BR20 downwind performance

[Graham W]

Here's a great photo taken by Osbert Lancaster http://forthsailoar.osbert.org/ of the sailing race on Loch Oich during Sail Caledonia 2012.  It was taken from the 100 year old Orkney Yole 'Mohican' and shows our BR20 'Turaco' side by side with the Caledonian Yawl 'Elsie', the eventual overall winner of the series.

Although we were mostly faster upwind, Elsie usually left us for dead downwind. She is more or less the same length as us and at 16m2 has 1m2 less sail, split between a balanced lugsail and mizzen (no foresail).  So as can be seen from the picture, we may have had our jib up but it wasn't doing much, whereas both of Elsie's sails were working hard to gain an edge on us.

Any suggestions to improve the BR's downwind performance?

[Peter Cockerton]

Graham

The smaller area of wetted hull area is probably helping on Elsie resulting in less drag don't you think, also the main looks to be looser on the foot creating a fuller sale on the main, not sure on the mizzen as it is not as clear on the photograph.
What do you think.

Peter

[Graham W]

I think you may be on to something on both counts.  Attached an enlargement of the original photo, which may or may not help with clarity.

The BR looks, and is, beamier (2.05 vs 1.88m) and Elsie is also double ended, so the drag should be less?

On the sail side, both their main and mizzen (but especially the main) are looser footed than ours, which we could have done something about if we had thought about it.  I think their mast is unstayed, which is why only our main is distorted by a shroud.  Plus our mizzen is tiny compared to theirs. Which brings to mind the other thread about whether mizzens are useful or not.  What if the BR mizzen was larger?  Would better downwind performance be at the expense of greater and possibly unsettling weather helm upwind?

[Tony]

Hi, Graham.

Here's an opinion for you.
The Caledonian Yawl, being a double ender, ‘ puts the water back together’  so less energy wasted making a wake at low speeds. She won’t plane like the BR20, though,  when the wind gets up. The main difference between the boats  in the conditions shown is the choice of sail.
The BR 20 is much more efficient into the wind with that higher aspect ratio set-up  - but always put your money on a lugger going down wind! 
On a dead run the lugger can slacken off the luff downhaul and allow the boom to cross the mast even further than normal. You then effectively have a square rig with much more of the sail doing useful work than a Bermudian  can manage. Additionally, if you are on whichever tack has the boom in front of the mast, it can move forward and upward a little. The sail shape produced will actually lift the bows quite markedly in stronger gusts rather than press the bows down as you get with a Bermudian - especially one with a fine entry like the Bay Raider. (Ever noticed how traditional fishing luggers , Herring Busses and even Nelson’s “Victory “ look decidedly chubby in the bows?)
If you want to go fast down wind in a BR20 use a cruising ‘chute. Photo shows Matt Newland in the first BR20 (I believe) at the Semaine du Golfe 2007 showing us how it’s done. Roaring around under full sail in winds that kept most people reefed down.  Wiped the floor with the opposition, that day in no mistake!

Have a good look at the sails in the following two clips. Even in fairly light winds the ‘chute gives the BRs a lift.

•   Caledonian Yawl by Denman Marine
 http://www.youtube.com/watch?v=QrY1CIuVj5A

•   Swallow Boats at Lake Bala by Matt Newland
 http://www.youtube.com/watch?v=tGwDhhMAp-M&feature=related


BTW:  Graham.  Dont be in a rush to increase the size of your mizzen!  With a following wind all that leverage so far aft can broach you if you’re not careful. Better to furl it away in a blow, especially as the BR 20 loves to surf off a wave.  (What’s the speed record so far?)

[Graham W]

Good explanation, thanks Tony.  So in Sail Caledonia 2013, all BR's just have to hope that the wind is NE and not SW (it is always one or the other, regardless of what is happening elsewhere).  Unfortunately, cruising chutes are not allowed in the race, otherwise I am sure that all the BR's would have used theirs this year.