I've just read this article:
http://www.fastcomposites.ca/publications/PhantomCentreboard.pdf

I'd like to get in touch with the author but can't find any contact details.

I understand his name is Andy Hay and he now sails a Merlin.

Can anyone help?

Thanks
Stu

Guilty as charged M'laud. Board was fast, if I could keep the boat upright. Weighed less than 1kg finished. Merlin centreboard to come ... (maybe attached to a new boat, but that is a different story)

Seriously Stu, I'll email you off forum when I have a working email system (server has died). Maybe later this week or early next. Of course, quite willing to give info into the august Merlin Forum.

Andy

Come on - we'd all like to hear about it!

Although dont' some MRs prefer a heavier board to get a hull up to weight?

I would certainly like to hear about it! Many older boats suffer from being too heavy and a way to reduce weight would be very interesting. It would also be a good winter project. I recently built a rudder blade using the techniques shown on the Cherub website - very satisfying! My only concern about centre boards is that I understand the correct degree of flex is important and that could be difficult for a mere mortal like me to get right. I await further details eagerly!

Been to the Phils Foils website and looked at the detail. If as the pictures are a fair description of the quality, worth a look. Be interested to know how the costs compared to the Uk and how much TAX!

You probably will have to pay VAT @ 15% if the value exceeds the minimum - currently £18 (so yes) but it appears the duty rate could be 0% (no duty anyway on goods below £105) see link......

Andy,

I don't suppose you have any pictures of the rig set up on a Phantom do you? 

I have just bought one to restore and it is in a bit of a state with a very messy and out of date rig.

Any advice would be great.

P.S. This is not to replace the Merlin, just a toy for the odd weekend when the wife does not fancy sailing!

Merlin advice only on the forum please - if you want to talk about Phantom rigs, my knowledge is a bit out of date - I last sailed one with a tin rig (best was Wavelength). I did write a tuning guide for the rig that I used, was quite quick for a season, winning all but one Open and third at the Nationals. Talk to the class association or to Graham Scott at Wavelength (google Wavelength Designs).

Yes, the foil was made by Phils Foils in Canada, he might have forgiven me for the shape of the blade head. Try an ensure that all transit papers are marked with "sample" .... sorry if anyone from Customs is reading this. The cost at the time was very good, not sure about the exchange rate. PVC foam core with a carbon sheath, weighed about 1kg finished. No-one in the UK could approach the cost that Phil was charging, even including shipping. Since the method that Phil used (at the time) was to CNC cut each half of the board individually, this did give a slight twist to the trailing edge. I wasn't satisfied and was provided with a free replacement. Cannot recommend the service and quality highly enough.

Keels on yachts are heavy, so traditionally centreboards are also heavy. The MR Rules have a maximum weight of 8kg and most will be about 4 to 5kg, so get a 1kg foil made and add 3kg of lead. The Phantom Rules (at the time, cannot comment now) had a rule that the board must float. I always remember a conversation with a Lark sailor in heavy winds saying that the boat was tripping over the board as their metal (i.e. very heavy) centreboard was not allowing the boat to lift over its bow wave. Personally I prefer to have lead in the boat.

With regards to flex, this is dependent on your rig. Basically, if you have a stiff mast, have a flexible board, and vice versa. Laminar sections are the way forward, but must be honded, polished and maintained.

Barnsie - can I contact you off forum to discuss a bit of interesting Merlin project that I am contemplating that might be right up your street?

Conventional wisdom suggests that you want the weight as low as possible. Thats why the corrector positions are restricted.

The lark issue isn't, in my opinion, about weight of the c/board, but total weight, lighter boats get onto the plane faster.

With most Merlins in th elast 15 years carrying at least 6 kilos of lead, saving a couple more out of the c/board isn't likely to be  a priority.

Shape, stiffness, fairness etc would be a more importnat factors

In fact where you want the weight is as close as possible to the centre of rotation of the hull to minimise the pitching moment and this will be around the waterline, it's not going to be an issue with righting moment until the boat has heeled beyond no return.  Taking weight out of the centreboard may not make a great deal of difference if it is just the 3-4 kg we are talking about.  I always hope my centreboards are strong enough to have my flailing body slip over and slide towards the toe in a capsize.

Of course you could have a light weight board, with a lead tip. I guess that's why the Phantoms had the must float Rule. Again, personally, I would prefer to have the weight fixed as correctors than have 7kgs swinging around at the bottom of the board. But each to their own!

For those without a modern boat with lots of lead, a lighter weight board would allow some to keep pace when the weight reduction comes (which I think it will at some point, but this has been discussed at length on other threads). Our boat is 20 years old, still has 4kg of lead and a heavy (4kg ish) board. So we could probably withstand a 7kg weight reduction, with careful paring, looking at the fittings, etc, we might get this to 10kgs. Some others might also be so lucky.

I would concur with Alan, that shape and finish are more important if you are not worried about weight.

