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Old 04-05-2016, 05:03   #31
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Re: Polars building

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Originally Posted by arsenelupiga View Post
say this one i sailed in med, elan impression 434. cannot do 8kn at 50 deg true at any wind speed
http://www.elan-yachts.net/img/yacht...ar_diagram.pdf

Yep, the Elan surely doesn't have a surplus of speed/performance. And also, if you ever want to compare boats, try & get their racing handicap ratings. Such as those in the PHRF system, it's a Performance Handicap Rated Fleet, so that each design has a base rating, but the rating for a particular boat gets "tuned" by the local board, based on how well they do.

However, the base ratings are created around how well a particular design sails over a whole variety of courses, in every different kind of wind condition & sea state. PHRF New England - Handicapping - Base Handicaps

The Aerodynes, while racy, can definitely be cruised. Take a look at their interiors, amenities, & equipment levels. Aerodyne Yachts Ltd. And the 38' won Cruising World's Boat of The Year award for best Racer/Cruiser.
I snagged them as an example, as it was someplace that from memory where I knew that I could find Polars online.

That said, when such boats are setup for distance racing, they will have a minimum of 6-8 crew (often more). Along with 3-4wks provisions. A decent liquor cabinet. Plenty of beer & sodas. Plus a good dozen or so sails.
Also, full safety equipment, critical equipment spares, etc. Just like a cruising boat.
So, a ton & a half, maybe more. Depends on the race, & the crew (meaning what level of spartanness or debauchery they're wanting to have).

benetaus probably same. Your boat has great performance, but probably not intended for extended cruising.

Regarding your questions... I have taken all on board. My plan when in similar conditions 13 kn wind + and not too rough will be in this order:

1. calibrate speedo above 7.5kn. I can do around 8.5 motoring, so at least will get extra knot or 2 of correct measurement.
Yes, calibrating it's a good idea. Especially when you do it over a full range of speeds, not just the higher ones.
Though it isn't too tough to drive yourself crazy, trying to get your instruments calibrated "perfectly". Thus my earlier comment, that getting your speedo within 0.2kts on all headings is pretty much good enough.

2. flatten sails - level of optimal flattness for wind around 11 kn differs when wind 15 kn or more - that is my theory at least
Generally, & this is for upwind, mostly: 0-6kts you want them flat. 6-15kts deepen their draft. 15kts+ start to flatten the out, to depower them.

Off of the wind they can have more draft, but generally speaking, you don't want them to look like "D-Cups". As even downwind a lot of your drive comes from the lift which they generate. And fat sails = higher drag, generally.

Do some experimenting with your sail trim, & record the settings of the sails vs. boat performance, in order to get a more accurate set of charts.
And some of the "settings" thing, is where having a practiced set of eyeballs onboard to gauge such is helpful.

3. I have made couple of mistakes - my jib was set too full at the time - too much sag. My luff was too lose on main and jib.
If you want to get serious about being able to set your sails "properly" for various conditions. One "trick" is to mark the halyard or control line with a waterproof marker. And to buy, or mark off scales, as in literally like a yard stick/tape measure, on the mast, boom, or deck.
- That way, your settings are easy to; see, note (log), & also to repeat.
When you start doing that, & get to where you have a database of notes, your performance will go up a fair bit.

4. verify no bow wave under hulls stopping boat at around 7.5kn. This is a showstopper.
You're always going to have a bow wave. And ideally, you'd have someone on another boat video taping it under various conditions. Though my getting into analyzing such things would take far too much text.
Once I exhaust above, and no answer

5. balance boat - my sterns are too low and water does not exit nicely.
Slightly dragging transoms is okay in light air, 0-5kts, but after that, it tends to slow the boat in a geometric proportion to her speed.

6. Sails have 17k miles, so maybe thats the issue
Yeah, definitely. Especially if they're Dacron. But post some pics. Particularly from the perspective of you laying on your back, & looking up at their draft & shape when close hauled. That, & or video. Upload a few onto YouTube, & put the links on here.
Also, refer to the earlier post on this. Re; steal some racing talent for such analysis, ditto on a sailmaker.

then I will reread what you wrote to get more ideas.

what do you say ?
I hope that the above helps. And learning/putting these things into practice, will help. Especially when you get to where you start explaining them to others. As for me, when people start asking me questions about why X, & Y are done a certain way, I learn huge amounts about the topic both during the exchange, as I'm forced to think up my answers. And also later on, when I go & study on the stuff more.
And that's not just sailing habit. I do/have done, the same with performance driving, or stuff to further career goals, etc.

Regarding which, there are some great books out there. Which help to speed up one's learning process a lot. Coaches & classes are an aid too.
And me, I keep said sailing "textbooks", plus my notepad, in by seabag, & or on deck. And I highlight things in both using various different colors. Make notes in the margins. Taking them with me when I go to ask other sailors questions on topics X, Y, & Z.

