Gybing Plates

Originally posted by gordon1277 Hi GRF Have a look at a free download called Trueview which allows you to view and plot CAD files. Gordon What a shame about all the boats lost at Cowes some peoples years of effort in restoration just gone plus classics we will never see again. Awful for all concerned.

Thanks, and I know what you're thinking, it wasn't me, I've got an alibi!..

That guy if you'll pardon my impatience is talking bollox. So much crap in what he was saying then, typical example of a good sailor having an opinion, juxtapositioning facts to support it and I can't be asked to pull it all apart, but he's wrong. Allthough I'm grateful nonetheless for you posting me a link I will have to come back to it later some of those equations annoyed me..

Carrying 2 kgs of water around in the centreboard case, yeah right... Whatever water is there, is there regardless and any more or less is a result of the efficiency or inefficiency of flushing strips, now attention does have to be paid to them if you are going to use gybing plates, but it's not beyond the wit of man to overcome.

Edited by iGRF - 26 Jan 16 at 7:54pm

Yep even we used to try that in light weather with a foam block but it really doesn't make much difference unless of course your flushing strips are not cutting it as they should, which at championship level you really couldn't afford to happen, back in the day some of us would have a fresh set every major event.

The key thing about water in the centreboard case, isn't wether it's there or not, it's how badly it's moving about.

Edited by iGRF - 26 Jan 16 at 7:38pm

Originally posted by iGRF That guy if you'll pardon my impatience is talking bollox.

I think he's more wrong than right though. It is striking that all the classes I know of where they seem to have gained a significant measure of popularity are two sail classes. I see two possible factors. They're all about the fact that what gybing boards do is in effect rotate the hull round the foil.

So the first effect is that if you get the gybe angle right then the hull centreline is aligned with the direction of travel, not crabbing by two degrees or whatever. I used to think that was probably insignificant, but I've seen some calculations by someone I respect which suggests it isn't.

The second effect is that the alignment of jib and mast changes (if you have a jib). The 505 guy goes into great flights of enthusiasm, in which I think he's forgotten that sailors sheet their sails relative to the apparent wind, not the hull, but nevertheless there is a change in an area where I find tiny changes matter.

As for the weight thing, well, yes, if your gybing board arrangement means you have a fatter case than someone without one, then that is a little more weight. Not convinced about the significance though.

Edited by JimC - 27 Jan 16 at 11:36am

I did look at this for my Sprint, the main issue I looked at which suggested not doing this, was the slot is only about 5" deep, the pressure on such a short section of centreboard could be catastrophic, you are in effect loading up a reduced surface area, when you shave off material.