As a boat starts planing the boat rotates about the centre of pressure, which is surprising aft. Hence the centreboard will be in front of this at speed. Maybe we should change the Rules to allow the lead at the transom!! I recall that Dick Batt put a very heavy compass on the transom of Dangerbatt when she was new.

The first Merlins in the 40s had lead tips on the centreboards - was that to help the heeling issue, or more becuase their cases were constructed to let the board slide back, not pivot?!

Probably both, understanding in the 40's, well before my time, probably suggested that weight low on the board, like a yacht's keel is a good thing. I also think that the roller arrangement needed a little weight to get the board to slide down and stay down, otherwise it will have floated back up again.

It did occur to me on the train, the same thought as Andy, that if there was an easy and cheap way to get weight off older boats this would remove some concerns over weight reductions.

As far as fore-aft weight is concerned, ideally you want it at the 'ends' rather than the middle, as far as I understand, to reduce pitching in chop. Also we all know that too much in the tramsom is bad due to drag.

It did occur to me on the train, the same thought as Andy, that if there was an easy and cheap way to get weight off older boats this would remove some concerns over weight reductions.

As far as fore-aft weight is concerned, ideally you want it at the 'ends' rather than the middle, as far as I understand, to reduce pitching in chop. Also we all know that too much in the tramsom is bad due to drag.

Ah, there is the apparent contradiction. You should get the weight out of the ends as this is the best thing to reduce pitching moment in a chop, when the rig is oscillated fore and aft, and when going into waves. But actually you are looking for a reduction in the radius of gyration (good word that!), which is the lever of all parts of the boat from the centre of rotation. This will include the board and the rig of course. Taking the weight to the ends of the boat will damp the pitching motion, as the radius of gyration will be increased. This will have the effect of the boat ploughing through, rather than lifting over the waves.

However, thinking about the motion of a planing dinghy downwind, you want the weight out of the bow (to reduce the lift required, which reduces drag) and out of the middle of the boat. This is why we move crew weight aft. The centreboard is frequently out of the water, so this is well in front of the bow wave.

Actually, I think that it is not weight at the back that is slow, it is stern down trim. Get the crew weight right so that the water flows horizontally off the bottom of the transom, rather than bubbling round.

So correctors on tracks along the hog? We've got everything else adjustable .....

Carbon light weight board was about £250 shipped, but I finished that myself, although that was some years ago. But yes, this is the way that we can minimise the impact of a weight reduction for heavier boats. The head of the new board can be matched to the existing board, so that this will not affect the case or pivot position. Perhaps everyone taking lead out, can pool the scrap value and help to offset the costs for the older boats .....

Correctors must be in a fixed position above the water line, no tracks allowed. Centre boards pivot bolt on the other hand can be on a track (parallel to water line), hence one of the reasons why the weight of the board is capped, to prevent the option of moveable ballast.

Plenty of moveable ballast a merlin, normally 20-25 stone of it :-)

Alex, correctors can be fitted anywhere in the boat, just need to be permenently and rigidly attached (Rule 5c) - see the 2009 yearbook. If you are going to change this to above the waterline, then most new Winders will not comply (especially Tom's boat at Sailboat). As it happens our old girl has the correctors under the case capping so they are above the waterline.

Rule 5c does not make it clear that the correctors cannot be moved, just need to be permenently and rigidly attached (but does not say to what). So you could interpret the Rule to allow a corrector permenently and rigidly attached to a traveller car, which can whizz up and down a track, also permenently and rigidly attached to the hull.

For the record, I do not want to do this, but the possiblity is there. This is more of a can of worms than the whole T foil debate!!!!

10 kgs of lead is small fry to our 150 kg of crew lard, so all a bit pointless really!

in the vast scale of things is spending £2.50 per 10 grams of weight saved really worth the expense?

Most of the weight in the board is in the middle anyway and is of little relevance to the pitching motion of 98kg of boat plus 10 to 15 kg of rig which is much higher.

Oh no, don't start all this again. Do people really needs to see the results of the swing tests again?

Stick correctors in the middle, and the rare times you find yourself needing to reduce pitching (no wind, lots chop) move helm and crew as far apart as possible (see Bethwaite's book).

The rule is clear

The corrector has to be added to the hull - permanently - not a traveller and be above the approximate waterline

5 c 
A corrector is a piece of any material added to the hull for the purpose
of adjusting the total weight to comply with class rule 5(b). Correctors,
if required, shall be located above the approximate waterline and be
permanently and rigidly attached by screws, bolts or adhesive.

The 2009 & 2008 yearbooks do not mention the waterline in Rule 5c - unless I need new specs. And yes, I agree that this is not worth the hassle and has rather taken the thread off topic!

Yes it is a bit annoying that RYA still only has 2003 rules edition

But hey the Merlin Rocket is not a Manufacturers One Design or going to provide Gold Medal Publicity, they don't care!

I think the waterline rule was removed as it was difficult to judge where it was and made no differance anyway whether the weight was above it or below it.

And presumably because it could mean that you were out of class shortly after a capsize?!