But then I've always been preternaturally curious. Ever since I was big enough to wiggle across the floor, & go investigate the world
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Old 04-05-2016, 05:15   #32
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Re: Polars building

thank you ! Will do as you say.
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Old 04-05-2016, 12:53   #33
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Re: Polars building

No problem. Good luck!
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Old 04-05-2016, 13:02   #34
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Re: Polars building

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Originally Posted by arsenelupiga View Post
8 kn in 14.5 kn wind true at around 32 app, in full cruising gear, based on your screenshot. This is 5.23 VMG. Drift would be very small if at all at this speed. Presume near flat water.

That looks pretty impressive. Will keep that one as a benchmark to see how I progress.

quick look thru cruising monos polars reveals that at 50 angle 8k with 15 kn wind is a bit of challenge.

hard to imagine how slow they get when loaded fully. And considering these polars are bit of fantasy in first place, so one can subtract 1 kn to get real polars.

That might be overstating the performance a bit. I wouldn't rely on the log for too accurate data. It tends to change a bit depending on the tack. There's probably more pressure when the log is in the leeward hull and more speed indicated. Leeway is around 12-15 degrees in those conditions. Yes nice flat water, small rolling swell that didn't impact speed at all.
Try playing around with the VMG setting on your displays. VMG to wind will probably fluctuate a lot, but if you place a waypoint 20 miles upwind and set VMG to that waypoint the readout will be a bit more consistent and usable.
There's not much tweaking involved when we sail. We rarely touch the traveller, just leaving it centred. The only adjustments we make are sheets and jib car position. Upwind the car is first hole forward from fully back usually, jib sheeted till it almost touches the spreader, main sheeted in hard, usually on autopilot in wind vane mode at between 33 and 40 degrees depending on the wind and sea state. Occasionally hand steering in really sloppy stuff.
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Old 04-05-2016, 13:39   #35
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Re: Polars building

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That might be overstating the performance a bit. I wouldn't rely on the log for too accurate data. It tends to change a bit depending on the tack. There's probably more pressure when the log is in the leeward hull and more speed indicated. Leeway is around 12-15 degrees in those conditions. Yes nice flat water, small rolling swell that didn't impact speed at all.
Try playing around with the VMG setting on your displays. VMG to wind will probably fluctuate a lot, but if you place a waypoint 20 miles upwind and set VMG to that waypoint the readout will be a bit more consistent and usable.
There's not much tweaking involved when we sail. We rarely touch the traveller, just leaving it centred. The only adjustments we make are sheets and jib car position. Upwind the car is first hole forward from fully back usually, jib sheeted till it almost touches the spreader, main sheeted in hard, usually on autopilot in wind vane mode at between 33 and 40 degrees depending on the wind and sea state. Occasionally hand steering in really sloppy stuff.
i found that L400 goes better when sails are bit open, jib and main, including sharply upwind. Probably because creates less turbulence after air leaves sail. The other day i was matching several mono performance in 10 kn true at 35, in slightly agitated seas averaging 5k. I thought that was good. I was slightly gaining when true speed towards 12k and slightly staying behind when towards 8 kn.
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Old 22-05-2016, 02:08   #36
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Re: Polars building

another day another sail, another point of sail tested.

This time was around 7 kn wind, 50 app angle, using screecher.

i think average was 7.5 kn true and 5 kn boat speed. I smoked two 45 ft monos quite a bit. I think they bit underestimated our boat. Both turned away very sad and with hurt pride. I can see their polars look sparkling but real world is not flat water.

I managed actually in 8 kn wind, 5 kn boat speed at 36 app which gives around 2.6 VMG to wind and 58 true angle. Seas bit rolly but manageable. Flat water would sure be better. But flat water really rare occurrence where I live, so irrelevant.
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Old 22-05-2016, 23:23   #37
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Re: Polars building

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6. Sails have 17k miles, so maybe thats the issue


This certainly won't help! Especially if they're the standard slab cut Dacron sails. They'll say in one piece for much longer, but their efficient sailing shape would be long gone.

I gained 4' of pointing ability (according to the Simrad AP's VMG optimiser)by getting new sails. Optimum angle for VMG is now 28'.

The old sails had near 28k miles on them, and were stretched a fair bit, and coming apart slightly.

Beam reaching TWA ~ 90' yesterday in ~6-7 knots wind we were sitting on 6.5 - 7.5 knots boatspeed. GPS and log in agreement. Really liking these new sails.

Fully loaded too. In fact the old sails are still on board, so there's an easy 100kg that'll be gone soon.
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Old 22-05-2016, 23:52   #38
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Re: Polars building

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This certainly won't help! Especially if they're the standard slab cut Dacron sails. They'll say in one piece for much longer, but their efficient sailing shape would be long gone.

I gained 4' of pointing ability (according to the Simrad AP's VMG optimiser)by getting new sails. Optimum angle for VMG is now 28'.

The old sails had near 28k miles on them, and were stretched a fair bit, and coming apart slightly.

