reefing points of a cat ketch

Boat Systems
1

My first post of the year, so Happy New Year to all!

When I got the new sails made for Nausikaa, I asked the sail maker to fit two reef points on each sail, main and mizzen, which he did. I now realise I could use a third reef on the main. Of itself, not a difficult thing to do.

Functionally however, the existing reefs don’t seem to be in the right place. The first reef is quite low, and I hardly use it. The second reef is fairly deep, and with both sails on the second reef, I end up with equal (if not slightly more) canvass aloft on the mizzen as on the main, which intuitively seems incorrect on a ketch.

On resetting the reef points, it seems to me I should not only consider the geometry of each sail individually - aware that these things do not necessarily scale in direct proportions- but also the balance of both main and mizzen on each practical combination of reefing points.

I wandered if anyone in the forum had to do this, and what ratio or algorithm was used to calculate where the reef points should go.

Any input much appreciated!
Rafa

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Rafa,

I think you have a centreboard boat in which case balance may be slightly important but for long-keel boats it hardly matters - within reason. The original descriptions of the F40 CK centre-boarders said that the easiest reef was to drop the backsail.

I have two reefs on each sail however the backsail wishbone is not strong enough for the second reef so I have a complicated but effective method for it. I should really write this up some time as the sail has been fine in gusts of up to 50 knots by which time the boat is quite lively under this alone. I sometimes leave it up for days and nights on end at anchor. I mention this as your proposed third reef may bring the clew rather far forward on the wishbone - is it strong enough?

Have you tried hoisting the front wishbone to normal height, pull the tack reef line down to the SECOND reef then tighten up the FIRST clew reef line. This keeps the sail off the deck and brings the aft end of its wishbone low so it’s less likely to bash the back wishbone while tacking. Worth a try but it will depend on your sail. See my post of Sun Nov 27, 2016.

If there is any interest, I’ll post more photos.

3

Happy New Year, Rafa,

Do you still have the G10 rig, or have you gone back to wrap around sails?

In either case, I think it is important to maintain the same angle of the wishbone to the horizontal with each reef hauled in. This allows the sheets to run the same, gives the same clearance to the mizzen of the main wishbone, and keeps the part of the sail below the wishbone properly set. That last is important since it is also the ‘vang’, holding the wishbone down, and is still usable to give drive when all of the upper part has been dropped; a very small reefed area and very low on the boat, both ideal in stormy weather. The one time we hove-to in a gale, we had two reefs in the mizzen and just the lower part of the main set, and this kept us safe all night. I have sailed with three reefs in the main and the mizzen handed; this gave only three knots with the apparent wind at 45º, or seven with the wind on the beam, but that was going in the wrong direction (Inverness, not Lerwick).

When we last got new sails (wrap around with zipped pocket, not double ply overall), I only had two reef points put in each. and rarely reeve the second line since we do not head for open water with a poor forecast. If I were going across oceans, I would have a third reef in the main, but that is unlikely now. The PO, who did cross oceans, said if things got very rough, he would either lie a-hull, or else run downwind under bare poles trailing long warps astern, if there was sea room. I met another owner who recommended a parachute sea anchor, but you don’t make much progress with one of those.

If you still have the G10 rig, it would be interesting to hear how you fix the tack of the reef; parrel beads, or a downhaul on the forward part of the wishbone?

Regards,
Gerald

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Good morning Mike, Gerald
Many thanks for your reply! I’ll answer and comment both your posts in one reply.
Yes, I have the G10.
One characteristic of the G10 is that the luff is attached to the mast with a continuous line (I use a strap of polyester webbing) wrapped around the mast in a spiral, going through eyelets spaced evenly on the luff. Gio calls this a rakbanden in Dutch.

I’m happy with it the hole system. It’s a bid fiddly to set up, but once that’s done, it’s adjustable, dead easy to use, and I can drop my sails in -literally- 3 seconds. Just unclutch the halyard from the cockpit and let go; the sail will come down like a tonne of bricks with zero friction. I also have single-line reefing, with small blocks on both the luff and leach of the sails.

