reminded me of one or two personally embarrassing events and I thought of the number of long-keel yacht owners who’ve said, ‘My boat has a mind of her own.’ There was a job to be done here, so Perry from YM organised three very different yachts, I climbed into my boat-handling boots and joined him on the Hamble.

The theory

Steering

The secret of remembering which way to turn the helm going astern is to imagine you can see the rudder, then point it the way you want the stern to swing. So long as you’re looking astern, this makes the process logical.

Doing the job with a wheel is exactly the same as if you were driving a car. Forget about port and starboard for a moment. If you want the stern to go to your left as you are looking, wind the wheel left and you can’t do more. Ideally, the trick is to site yourself forward of the helm so it’s between you and where you are going. If you can’t manage this, at least sit or stand abeam of the wheel. That way, you can’t get your trousers in a twist.

With a tiller, just remember that it is an extension of the rudder. Imagine the two in a rigid straight line, pivoting in the middle. To move the rudder so that it points left and takes the stern that way, you’ll have to shove the tiller to the right.

Whatever you’re steering with, there is often a serious time-lag between pointing the rudder and getting the response you’re after. Indeed, the boat may continue to go the wrong way for quite some time. Don’t panic. Hang in and wait. If it’s going to happen, it will in the end. If it isn’t, you’re done for and you’ll have to think again. Wiggling the rudder will not help.

Propwalk

Most propellers come with an inbuilt tendency to take the stern one way or the other, especially with the engine running astern. The majority are said to be ‘right-handed’, which means that, looking from behind, they are revolving clockwise when going ahead. You don’t really need to know this, however. The important thing is what happens when the engine is thrown into astern. A right-handed prop will cartwheel the stern to port, a left-handed, vice-versa. Before you can expect to steer a yacht astern, it’s vital to know which you have.

Underwater profiles

One reason why traditional long-keeled yachts steer so sweetly on passage is because they have a lot of draught aft and less near the bow. Going astern, the situation is reversed and it does them no favours. The position is often similar, though less destructive, in yachts with a long fin and a rudder hung from a skeg. Boats that are essentially flat-floored with a bolted-on keel and an unsupported spade rudder don’t suffer from these drawbacks. They often steer almost as well going astern as ahead. The situation is even easier if they have a vertical trailing edge to the rudder, which many do. Their only failing is that, with little or no appreciable draught at the bow, they can be subject to blowing around uncontrollably at speeds too low for the rudder to bite. The only sure way to combat this is with a bow thruster, and we’ll look into these in the next issue.

The weather, the boats

We joined our boats on a cold November day with the wind blowing straight down-river at Force 6. Warsash Maritime Academy had kindly fixed us up with its 26ft Westerly Centaur, Tormentor. This classic Morris Minor of the sea has bilge keels. So far as I was concerned, her performance astern was a blank slate. Next, we had reader Ken Munn, who gave us a couple of hours en route to his winter haul-out so we could sample his long-keeled 28ft Twister, Indigo, design in 1963. Lastly, the time-share  charter company, Sailtime loaned us a brand-new 43ft Bénéteau, Sailfin.

The tests

There seemed little point in trying to thread all these boats into awkward berths. In the real world, every pontoon is different, so an infinite shading of technique is required. I’ve found that so long as I keep my head and remember the essentials, I can usually see what’s needed for a specific situation. To fish out these basics, we analysed the performance of all the boats with three tests.

The natural tendency of most sailing craft left to free-float in open water is to settle with the wind abaft the beam. From here, it doesn’t take much to pull the stern up towards the breeze and keep it there, so almost any boat will motor astern upwind. Try going astern downwind, however, and the bow will attempt to blow off to where it really wants to be. It takes a manoeuvrable yacht to overcome this at low speeds.

So here’s test 1:– motor downwind astern and see how fast we need to go in order to beat the propwalk and the wind.

Tests two and three relate to manoeuvring across the breeze, and the same principles hold good. One way, the propwalk will be taking the stern upwind, the other, downwind. The bow is trying to blow downwind in both cases so, if the propwalk is exaggerating this, the rudder has a lot of work to do. If the prop is fighting the bow’s natural desire to blow off, you’re in with a good chance of quick control. The exercises, then, are to motor astern across the wind, first with the propwalk trying to keep her in line, before sampling the effects the other way, ‘against the prop’, as it were.

The Centaur

Finding the propwalk

The 26ft Centaur had the original 25hp Volvo. In her day back in 1968, this was a huge engine and it still pulls her along powerfully. To discover the propeller effects, we secured her alongside then ran the motor astern. Immediately, we could see a lot of prop-wash welling up on the port side, and much less coming out to starboard. Given a chance, the stern will tend to shy away from the net turblence, so this boat obviously kicked her stern to starboard, not port as is more usual. She had a left-handed propeller. Just to make sure, we took her out into the river. Moving slow ahead, we threw the engine hard astern and noted which way her bow swung. Sure enough, it cartwheeled away to port with her stern swivelling to starboard.

The tests

Upwind and downwind

With her stern pointing upwind, the vintage Westerly kicked it a little to starboard as we put her into gear, but she soon accelerated to around 2 knots, which was plenty for her rudder to take charge, and away we went, steering at will.

The story was not dissimilar with the stern facing downwind. She had enough grip on the water to hold her position as we lost headway, but her bow swung off positively as we started going astern. However, I’d given her a sheer to starboard so we’d a bit of slack in the system, so to speak. By the time her propeller had dragged her back head to wind, we were steering sweetly at that magic 2-and-a-bit knots.

