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Old 17-05-2014, 05:42   #1
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Windward Performance - Genuine Tack Angles

When it comes to talk about tack angles and upwind performance, there are many claims. Some sound optimistic and perhaps embellished, some say only boats with dagger boards can sail up wind, whilst others have been rather derogative of certain builds/makes/boats.

Not for a minute do I think my L440 is a standout. To the contrary in fact. It's strengths lie elsewhere, like in blending space, quality finish, payload, price with moderate performance. I agree a lighter boat with dagger boards would clean me up.

What I would like to see here on the forum is some hard evidence, and it struck me that its not so hard to get. Here are two tracks from today's sail.

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The first shows my tacks to windward in 15-18 kts with full main and genoa. This was shallow bay sailing without swell, but with a 0.5-1.0m short chop. I was single handed, using the auto tack function of the autopilot (100 degrees) and as such was a little slow to get the genoa winched in and the heading tightened when sails set. Nevertheless, the boat tacked through the wind in 88 degrees at 7.5kts.

The second shows a single tack in 26kts of breeze with a single reef in the main and full genoa with 1.0-1.5m of short and steepening chop, with boat SOG being 8.5kts.

As for the ST60, the apparent wind angle was 30 degrees. I can skimp to 28 but with marked loss of boat speed and some early back winding of the main and genoa making this useful only to scrape past a mark if required.

No bragging here for sure, but this is what a heavy production mini-keel cat can do. Anyone else keen to show some data.
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Old 17-05-2014, 08:08   #2
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Re: Windward Performance - Genuine Tack Angles

Actually data. What a sneaky, underhanded approach.
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Old 17-05-2014, 08:09   #3
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Re: Windward Performance - Genuine Tack Angles

Those are some interesting data made more so with the graphics. But your data were collected under those conditions. I daresay if the wind was a little lower, you would find you could point a little closer into it. But if the wind was significantly higher, lateral slippage will mean you are struggling to hold a close reach, much less a close haul. So, I think direct comparisons will be difficult unless you have many boats together at the time (e.g. in a regatta).
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Old 17-05-2014, 08:20   #4
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Re: Windward Performance - Genuine Tack Angles

Impressive. I doubt that my boat, with boards, could do as well. If you had any regard for my feelings you would claim you had a lift from the current.
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Old 17-05-2014, 08:28   #5
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Re: Windward Performance - Genuine Tack Angles

Looks like you'll beat me to weather. Although that's not what I've seen when sailing along side Lagoons.
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Old 17-05-2014, 08:57   #6
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Re: Windward Performance - Genuine Tack Angles

Quote:
Originally Posted by 2Wind View Post
When it comes to talk about tack angles and upwind performance, there are many claims. Some sound optimistic and perhaps embellished, some say only boats with dagger boards can sail up wind, whilst others have been rather derogative of certain builds/makes/boats.

Not for a minute do I think my L440 is a standout. To the contrary in fact. It's strengths lie elsewhere, like in blending space, quality finish, payload, price with moderate performance. I agree a lighter boat with dagger boards would clean me up.

What I would like to see here on the forum is some hard evidence, and it struck me that its not so hard to get. Here are two tracks from today's sail.

Attachment 81455

Attachment 81456

The first shows my tacks to windward in 15-18 kts with full main and genoa. This was shallow bay sailing without swell, but with a 0.5-1.0m short chop. I was single handed, using the auto tack function of the autopilot (100 degrees) and as such was a little slow to get the genoa winched in and the heading tightened when sails set. Nevertheless, the boat tacked through the wind in 88 degrees at 7.5kts.

The second shows a single tack in 26kts of breeze with a single reef in the main and full genoa with 1.0-1.5m of short and steepening chop, with boat SOG being 8.5kts.

As for the ST60, the apparent wind angle was 30 degrees. I can skimp to 28 but with marked loss of boat speed and some early back winding of the main and genoa making this useful only to scrape past a mark if required.

No bragging here for sure, but this is what a heavy production mini-keel cat can do. Anyone else keen to show some data.
How heavily was the boat loaded when you did this? My Endeavourcat performed about the same before I started cruising. With the cruising load on board now I can only get about 60 degrees to the true wind not just inside 50. I also got new sails last year but also added a few hundred more pounds of gear. I don't know which had more effect on my pointing ability, but I suspect it's the new sails.
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Old 17-05-2014, 14:44   #7
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Re: Windward Performance - Genuine Tack Angles

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Originally Posted by Ded reckoner View Post
Those are some interesting data made more so with the graphics. But your data were collected under those conditions. I daresay if the wind was a little lower, you would find you could point a little closer into it. But if the wind was significantly higher, lateral slippage will mean you are struggling to hold a close reach, much less a close haul. So, I think direct comparisons will be difficult unless you have many boats together at the time (e.g. in a regatta).
Agreed. I'm sure every boat has a sweet spot as well as black spots. Being a heavy boat the L440 really needs wind, and flounders with anything under 5kts. It noticeably "lifts" when the wind exceeds 8kts and is happiest above 10kts. So at slow wind strength the lack of forward motion facilitates slip which is where boards would be a great help. Above 25kts, or with unfavourable sea states, the limits of hull speed comes into play and the boat is relatively too slow for the wind and slips. So perhaps the examples shown are in conditions favourable to the boat. (mind you - nice, comfortable average conditions).