One limitation of the rig (rather, my incarnation of it), is that the wishbone collar choke interferes with the rakbanden, as one (or more, depending on how high I carry the wishbone) of the loops invariable goes over the boom choke. In my particular case, I have it set so that, in normal conditions, I can put the first reef without changing the height of the wishbone, as the the reef point on the luff remains higher than the boom choke on the mast relative to the horizontal. The second reef requires that I lower the boom about three feet on the main, maybe two feet on the mizzen. This is necessary to keep the sail shape, so that the effective foot of the reefed sail will be horizontal.
The flaked portion of the sail, on either reef, is held in a webbing cradle in between the arms of the wishbone.
This is what I did to build the cradle: https://www.freedomyachts.org/viewtopic.php?f=64&t=13050

Now, all this is well and good. However… my sails are quite roachy and have a lot of twist. Judging from the tale tales, when beating, the tractor part of the sail is roughly the middle 3 fifths of it’s height. The top fifth is under-trimmed because of twist, and the bottom fifth is overtrimmed, so I guess generating little lift and far too much drag. I think this is one of the reasons why Nausikaa jut refuses to move pointing above 45 degrees to the wind. I just can’t get my sails any flatter than that.
In reefing and to “secure” the reef, once the sail is at the correct height on the mast, I go forward, unhook the luff line (which by now is not tensioned), and attach a set-length line to the reefpoint with a carbiner hook. Tighten the rakbanden a little, re-tension the halyard, and presto! I have two such set-length lines, one for each reef, tied to the mast base ring.

None of the above is the cause of the problem, I think. With both sails on the second reef, I have to much cloth aloft on the mizzen. Ok when beating, but on reaching, the mizzen shades the main considerably and makes the boat difficult to steer. Remember coming into the Harwich channel, deep reefed, on a broad reach, with 35 knot gusts and following seas, and Nausikaa’s ass was dancing a salsa worthy of Strictly Come Dancing!

So… I need to put reefs on my sails in places where I can maintain both sails as balanced as possible, in all/most points of sail, and keeping in mind the “3-fifth-of-height” tractor component which seem to be inherent to the geometry of the sails and the rig itself. I was hoping there could be a rule of thumb or algorithm I could use to calculate where those should go. Perhaps finding out is one of those trial and error things?

BTW, for VERY bad weather, I have a small storm trysail for the mizzen. Never used it, hope never will.

Thanks again for your input Gents.

Rafa

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I have gotten a couple quotes to replace my sails.
I had decided after sailing for five years I need the second reef point only. We have found full sail until we put a second reef on the mizzen and the next step furl the mizzen and go to second reef in the main.
Maybe a third reef for balance or as squall sail.

Only time caught wth 25-40 knot squall with 60 knot leading edge I would have prefered all sail stowed in cabin… I never got storm sail out. It has only been up for demo.

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Rafa,

I just came across this Powerpoint presentation by Gio Schuten; don’t know if you have seen it. It does show where Gio put his reef points which may help you. “Samiel” is an F35, not a 30, but I am sure the proportions will be the same.
Sail plan F35 G10 type Rev 01.ppt (2.9 MB)

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Above attachment is some kinda scam thing…don’t click.

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Hmmm… Castaway’s attachment is good to me. Great power point pdf

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I don’t think there is any kind of scam; I have had this file on my computer for years, and originally downloaded it via this site. I have had no problems arising from having opened it. The author is Gio Schuten, who designed the rig and is a well known sailor in Nederland. I have looked through it again and it contains no links to any other site, nor does it offer anything for sale.

If there is a proven problem, please let me know and I shall modify or remove it.

Gerald Freshwater.

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Gerald,

Rest assured, there’s nothing at all wrong with that file. It’s a normal PowerPoint presentation with no macros.

Andy