Anonymous wrote:

Hi Paul,

No need to say that my twin keeled, heavily built kingfisher 20+ is not a race animal. Nevertheless, I find also that the groove on Shui Jen is quite narrow and I like to squeeze out of her as much as I can.  Junk sloops are cat rigged and I sail her as a laser…now, when I started learning sailing on my laser the instructor (a former laser racer ) explained me that the groove is a fluid concept. The wind has no steady direction but swings constantly like a pendulum. Its oscillation is not symmetrical and every regatta field on the upwind leg has a good and a bad tack: on the good one the wind swings  more frequently to windward. On this tack you can luff up more frequently than on the other tack and sail accordingly higher (closer to the mark). Moreover, the wind oscillates also in his strength and when it strengthens, the vector of the apparent wind moves astern meaning that you can luff up again. Anyway, after an acceleration as your speed increases, the same vector will move in the opposite direction meaning that you have to bare away again…of course to this should be added the motion of the waves (one should luff up while climbing up and bare away while sliding down the wave in order to keep the boat going). I think that this concepts can apply not only to lasers but to every cat rigged boat including a junk rigged sloop. Of course on cat rigged racing dinghies must be trimmed also weight, camber and twist…anyway, the groove to me looks like a lively moving snake :) Following it properly deserves a lot of attention and practice….

cheers

Mauro 

Bonjour Mauro

These notions apply to all type of riging, not only cat boats.

Eric

I'm very sorry, Mauro, for if your explanation is correct I used the word "groove" in a wrong way. 

Nevertheless, I understand your point, and fully agree.

What I meant with "groove" was basically the alpha-tolerance of the sail, to use technical terminology. In other words: how sensible is the sail to a change of angle of attack to the wind (of course the apparent one). The "groove" as I meant it is the width of alpha, at which the sail is drawing at maximum or almost maximum (there is no real border).

For example, a wingsail is determined (due to its nose radius) to have a much, much wider "groove" - so a much higher alpha-tolerance - than a single-ply sail like i.e. sewn-in cambered rig, split rig, Aero-rig, etc...

Cheers

Paul

Arne, 

Happy constitution day, and all the best to the norwegian people!

Excellent points of yours! I also find the groove of optimum angle of the junk sail to the wind quite narrow: I'm mostly either pinching or sailing too low. I think it doesn't help to have webbing sewed in at the luff - I expect boltrope would widen that groove. Anyways, the sail is now as it is, but I'll take it as a learning for the next sails.

You remember that tufting experiment on Ilvy last summer? Those telltales, spread all over the sail, definitely helped a lot - though I could only see the lee side telltales of the sun was on the right side. Sewing in some telltale windows would help here, but then we are talking about some fancy-schmancy regatta stuff :-D

I fully agree about the importance to give enough time to accelerate after a tack!

Today we had pretty much exactly the same conditions in the Kiel fjord at the regatta on wednesday: NNE F4-5.

I headed out for some training, trying to stay in the groove while sailing upwind. Turns out, Ilvy's tack angles/ angles to windward werr still not too good. What did I do wrong? How did I manage to get to almost 90° in Sweden last summer?

Then I got distracted from shooting some videos of the tacking manoevre of a junk rig. I did a lot of tacks, but focussed on filming. After that session, routinely checked my GPS track: Wow! Now this is what I had expected while racing: almost 90° in every tack. Was it possible, that I sail better angles if I didn't focus too much on steering!?

What an unexpected result...

Cheers, Paul

(Find the according screenshots attached)

Hi,

this summer I'm trying Ilvy for her racing abilities. Two days ago the first wednesday regatta of the season took off. Starting at 1800, it is a fun afterwork regatta, divided in three yardstick groups (The winner of each group has to buy a box of beer for the next regatta!). Ilvy, a Maxi 77, sails at yardstick 116 with her original bermudan rigg. I registered with that yardstick for the races, to be able to evaluate a possible yardstick modification by the end of the summer. Of course my hopes are high that Ilvy's yardstick can be reduced with the junk rig! :-)

Let's see how my enthusiasm compares to reality... I am not an experienced regatta sailor, and sailed maybe 10 regattas in my life, some on Ilvy with her bm rigg. I have to admit that I needed to look up most of the applying regatta rules on tuesday night.

The first regatta was raced at northeasterly F4, which means a lot of choppy waves in the Kiel fjord to sail against. Typically, the prevailing winds are westerly, sometimes easterly. Northerly is rare. I sailed single-handed this time, with the boat pretty empty - all the travel stuff from last summer was already cleared out in winter.

I had a superior placement at the starting line, just by letting the sail feather in the wind and waiting to the signal. However, in lack of a good timekeeping - I only used my phone showing minutes, not seconds, to start signal - I missed accelerating in time, and was overtaken by my whole group right after the signal, which left me last.

The first leg was upwind, and I saw those folkeboats (almost the same yardstick) slowly sailing away from me. I don't really know what I did wrong, but my GPS track clearly shows that my pointing angle wasn't good. I expect that against the choppy sea, Ilvy's round belly didn't stand a good chance, while those S-shaped longkeel folkeboats simply cut through the waves. Also, I oftenly pinch too high with the junk rig, only sailing by feeling - but when she uprights herself, it is of course too late... Maybe I need to put some luff telltales onto that yellow canvas! Pinching in choppy seas doesn't make one win a race, I guess.

Also, I kept on the eastern side of the fjord as I hoped to catch some nozzle effect of the northerly wind, while most other boats used the whole width of the fjord. Looking back at it, my strategy probably wasn't the best - though tacking really wasn't an issue at all.

However, once round the northerly buoy, Ilvy's time had finally come! Dead running, I shook out the one reef I had put in upwind, and she blasted through the water. I rounded the buoy together with one other competitor (not folkeboat), but downwind that boat was pretty soon left on the horizon. However, the folkeboat fleet was way too far ahead to catch up. Anyways, doing 6.5 kn downwind, with the tiller between my knees, I opened myself a beer (non-alcoholic) and enjoyed the ride anyways.

Result of the day: I was second last through the finish line, but 12th out of 12 yachts according to calculated time. Not exactly what I hoped for, but with potential for improvements!

To Do's for next time:

• more weight on the windward edge -> friends are already invited!
• less pinching -> telltales are already fabricated!
• use of accurate clock for the start

I had hoped that the rare northerly wind would be advantagous for the junk rig, as it set on leg to straight downwind. However, I hadn't considered the upwind leg being so choppy.

Let's see how westerly winds would suit Ilvy in that regatta!

Cheers,

Paul