From the Drawing Board
Occasional ramblings from
a Small Craft Designer

by John Welsford


We tend to take it for granted that any boat we pile into will handle and react in much the same way. Cars do by and large, and perhaps this is a good thing as it makes them pretty predictable for the 99% of drivers who have not the experience or skill to make use of something with a bit more character. And perhaps even more of a good thing for those who think that they have but who aren't if you know what I mean!

But boats, sailing boats that is, (the other kinds are after all just badly shaped sailing boats that someone has forgotten to put sails on) do differ. Many boats, the ones with rigs that have triangular sails, no bowsprits, short fin keels or centreboards and spade rudders do handle much of a muchness. They are relatively easy to handle, are not very sensitive to sail trim, and the powerful rudder is able to correct any imbalance caused by poor weight distribution or bad sail trim.

In the past, the days of the old cutters and gaff sloops the boats were descended from working craft and had deep full length keels and a deep forefoot that was immersed almost to the maximum draft of the vessel ("It gets a goodly grip o the watter, aaarrrrrgh" ( hoik spit ).

The rig was correspondingly long, a forty footer might have 12 foot of bowsprit, ( known as "the Widow maker aaaarrrrgh hoik spit) and a boom that would have required a tree the likes of which would have enough timber in it to build the whole of today's style of forty footer ( "Moind yer 'ead boy, take it roit off hahaaaaargh" ( Hoik spit).

The resulting craft would, even at its best, not take too much notice of the man at the tiller, and it took considerable skill to control the beast. But this was normal and the boats direction was controlled as much or more by sail trim ("easum the mainsheet lad, we'm need to bear awa hahaaaaargh!" (You got it, chewing tobacco was pretty common in those days)) as it was by the rudder.
Boats that had so much directional stability that they were able to be left to their own devices for minutes at time were prized among the working craft from which our recreation vessels originally sprang, and it was accepted that some skill in trimming sails was part and parcel of the helm position.

Today? We don’t have the old country accent and try to keep our teeth rather whiter than the plug tobacco would allow, and we no longer have boats which need that same depth of experience and skill to make some progress in the right direction.

Yes, there is skill, but today’s boats need skill to get the last 10%. While I know of a young man who, out sailing on a vintage Bristol Channel Pilot cutter, yawl rigged oddly enough but still a Pilot Cutter was handed the tiller and told to keep her "full and by". He stood his watch keenly watching the sails and noting the direction of the wind while the massive old 50 plus footer charged along, making tiny adjustments to the helm and concentrating fiercely. He was hugely taken aback when the skipper came up to relieve him. Instead of taking the tiller in his hand and casting a keen eye up at the rig, the old man just looked about, noted the course and time on the day log , eased the mizzen slightly to let her sail a little freer and sat on the cabin top letting the boat sail herself.

He was not just taken aback but seriously discomfited to find that as she had been sailing no amount of helm would have made her deviate more than a couple of points without sail trim changes, and that he'd been given the helm knowing full well that he could "do no 'arm" and to keep him and his constant eager busyness out of the skippers hair!

Todays boat though are different. We expect the performance of the highly tuned light displacement yachts, even from those boats rigged in the old style with gaff and bowsprit. But a boat so designed and rigged is going to need different skills, a little like driving an English sports car after your Chevy or Toyota. You need to be in tune with the rig, feel it through the tiller and sheets, and instead of just hauling the tiller over when she wants to do something else, change the sails to suit the new course and you will find that she will want to follow your lead.

I had a couple of early enquiries from people who had built Penguins, centreboard shoal draft cabin yachts with a lower and longer rig than is common today. They were puzzled to find that sometimes they had heavy weather helm, and sometimes slight lee helm. this was quite outside their experience and so, having gone through a similar learning curve years before on a V class ( 18 ft hard chine gaff rigged centreboarder of extreme beam) I was able to advise them of the advantages of a boat that could be trimmed to actually help the helmsman rather than fighting all the way. Below is my essay on sail trim and its effect upon the steering of a gaff rigged centreboard cruiser.

