hi all,im reading alot about gybing centerboards and on the face of it they look like a good idea.Has anyone used one and what was the differences between it and a standard board?
Also does anybody have a contact number/email address for Jon Turner?

Been tried many times over the years. Most people don't use them.

Still used in other classes (Int 14?) I believe, but not in Merlins.

If you are enjoying the research, don't forget to find out about asymmetrically-shaped gybing boards!

Have a look at http://www.int505.org/eck1.pdf and http://www.int505.org/eck2.pdf

I used a gybing board on a 12 successfully (I think!)  The difficulty with gybing boards is they tend to be a sloppy fit in the cb box until they are loaded up.  Best results are achieved if you foot the boat rather than pinch, which tends to suit heavier crews in more powerful boats, probably best on big sea courses and not so good on the river or Salcombe.

Alan warren used to use them and i think (Barry dunning may correct me, long before my time!) and they broke. a lot!

Guy Winder had one in stiletto on a cam. He found as he reduced the size of the cam the boat went better so put a standard board in! This is mentioned in his article in the library

They did tend to break but then they were made of timber. With modern materials they would be a lot stronger. The biggest problem was the extra water carried because the slot had to be that much wider. Absolutely right about footing off. We were sailing with 22 stone so not to heavy. A heavier crew would have benifited much more. Also you had to make sure that the plate had gybed on the pin after every tack. Great in a breeze, but didnt seem to work in lighter conditions. Then neither did we!

The thing to remember about gybing boards is that they don't work they way you'd think they do. The reason for that is that your boat sails according to the angle between plate and sails, not hull and sails. So if you have a board that's angled 5 degrees you're effectively sailing with the hull rotated with the bow 5 degrees to leeward... That is why people figured they had to foot off. Actually they were sailing with the foil at the same angle to the water and wind...

surely if you can ease your sheets you will be developing more power hence more speed.If the board is keeping your point and you are generating more power from your sails then gybing boards should be quicker.I know all the current generation of 5o5's use them.

Interesting this thread; in my day I think we were very much more secretive about things, such as our ballasted boards -(No max centreboard weight and weight included in the hull.)- and gybing boards, Robin Judah certainly had one in his boats, I adopted one in 1964 with a stunning improvement in pace, (Maybe I was growing up and getting better anyway.) I had one in my subsequent two boats - the same board actually -, we never lacked pace to windward and it was good to be able to free off to pass a boat to leeward in a one sided beat (Which we seemed to have a lot of in those days.) and at the same time lift up under them! Never experienced (Knowingly any way.) Barry and Alan's point about not moving on the pin; but I was lucky to have a crew in 1964 who was a fellow at Imperial College who got the board made in the workshops with all sorts of reinforcing materials (It was very stiff ans strong.) and a PTFE surface to the bit that stayed in the case. Just raising the board a smidge stopped it gybing in the case,so it was easy to switch off; the 505 point is well made I think most leading 505's had gybing (Rocking.) boards after the Farrant brothers from Hastings dominated the class with one in the late 50's and 60's. So if you can make your own or can afford a custom made one (Try Milanes Foils.)I would say it's worth a go and make your mind up after trying it, you do not need a wider case slot just a diamond top shape (widest bit at the rear.) and of course the symetrical air-foil in the water.

I wonder if the reason it doesn't work so well in Merlins according to the Stiletto experiment is to do with leeway.  Once powered up a Merlin makes very little leeway, does a 5o5 make more?  Another thing to fiddle with - doubtless someone will invent a device to alter the angle of the foil in the case whilst sitting out hard and playing the board up and down and the rake of the mast and the kicker and the lowers and the...

Cliff Norbury had such a device on his last National 12, however I suspect he was by then a bit heavy for a National 12, though I THINK he won the Burton Trophy with it.

Good article on gybing boards on Hornet site.


http://www.hornet.org.uk/forms/20051113104700centreboards.pdf

.

Come on Deepy, you got to have some views on this topic.... ;-))