What percentage reduction in sail area is 1st and 2nd reef

[ProDave]

Very interesting topic indeed.

I don't think I can add anything, but I would like to throw in my personal experiences to add to the debate. but bare in mind i'm not an experienced sailor and only day sail a small boat.

Anyway my point is, my little boat does not have reefing points on the main sail, so it's all or nothing, something I have not yet got around to putting right.

So when I'm out sailing and it starts to get windy, my "first reef" is to furl the forsail away and sail on main only. so that (roughly) halves my sail area. If that's still too much sail up then I'm afraid it take the sail down and put the motor on.

But my point is, I seem able to sail until I feel over powered, then halve my sail area and carry on sailing.

so to me, a first reef should be a 50% reduction in sail area. That's more like what you are talking about as a third reef.

I'm not trying to say you are wrong, but my findings would suggest I wouldn't notice much difference with a 20% reef, and would quickly be putting in the second or third reef.

One other little observation. I have the cheap Barton roller furling gear on my foresail. Accepted belief is that is all or nothing. But I have tried it, and it seems perfectly possible to partly reef the foresail with that. So why do people say you can't reef the foresail with that system?

 

[davidej]

OK. Show me calculations and diagrams that show the CoE moves the same amount for each scenario. Or can you cannot readily write some logic?

Sorry to be a bore (or boor) and continue this arguement.

If you assume the sail to be triangular (and I admit a roach might make a slight difference) then whether you take 10% off the foot or off the luff, you end up with a similar (ie same shape) triangle with each side 10% smaller - and the area 19% smaller.

And the triangle ends up in the same place ie the tack in the same place and one edge along the mast and one along the boom.

No calculations required!

 

[Lakesailor]

I have worked it out and you are correct.
However lots of other good points are made in this thread about it not being a comparable measure.

 

[rhinorhino]

So I have in-mast furling (no debate to be started on this). I can reef as much or as little as I like, but there are no reefing marks as there are on the head sail.

Is there a standard amount for sail reduction for headsail or mainsail 1st and then 2nd reefs.

If I wanted to mark my sail for those reductions how would I calculate where to put the marks?

TudorSailor

MCA (coding requirement is 40% for 3rd reef.

Just a thought, but would not fixed marks lead to mote chafe/wear around those areas and loose the flexibility of in-mast reefing?