Tuning a centreboard gaff sloop.

Notes on sailing Penguin.

Below are some ideas on tuning Penguin, some credit to Geoff Beale who has one of the very first ones to be launched.

In sailing a gaff rigged boat, especially a centreboard one with its short lateral plane it is necessary to remember that the long base of the rig can be both an advantage and a disadvantage. As the rig has a comparatively long base very small alterations can produce quite noticeable changes in the way the boat steers, and understanding those changes can make a gaffer a real pleasure to play with.

A gaff main has much more adjustability than a marconi, or jib headed main which enables an experienced user to do things which seem impossible to the "modern" sailor but it does take patience to understand that balance. All of this would be second nature to an old working boat sailor from the inshore fisheries, but the rig is so very different to the boats in which we learn to sail today that those skills are sadly almost lost.

Because the boat reacts to relatively small changes in sail setting it is possible to use that to get the boat sailing well and balanced in a wide range of conditions, or otherwise make hard work of it if not sailed appropriately.
In this case we have two separate problems to address, the first being the weather helm when the wind gets up. Penguin is designed with an optimum full sail wind speed of 12/14 knots, 20 knots generates over twice the heeling force that 12 knots does so the sail trim that produces a nice amount of pull on the tiller at 12 knots, will have the boat heeled so far that her designed in safety measure of rounding up when heeled too far will overcome the rudders correcting force.

Reef early, this is a big rig for a small boat. As well as allowing the boat to stand up like she should, reefing the main moves the centre of effort forward to counteract the boats weather helm. As the boats speed through the water increases you need less lateral plane so pull the centreboard half up, as the 'board moves aft through an arc the first half of the movement moves it aft more than up, moving the centre of lateral plane aft giving the same effect. Ease the mainsheet enough to twist the top of the mainsail off which reduces the heeling moment allowing the boat to sail on her feet, boats like this are not intended to be sailed like the old deep keelers, over on their ear, but need to be kept fairly upright or they develop excess weather helm.

As the mainsheet is eased you need also to ease the jib a fraction to keep the slot between jib leach and main open so the airflow is maintained, if this is not done then the boat will heel rather than go forward, and will develop, you've got it, excess weather helm!

You can, if the boat is fitted with jib sheet tracks, move the sheeting point aft and outward which also helps.
If you have lee helm when sailing under genoa, check that the sail is sheeted far enough aft, the top third should luff before the rest of the genoa, and you should be careful not to let the main twist or the jib overlap will close the "slot" and the big jib will blow her bow off . This sail is very sensitive to setting and should be sheeted from as wide out on the side deck as you can mount the sheet block. When tacking with a sail as long on the foot as this is, let the sheet fly the instant you are ready to put the helm down and sail her through on the main before letting the wind bring the genoa through and then sheeting it home on the other tack. In very light weather and sloppy seas it might even be necessary to bear away slightly and build speed before putting her about.

Check that you have not accumulated too much weight in the cockpit, and if necessary stow some of your heavy items in the space under the after end of the forward bunk to get her trim right, if stern down she will not go about as the Centre of Lateral Resistance is then too far aft, although roomy she is still a small boat and sensitive to fore and aft weight distribution.

In light weather it helps to have the main sheeted fairly hard in to keep the gaff as close to the centre of the boat as possible, a good indication is that the sail batten second from the top should be parallel to the boats centreline, while at 15 knots of wind it should be pointing almost as low as the stern quarter and the jib sheeted correspondingly "low". This has a profound effect on the feel of the boat, and her ability to drive forward rather than heel over and round up.

There are many more subtleties to the gaff rig, for example the relationship between the tensions of the throat halyard, the peak halyard and the gaff outhaul which can substantially alter the fullness of the mainsail in the top third of its hoist thus giving the boat more or less weather helm. The relationship between the gaff, the boats centreline and the twist in the jib, and so on. One of the things I enjoy about the rig is its immense adjustability but I must admit that I have spent quite a while reading John Leathers "Gaff Rig" among other books and have done a fair few miles under the old fashioned sail.

John Welsford