Last month when cruising along side with the Brisbane to Gladstone race fleet, we faced unfavourable conditions off the Breaksea Spit (North Fraser Island) with 5kts of wind and the 3-4 kt Great Australian current on our nose. Our tack angles were more like 120 degrees then.
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Old 17-05-2014, 14:49   #8
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Re: Windward Performance - Genuine Tack Angles

Quote:
Originally Posted by Ded reckoner View Post
Those are some interesting data made more so with the graphics. But your data were collected under those conditions. I daresay if the wind was a little lower, you would find you could point a little closer into it. But if the wind was significantly higher, lateral slippage will mean you are struggling to hold a close reach, much less a close haul. So, I think direct comparisons will be difficult unless you have many boats together at the time (e.g. in a regatta).

That's exactly the opposite to what I've found. In lighter winds I'll sail lower, stronger winds higher.

In less than 10 knots wind we'll sail at 32-33 apparent, in 10-15 it would be 30 degrees, in 20 we'll sometimes sail as high as 27-28. (Angles set on the autopilot steering to a wind angle)

In light wind our boatspeed compared to windspeed - around 75-80%means we'll tack through a fairly big angle too - 100 degrees or more. In higher winds, tacking angles are better, due to boatspeed being a lower percentage of windspeed.

One very enjoyable upwind sail we had was in flat water and ~20 knots of wind in lake Macquarie. We were sailing at 11 knots at 29 apparent. Loved the flat water! Tacking through a bit less than 90' IIRC.
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Old 17-05-2014, 14:57   #9
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Re: Windward Performance - Genuine Tack Angles

Oh no, I have just seen real data. I obviously have been sailing in the Nile denial.
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Old 17-05-2014, 15:05   #10
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Re: Windward Performance - Genuine Tack Angles

A couple of our tracks on a loaded Lagoon 380, similar experiences. Both were beating into 1m - 1.5m short seas.
The second was around a headland with a few knots of current against us. You can see the effect on the angles!


Both times most of the other boats (all mono's) were motoring along the direct course and most of the time we were close by as we tacked past them...
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Old 17-05-2014, 15:09   #11
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Re: Windward Performance - Genuine Tack Angles

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How heavily was the boat loaded when you did this? My Endeavourcat performed about the same before I started cruising. With the cruising load on board now I can only get about 60 degrees to the true wind not just inside 50. I also got new sails last year but also added a few hundred more pounds of gear. I don't know which had more effect on my pointing ability, but I suspect it's the new sails.
Bill, I think my L440 is relatively light (by choice). No genset, no air conditioning, half fuel (325 litres), half water (450 litres), single 15HP outboard for tender, no toys and few supplies. (I cleaned out all the lockers recently and off loaded so much unnecessary crap). Oh! and one crew still having fun despite such deprivations.

Sails are 2 years, Hydranet triradial cut. I'm sure sail shape is critical.

Although not done in the examples given, I will on occasion in light wind, use the lazy genoa sheet as well and haul the clew to windward by a foot as the traveler position is in a "compromise position". Surprisingly, by narrowing the slot and reducing backwinding the genoa luff this does make a difference but the wind needs to be under 8kts as the loadings on hardware need to be respected. Also, I don't use an outhaul on the main, whit the clew simply tied off in a firm position. I've thought about it as I could easily use the 3rd reef line from boom end for this purpose. I have thought it would make little difference but who knows.....

Anyway, I don't want this to be about my boat. I'm hoping others might think about showing their data. Just take a screen shot of your track off your iPad or iPhone Navionics or other software. I'd really like to see what is achievable out there in the real world.
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Old 17-05-2014, 15:31   #12
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Re: Windward Performance - Genuine Tack Angles

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A couple of our tracks on a loaded Lagoon 380, similar experiences. Both were beating into 1m - 1.5m short seas.
The second was around a headland with a few knots of current against us. You can see the effect on the angles!


Both times most of the other boats (all mono's) were motoring along the direct course and most of the time we were close by as we tacked past them...
Monte,
Thanks for your data! "Real life" data!
Many of the tacks look to be near 90-95 degrees too. The less favourable ones, I'm sure, will reflect sea state and current. Also, on the two longer STBD tacks on your second graph, show what I suspect is wind shear. The closer you got to land the better your VMG.
Nice examples. Jealous about your exotic location!
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Old 17-05-2014, 15:33   #13
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Re: Windward Performance - Genuine Tack Angles

Love those plotter shots.

Whenever I am feeling really happy, happy with the world, happy with myself, running and jumping and smelling the flowers I have a look at some of my plotter shots. Brings me right back to earth.





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Old 17-05-2014, 15:54   #14
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Re: Windward Performance - Genuine Tack Angles

We know you had the leeward engine on. Give it up!
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Old 17-05-2014, 15:54   #15
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Re: Windward Performance - Genuine Tack Angles

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Love those plotter shots.

Whenever I am feeling really happy, happy with the world, happy with myself, running and jumping and smelling the flowers I have a look at some of my plotter shots. Brings me right back to earth.
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Good idea. I guess its much better than taking Lithuim for your periods of mania. Too much joy cant be good for you.
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