On sailing a Folksong – rudder 4

Further to my previous posts, here, here and here, the following is taken from “Singlehanded Sailing”, by Richard Henderson.

He is talking about the Folkboat – (the Folksong is a Folkboat derivative):

“She (the Folkboat) has considerable aft rake to her rudder, which results in less lateral plane and less wetted surface. There was a time when some sailors thought this feature was detrimental to self-steering, but this thinking is not so much in evidence today.

. . . a considerable rake aft often causes the rudder to operate more efficiently when the boat is heeled or rolling, at which time the resultant of force components working on the rudder is acting in a more lateral and thus more effective direction. It is also true that gravity tends to keep such a rudder amidships when the boat is unheeled*. The really important concern with regard to self-steering is the directional stability of the hull, which is generally achieved through a reasonably symmetrical shape with somewhat balanced ends and an ample, but not necessarily extreme, length of keel.”

* And presumably the heavier rudder will be more effective in maintaining this.

On Blue Mistress, I am able to leave the tiller and go forward to adjust lines at the mast – (usually to loosen the lazy jacks which interfere with the mainsail shape if left too tight). She holds her course for the time it takes.

On sailing a Folksong – rudders 3

I have been gathering information on rudders – see my posts here and here.

The following by J.D.Sleightholme in his ABC for Yachtsmen, is useful.

Published in 1965, original price 21 shillings, and bought in one of my favourite secondhand bookshops –  Books by the Sea, Bude, Cornwall.

The question is what effect Blue Mistress’ rather heavily-built rudder have on her performance?

It’s one of those subjects that has several different answers depending on who you talk to. At the moment I’m gathering information and listening.

Blue Mistress’ heavily-built rudder.

Mr Sleightholme writes:

“A yacht should handle with the minimum use of the rudder (which slows her).

Deep narrow rudders are more effective than wide ones and have less slowing effect. As a rule, deep rudders are broader at the top due to difference in water density.

A steeply raked rudder exerts additional force in pulling the stern down when hard over.

In tacking with good way on, very little rudder is used at first, but more is applied as the speed drops – (never more than 30 degrees). Jamming it hard over may mean missing stays.

Power craft have proportionately smaller rudders because they work in the slipstream of the propeller. May be “balanced” with a small area forward of the rudder post.

Sailing craft may have 12 – 15 per cent of immersed lateral hull area in the rudder, power craft about 5 per cent.” (p.100)

This says more about shape and angles and less about weight, but it takes us in the right direction.

On sailing a Folksong – rudder 2

Blue Mistress has a very heavy rudder – “overworked”, the marine surveyor called it.

It might have graced the stern of an early twentieth century vessel.

Compared to similar sized craft, it is also slightly short of the keel . . .

For example, another Folksong 26 . . .

a Folkboat . . .

a Contessa 26**  . . .

This may mean that Blue Mistress’ rudder has been repaired sometime in the past, but it may not . . .

So, I’m looking for the answers to three questions:

What is the effect of a heavy rudder on the sailing performance of a long-keeled boat?

What is the effect of a shorter rudder on the sailing performance of a long-keeled boat?

What is the effect of rudder shape on the sailing performance of a long-keeled boat?

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A younger me would have searched for a definitive answer.

Now I don’t think there is one answer – but a series of ideas about rudders that, put together, mean we can learn more about small, long-keeled boats.

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For example, a Google search showed the Swedish Folkboat Association having a useful note on this – here.

In their submission to the Nordic International Folkboat Association, they state: “We have consulted Lars Larsson, professor in hydrodynamics on Chalmers (Gothenburg’s technical university), folkboat sailor, and earlier three times Swedish Champion in Folkboats. He thinks that the lifting power 10 kg has a moderate effect – the same as if the whole crew (250 kg) moves 0.1 m forwards in the boat. Hydrodynamically it can be a favour to make the rudder a little thicker, so that the water follows a harmonic bend along the keel and rudder on the boats windward side when it tacks with a rudder angel of about 5 degrees ( to prevent the boat from turning up against the wind). The shape of the leeward side is of less importance. To make an even thicker rudder is a disadvantage hydrodynamically.”

The Association then dealt with it in a formal fashion, i.e. there is a revised class rule to be adhered to – here.

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Fair enough. But here are no class rules with a Folksong 26, so we have some leeway, which means we can work it out for ourselves . . . with a little help from friends.

If you have answers, part answers – or even more questions, please feel free to comment..

**(I am very grateful to Nick for allowing me to use this picture of Constellation. I enjoy his blog and highly recommend following and supporting his venture back to Australia on Big Oceans/Tiny Boat)

On sailing a Folksong – rudder 1

Getting to know a boat . . .

How long does it take to get to know a boat?

Longer than most people think.

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When I first sailed Blue Mistress, she had a lot of weather helm.

I thought it might be something to do with the rudder.

It became a feature of our sailing – slowed us a little but it didn’t stop us. I got used to it.

Then I discovered it wasn’t necessarily the rudder.

I learnt to trim the sails more carefully, and got used to selecting the ‘right’ foresail for the particular weather. I reduced it – significantly.

That was a pretty obvious, you say.

Perhaps, but, problems often work that way – they crop up and are set aside to be solved later. We get used to them and move on because there are plenty of other problems to deal with.

The bigger, more pressing problems draw our attention and the lesser ones are tolerated and fade into the background.

As a result many of us live our lives at less than our full potential – mildly (or heavily) inhibited by a pot full of unfinished business.

“All problems carry their own solutions” (anon), but it takes some event to stir us into revisiting a tolerated problem and looking for the solution.

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So with the weather helm.

A calm day, force 1, following two slightly bigger yachts with different keels, wondering whether I could keep up – (it was already apparent that my leeway was less).

I was sailing with the No 1 foresail. The lighter, larger genoa would have made a lot of difference.

On Blue Mistress, the No 1 foresail works best in a blow with one reef in the main. It was good practice to be working with it in light airs.

Easing the foresheet to give the foresail more power, and bringing the main sheet up the traveller and the boom midships, took some weigh off the tiller and gave us an extra half knot in the light wind.

They always had the edge on me in this light air, but we sailed all the way to Cawsand whereas they tacked back as they approached Picklecombe Point.

Straightfoward stuff.

I didn’t solve the weather helm problem, but I did consider it more closely and began to tackle it.

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And I enjoyed the sense of a race.

Sailing is always a race – sometimes against other boats but mostly against the tide, the weather, time – and our own need to keep up.