Daggerboard - use of?

This might seem like a silly question, but the daggerboard/centreboard is moveable for a reason. However, after a couple of inversions where the daggerboard dropped completely out of the slot, I have started to sail my boat with the board fully down on all points of sail. I've checked my speed using GPS, and can't find much appreciable difference with the board fully down, or otherwise.

Training tells us that the board should be fully down when beating, half way up when reaching and up when running. Long established classes such as the Wayfarer (and especially Laser) for example, seem to follow these rules.

But, I've looked into this further and found that some more modern classes (e.g. RS, especially those with bungee which goes over the top of the daggerboard when it's fully down) don't seem to bother raising the daggerboard once the water is deep enough after launching. My current race training has also highlighted that the daggerboard should be lowered *before* the gybe mark - something that I've never had the nerve to do, but so far I haven't had any bad experiences!

1. So, is gybing with the board down a bad idea?
2. Stability on the run is improved, but as for the boat "tripping over" the board as it gybes, does this really happen?
3. Is it really worth moving the board up and down for different points of sail? The increase in drag can't be that much, can it?

Any thoughts/suggestions please!

It really does depend on the class of boat that you sail.

In a laser when its really blowing I usually leave the board 3/4 down to make it easer to keep it flat on the beat.

In anything assy i never take the centreboard up (mostly due to lack of arms/ability to keep the boat flat) but i have seen it done in RS400s

Apart from that i normally follow the guidelines

As said, at the level where it begins to make enough of a difference to your performance, it really depends upon the boat. Skiff-type boats tend to leave it down for several reasons:

1. Not enough time/too much sideways pressure to adjust it during bearaways and round-ups
2. different sideways forces may require the board to be down
3. less for crew to get caught on- not so much space on an RS800 especially once you figure in the centre main sheet and traditional kicker

as far as I can figure out, anyway. Sone do have levels to bring the board up a bit in high winds (at faster speeds, the losses of lift are offset against less adverse righting moment for overall greater efficiency) especially on flat water- in waves, there's more chance of stalling the foil.

Raising a centreboard does different things to raising a daggerboard. Raising a centreboard moves the pivot point of the boat aftwards. What this does is increase lee-helm. This helps the boat point deeper downwind more efficiently- very useful with a traditional spinnaker or the canting bow-sprit of the RS400*. Raising a daggerboard significantly (like on a Laser or Topper) does do this somewhat as well, though not to the same degree.

If you find you have a problem with the daggerboard falling out on capsizing- do you have a bit of elastic pulling it forward? On a Laser, you should have a length taught through the front of the board and round the front eye on the boat, running either side of the mast. On a Topper, there's a single line that should go round the mast and clip to itself. On both, this holds the top of the board forward in the case, meaning it shouldn't drop down when there's no side-load on it. That should stop it falling out when inverted, or at least leave enough sticking out for you to grab and pull the rest out.

As for speed- absolute speed is not the key in racing, it's what's variously reffered to as Speed to the Mark, Speed Made Good or Velocity Made Good (VMG). Two boats at the same absolute speed can have very different VMG.

I'm bound to be corrected on some technical points here, and look forward to being so. We all never stop learning.

*had a go on one last week for the first time- they point scarily deep. It's just un-natural if you're used to more conventional systems...

Edited by alstorer

any RYA trining teaches you to have the board as suggested. however in the 600 i only bother to raise it on dead runs in the light stuff, otherwise there isn't enough time, and the boat gets even less stable, and its harder to bring the boat upright after you do piss it in.

As for centreplates, im not really sure about why but i know when i used to crew in a fireball when it got windy we swung the board back more for upwind to match raking the rig back i think.

I've investigated this a lot from a newcomers perspective.

Coming as I do from a world that dumps the plate totally the moment the
board planes offwind and rakes it a tad aft in windy weather to prevent
'railing' (the board tilting up on its edge like a boat heeling)

As usual depending who you ask you get conflicting advice, we ruined
half a season in the RS500 arguing over kicking the plate after an ex
scorpion helm had a go whilst i was away one weekend and immediately
kicked the plate back impressing jumanji, but he was on a two sail reach
which is fine, but the moment you put the kite up, you're best off leaving
it down, because the centre of effort shifts so far forward with the kite up
anyway.

I think alstorers explanation rings true, our Alto will go deeper with the
plate kicked back, especially with the pole canted to weather, but you do
induce lee helm.

We've yet to dump the plate totally, it's another control on the to do list,
bringing the method to do it to the helm. Usually by the time we could do
with it, we're fully wired and flying..

We knocked it back a tad on sunday upwind, investigating just how much
faster we could be sailing lower and faster up wind, it seemed to work, we
stretched our legs a fair few boat lengths from a nearby 505 that had
appeared to be catching us.

Edited by G.R.F.