Strong wind downwind in unstayed Cat Ketches and Cat Yawls – more safety and efficiency


In the recent Texas 200 event – 200 miles up the Texas Coast in small sailing boats, the general consensus was that the Goat Island Skiff was one of the faster boats.

Goat island skiff sailing in the Texas 200.

More info about the Goat Island Skiff Plans

I was only able to make the trip because of Chuck and Sandra from Duckworks putting me up and John Goodman, the owner/builder of the Green Goat Island Skiff “GIR”.  It was a particular pleasure to sail with John (left in pic below) because he is a very good sailor and was interested to make as much from the learning curve the conditions provided as I was.

Australian Goat Island Skiff - built in Texas

Though one of the smaller boats in the fleet it was able to perform equal or faster than much larger boats.  Part of it is the boat is lighter and simpler than most of the other boats with good reputation for speed.  The other thing was we were doing something in a very different way to all the other boats.

The winds were strong (25mph – 20knots plus) and from the stern.  It meant lots of high speed running and broad reaching.  Points of sail where control can be difficult as the boats roll around badly as they encounter large waves.

Goosewinging – sailing fast by the lee in unstayed sailboats

Most sailors have some idea of goosewinging.  Particularly as many boats move to much cheaper and easier to handle unstayed rigs – most will goosewing when the wind is from behind.  Most do it the wrong way.

Normally the crew will flip the mizzen over to the opposite side.  This is the wrong thing to do for best performance and in many conditions for safety.

A better choice is to allow the mizzen to flip over to the side it wants and forcefully gybe the mainsail to the other side.

The following diagram explains why in most conditions it is better to gybe over the mainsail.

Cat ketch and cat yawl sailboats - fast sailing - performance tips

In the left image the mizzen is partially blocking the wind from the mainsail.

In the right the mainsail is completely exposed to fast moving fresh air.  Or, even better, it can be in the stream of accelerated air that passes either side of the blockage caused by the mizzen.  Racing sailors will know a similar effect when you go either side of an island or there is a big bunch of boats just to one side of direct upwind.

So that is for speed.  But the important thing I want to show is also how it is good for SECURITY and makes sailing faster.

Control of heel and powering up through sailing by the lee

Because almost all the sailing in the Texas 200 is with strong winds from behind we had hours each day to play with different settings. For years I have used Sailing By The Lee to maximise speed.  But I had heard A second advantage of sailing by the lee has two stages of explanation.  This part also applies to cat rigs that are unstayed.

fast downwind sailing - controlling heel with mainsail by the lee.

The diagram above shows what happens to the heel vector as the mainsail is trimmed in and out.  The boat will heel one way when you pull the mainsheet in and the other when you ease it out.

We used this actively when sailing the Goat to give the boat the angle we wanted.  If the boat starts heeling in the wrong way or becomes unstable this method gives you a powerful method to bring the boat upright.

We even took a video – it shows how powerful this method is for controlling the heel – the response of the boat is instant and powerful.  We didn’t have to worry about the boat rolling or heeling uncontrollably in the fast running and broad reaching conditions.  In the video I get the windward and leeward side mixed up – very easy to do when sailing by the lee – and it shows how new to using the method we were.

The reason this is such a powerful method is that at all times the mainsail has full power.  The following diagram shows why.

Sailing fast by the lee and controlling heel

In the left diagram with the mainsail on the conventional side you can also control the heel by sheeting the mainsail in and out.  However there is a limit because the sail loses its power as it is eased – it starts to luff.  This can mean that just when you need the power to pull the boat upright you lose the power to do so.

When by the lee the (boat on the right) power increases dramatically as you trim in the mainsail and the sail moves from stalled to having smooth flow from leech to luff reversing the normal flow direction.

From a speed perspective it means that not only do you have control to avoid a nasty roll in the wrong direction, simply by pulling in or easing the sheet suddenly a few feet, but whichever way you are forcing the boat to go the mainsail is developing full power the whole time.

Limitations of sailing by the lee

During the Texas 200 we started off with a fairly gung ho attitude.  “full mainsail or one reef” and then towards the end we were usually deciding between second and third reef.  Part of the reason was that so much power was available using this method that we were able to keep our normal sailing speed above 8 mph at any time and most of the time around 10 mph (just under 9 knots) with sprints up to 12 or 14 mph.

Sailing fast by the lee

Very good speed for a little boat – and it was consistent speed – not momentary.  The only boats the little Goat Island Skiff was unable to overhaul were the catamarans in the event.

The downside of the by the lee method is as the wind increases there comes a point where the boat is going so fast in the waves that it overtakes a wave at such speed that it digs its nose into the wave in front deeply.  Happily with the balanced volumes of the Goat hull this does not produce any veering or helm loads – quite unlike 1980s style planing boats that have wide transoms.

At the point this is happening consistently we simply stopped, sheeted in the mizzen to hold the boat on a close hauled course and put another reef in the mainsail.

If we were not sure that another reef was the best choice we would gybe the mainsail so the more usual position on the leeward side and accept that the sail would lose power when eased – something we counted on.

Goat Island skiff at the end of the Texas 200 sailing event.


 


4 thoughts on “Strong wind downwind in unstayed Cat Ketches and Cat Yawls – more safety and efficiency

  1. David Kirtley says:

    Hey MIK, good to see you survived our lovely heat.

    I am really curious how your opinion has changed or remained the same regarding the yawl rig (or the cat ketch by extension) in comparison to a single sail.

    I do know that on the old sharpies, they would let the sail fly forward of them mast when running just to stabilize. Did you try that?

    In a more specific vein, now that you have spent some serious time in the sailing conditions we have down here, what do you think would be a good choice for a generally comfortable sailing boat for single handing these conditions? Keep in mind that the wind you experienced was not exceptional in this area. You should see it when it really gets blowing.

    • Hi David,
      The single sail is by far the best solution for off the beach sailing – you can rig in minutes and get going. The boat is less cluttered, significantly cheaper and less labour.

      However for a distance event or cruising having the ability to hold the nose to wind or the boat abeam of the wind does allow reefing much more easily. In the Texas 200 it would be mostly possible to pull ashore to reef if the wind had come up – but this would require a degree of thought and calculation and probably conservatism before crossing some of the larger bodies of water – like Matogorda Bay etc.

      All in all I was very happy to be sailing the yawl version for this event.

      Best wishes
      Michael

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