downwind sailing

SteveGorst

SteveGorst

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I have just taken my first step in club racing. My boat is an Etap 26 not the more modern 26i and during the race in brisk 15 knot winds we performed well closehauled to windward. We did however loose out once we turned downwind.

If we sailed the final leg directly straight to the mark the wind was directly astern. We chose to do this on a run, Goosewinged with gybe preventers rigged, but the boats we had pulled away from on the upwind section gradually hauled us in. I think we could definately improve next time by buying a pole and poling out the headsail but I also wonder if it would have been better to bear off a bit onto a broad reach and then Gybe back towards the mark.

Has anyone tried the two methods and come to a conclusion as to which is generally quicker.

Cheers
Steve

<hr width=100% size=1><A target="_blank" HREF=http://"www.nwcc.info">North Wales Cruising Club</A>
 
I've raced on a maxfun 35 which sits in the IRC 1 category (sometimes IRC0) All the boats have spinkers eith conventional or asymetric and always they sail on a broad reach downwind and put in a gybe. - It is faster, however when team racing in 420 dinghies we sail straight for the mark goosewinged.

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With a moderate displacement boat you will be better off with a poled out Genoa. Reaching will fill it properly in the absence of a pole, but it's not as fast.

You need a spinnaker!

<hr width=100% size=1>my opinion is complete rubbish, probably.
 
you will need to bear off as much as 45 deg onto a reach to get the genoa to draw effectively. to make up for the extra distance covered you will need to achieve a 40% increase in speed. this is usually only possible in lightweight mulithulls an planing designs.

get a pole!

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It depends on the type of boat, wind conditions and how wide the channel is.

The lighter the displacement the more appropriate it is to tack downwind. Only light, planing craft really benefit.

Assymetric spinnakers gain more than conventional spinnakers and white-sail-rigged boats.

In narrow channels gybing inevitably costs a little time and risks snarl-ups so it is less advantageous.

In your case a poled out genoa and a direct course in the answer but if you want to take your racing at all seriously, get a spinnaker.

<hr width=100% size=1>JJ
 
Here's one of my recorded polar diagrams, for a true windspeed of 11-12 knots. The plot is boat speed (radius, in knots) against true wind angle, white sails only.

11_G.sized.jpg


The best progress downwind is with the wind at 165 degrees true, which is 95 degrees apparent.

<hr width=100% size=1>One day, I want to be a real sailor. In the mean time I'll just keep tri-ing.
 
My experience is that it is quicker to pole out genoa and head dead down wind. This is the shortest distance to run (quite literally), and in any modest breeze you'll be approaching hull speed anyway (as you're not about to start planning anywhere).

As has been pointed out, gybing off down wind covers more ground and requires a proportional increase in boat speed to achieve the same time down the leg. The following gives extra distance (as rough percentage) against angle off dead down wind:

Angle/Percentage distance

0/0
5/0
10/2
15/4
20/6
25/10
30/15
35/22
40/31
45/41

as long as your speed increase is in excess of your distance increase you're a winner. Thats where Extraverts diagram really helps.

Regards, Jeff.

<hr width=100% size=1><A target="_blank" HREF=http://users.swing.be/FDB/centurion/index2.html>Centurion 32 Web site</A>
 
Broad reaching is faster than running and also means that you can play the waves a bit which can often bring your speed up compared with dead running. James says buy a spinnaker if you are serious about racing - very true but it won't half screw your finishing positions until you get used to it.

<hr width=100% size=1><font color=purple>regards
Claymore<font color=purple>
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Thanks for the diagram. I suppose this is dependant on the boat design but now you've shown me how to become systematic about rating my own boat and learning how to get the most out of it. I think the 5 degrees off the dead run will prove to be about right.

Cheers
Steve

<hr width=100% size=1><A target="_blank" HREF=http://"www.nwcc.info">North Wales Cruising Club</A>
 
extravert sails an extreme version of the light multihull which is fast enough to bring the apparent wind forward with even a few degrees off the dead run, the pronounced dip in the vector diagram at 180 degrees reflects this. the effect will be much less pronounced on your boat, if at all.

here is a way to very quickly and easily determine how much extra speed you need to pick up to make up for sailing off course:

1. take a sheet of paper, mark a point near the centre of the bottom edge. draw a line from there straight up towards the top edge with a length representing your current speed (e.g. 5 knots = 5 inches).

2. draw another line through the end of the line at right angles.

3. draw more lines from your starting point at various angles (10, 20, 30 degrees etc.)

4. the length of each of the lines to where it meets the cross line represents the speed you need to attain to get the same speed towards the objective.

this can also be done directly on your chart using your usual instruments and takes less than 30 seconds.



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V fast tri

People should be aware, extravert, that you sail a very fast, light, responsive trimaran which is a very differnt animal from the Etap 26 under discussion

<hr width=100% size=1>JJ
 
Better poling out the genoa or better still an assymetric kite maybe with a snuffer so that not only do you not have to faff about with a spinnaker pole but you can deploy and recover it easily, also you can get ones made that turn into great big reaching sails :D

We have tried the reaching lark when short handed and it doesn't pay off unless you make (as mentioned before) at least 40% more speed which in our experience only happens when it's a bit blowy, in which case, you'd be better off downwind anyway.

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