Cross-wind

Caption

With the breeze on  the starboard bow, the boat was trying to swivel her head downwind to port. As the other half of the equation, her stern would be tending to swivel to starboard. This, of course, is also where the propeller will try to take Centaur’s transom. I expected trouble, but I didn’t really get it. As I put the power on, she swung round until her stern lay about 50 degrees toward the wind as she accelerated steadily. Once up to 2.5 knots, the rudder had taken charge and she pulled back into line. Pretty good, I’d say!

Crossing the river with the wind on the port side, the propeller levered against the bow as it tried to fall away. In no time the little boat was steering like my old car in Tesco’s parking lot. Beautiful.

Setting up a sheer

When a boat has notable propwalk to one side, try giving her a tweak in the opposite direction before you start going astern. The first kick of the prop will then be used up pulling her back into line, giving you a better chance of ‘catching her’. If you’re port-side-to with a right-handed prop and you must leave astern, you know that when you start off the propwalk will graunch the quarter into the dock. The answer is to give the blunt end a kick out to starboard against a bow spring before you let go. With luck, by the time you have enough stern-way on to steer, she will have just pulled herself back into line.

The Twister

I had been fearing that Ken’s lovely Twister would be trouble, but he shrewdly said very little as I started trying her out.

Finding the propwalk

Secure alongside, we slipped the Twister’s engine into astern and waited for what seemed an age while the small one-lunger overcame the inertia of a serious flywheel. There was some evidence of a right-hand propeller, but not a lot. The real significance was that this boat was going to take quite a while to gather way, which could leave her a victim of whatever wind was blowing.

The tests

Upwind and downwind

I began with the stern up-wind ‑ the easy one – and was confounded when the Twister wandered all over the river. To be generous, she remained under what might pass for some sort of control at a drunk’s wedding.

‘Bow upwind, forget it,’ I thought, and I wasn’t disappointed

Cross-wind

Beam-on with the wind on the port side was the washout that was now predictable. With the starboard side onto the breeze, I couldn’t believe that I wouldn’t be able to control this delightful yacht with her right-handed propeller pulling her into line against the wind on the bow, but the Twister would have none of it. By the time she’d gathered enough way to be in with a chance, it was far, far too late. In a lull, we contrived a sort of compromise at revs low enough to generate only minimal propeller effect, and when we popped her out of gear altogether and let her way carry her, she did improve, but only a little.

‘Time to come clean!’ I thought, and asked Ken if he had a secret.

Dealing with a difficult boat

‘There isn’t a secret really,’ Ken said laconically. ‘I’ve tried it all.’

With its heavy flywheel and small capacity, Ken’s engine takes so long to rev up that he’s more or less given up hope of a result in any strong wind. Fortunately, this potentially world-girdling cruiser is only 28 feet long and she’s very handy. He can usually either warp her in and out of an impossible berth, or somehow contrive to wind ship so she’s pointing where she should be. If all else fails, he knows that the breeze is king and will take her bow where it wills. So long as he doesn’t fight the inevitable, he enjoys a surprisingly quiet life.

The lesson we learn from Ken’s prudent seamanship is that if a boat is unwilling, don’t try to force her against her natural tendencies. Accept her for what she is, be grateful for her other fine qualities, and find ways of living with it.

Keep control

Once a boat is moving fast enough to steer astern, her rudder can take charge very easily. If you let it, it’ll ram across right to the bump stops, and woe betide any poor soul stuck between tiller and coaming!  At speed, keep it firmly near the centre. Getting under way, make sure it doesn’t take charge. Wheels are less dramatic, but the same applies. It isn’t hard to break a wrist between the spokes when 5 tons of yacht spins the helm hard over!

Box ends

The Bénéteau

Finding the propwalk

This beamy modern yacht had so much body aft that it wasn’t so easy to observe the prop wash in the berth as on the other two boats. It did suggest a kick to port in astern and experience told me she would almost certainly have a right-hand propeller. We checked this out on the river by throwing her half astern at low speed and watching the bow. Sure enough, it slid off to starboard as the stern swivelled to port.

The tests

Upwind and downwind

After the classic small cruisers, our Bénéteau seemed seriously big. In theory, however, she had all the hull and engine characteristics to make her a good performer astern, and so she proved. Upwind and down, she accelerated so rapidly that her barn-door rudder took charge of the propeller at the usual two knots, but so little time elapsed in getting there that her bow had not blown away appreciably.

Cross-wind

Across the wind against the prop, the Frenchman fell off like the two smaller yachts, but when I gave her the gun she gathered enough way to sort herself out in what seemed like no time and. I didn’t feel any temptation to feed in the power tentatively in fear of massive propwalk. She overcame what there was in short order. That said, in tight waters such as a narrow marina corridor and an awkward berth, I’d have wanted a bow thruster to control so hefty a boat in any weight of wind.

Across the wind with the prop working to pull the stern into line as the bow blew away, the Bénéteau put in an exemplary demonstration.

Conclusion

Without doubt, the secret of controlling a boat astern under power is to know her habits, to consider how these will be affected by conditions, then set up any manoeuvre to give her the best chance. If our knowledge of her suggests she’s going to sulk instead of doing what we want, we must either think again and find a different way, or at least have the crew standing by with fenders at any likely crunch points. Working in harmony with their natural tendencies, most yachts will do what they’re told in the end, given enough space and a determined hand on the helm, but there are one or two that just won’t come into line. They are often found among the classic passage makers of our day; to balance the equation, it must be said that some modern yachts that steer perfectly astern are skittish in a seaway. As Mr Bugatti might have observed had he been a yachtsman, it pays to remember what the boat is really for.

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