Beam reaching TWA ~ 90' yesterday in ~6-7 knots wind we were sitting on 6.5 - 7.5 knots boatspeed. GPS and log in agreement. Really liking these new sails.

Fully loaded too. In fact the old sails are still on board, so there's an easy 100kg that'll be gone soon.

sails may be the reason, but my trim skills are moving target at this point. Want to get good at trimming first else i will not be able to squeeze best out of new sail.

Looking at measurements that I wrote down over time, have improved at any point of sail for a knot to two give or take. And now mostly, outperform Lagoon 410 factory polars, except reaching in 12 Kn + wind.

In strong winds - 18kn+ , should squeeze 10kn + , i am hoping.

This exercise is to make efficient barber hauler(s) to improve sail shape where possible. However, don't anticipate to use whisker pole as it may get messier faster.
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Old 23-05-2016, 07:09   #39
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Re: Polars building

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This exercise is to make efficient barber hauler(s) to improve sail shape where possible. However, don't anticipate to use whisker pole as it may get messier faster.
Not sure whether it is the most efficient barber hauler, but it's simple; on ours we use a block and a dyneema soft shackle. This quickly attaches to either mid-side cleat. Twelve metres of 12 mm double braid tied to the genoa clew, through the block and back to a winch.

Great for giving better genoa shape when deep reaching or holding out the sail when wing on wing with the gennaker at about 160 degrees apparent.

Too much force on a barber hauler may damage a nice, new, unstretched, precision cut genoa. Luckily my old headie is none of the above.
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Old 24-05-2016, 00:03   #40
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Re: Polars building

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Not sure whether it is the most efficient barber hauler, but it's simple; on ours we use a block and a dyneema soft shackle. This quickly attaches to either mid-side cleat. Twelve metres of 12 mm double braid tied to the genoa clew, through the block and back to a winch.

Great for giving better genoa shape when deep reaching or holding out the sail when wing on wing with the gennaker at about 160 degrees apparent.

Too much force on a barber hauler may damage a nice, new, unstretched, precision cut genoa. Luckily my old headie is none of the above.
i have used for deep reaching as well.However, found that jib custom setting can be used way closer to wind and improve performance. Actually 1x reefed main is ideal playground as main sail shape can be better controlled. In around 10 kn winds have left behind other cats (not lagoons) with full sail trying to get easy win reaching and upwind. This setting great when wind strength varies a lot. The other I want to expand on is 2x reefed main & 80 % genoa in 15 to 45 kn true.

Here is what i do, using 3 lines to control jib shape, 3D movement, prototyping at this stage.
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Old 24-05-2016, 00:44   #41
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Re: Polars building

Its great to see folk optimising their boats, it is amazing how much better almost every boat can be made to go, and its rewarding to know you are getting the most of of your boat. You may want to think about getting a rigger to check your mast tune as well, it can make a huge difference to performance.

Well done and keep up the information, I am enjoying seeing how you go with your fine vessel.
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Old 24-05-2016, 00:57   #42
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Re: Polars building

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Its great to see folk optimising their boats, it is amazing how much better almost every boat can be made to go, and its rewarding to know you are getting the most of of your boat. You may want to think about getting a rigger to check your mast tune as well, it can make a huge difference to performance.

Well done and keep up the information, I am enjoying seeing how you go with your fine vessel.
sense bit of sarcasm, but thanks anyway. we have to do with what we have. And what we have depends largely on what out better half choose. Only then is my turn.

And I hope, can make the boat I have in fine passage maker.

Would like to understand rigging & weaknesses & strengths of my boat before trying to optimise and spend $$$. Cant say I understand at present.
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Old 24-05-2016, 01:14   #43
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Re: Polars building

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sense bit of sarcasm, but thanks anyway. we have to do with what we have. And what we have depends largely on what out better half choose. Only then is my turn.

And I hope, can make the boat I have in fine passage maker.

Would like to understand rigging & weaknesses & strengths of my boat before trying to optimise and spend $$$. Cant say I understand at present.
No sarcasm at all, genuine sentiments, I regularly see boats with sagging forestays and think that could go quicker and higher with a bit of a rig tune, or boats with too little or too much outhaul, such easy fixes, and no cost. And you may find as you apparently already have that you surprise a few other boats! And that is always fun.
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Old 29-05-2016, 05:11   #44
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Re: Polars building

i have found 3 potential issues that i will work on and hope to get some improvement

1. Mainsail luff. Double halyard is twisting therefore i do not pull sail to the top and luff is loose. Will have to sort out halyard.
2. jib luff - ignored it and kept it loose. Shape of jib is D like (see pic), which uncivilised mentioned no very good. I pulled it harder today and it appears made difference in speed but did not step any further in this direction. Need marker to have some reference.
3. need to flatten sails.
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Old 29-05-2016, 07:23   #45
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Re: Polars building

Re the main, have you tried a cunningham?
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