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Old 19-12-2015, 08:19   #91
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Re: Going hard to wind, main sail trim.

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Originally Posted by thomm225 View Post
Now you are playing word games. Okay!

You flatten the mainsail to depower which reduces it's efficiency while give the boat better upwind performance toward the mark.
You're both right.

A flatter sail will produce less lift. But it will produce less drag as well.

On most points of sail, you don't care all that much about drag. With the apparent wind behind the beam, drag is actually helping you. So you will trim the sail for maximum lift without caring as much about drag.

But going hard upwind, with your COG vector close to opposite the wind vector, drag is slowing you down and setting you off to leeward (creating leeway). Drag is the enemy. So you give up some lift, to reduce drag, by flattening the sail.

Unless you have very good sails, you probably won't be able to get the sail flatter than optimum for going hard upwind. With very good sails, there is a point where lift falls off faster than drag and you lose efficiency -- that is "putting the mainsail to sleep". But up to the point where lift falls way off, the sail is MORE efficient, being flatter, because net power -- efficiency -- is the balance of lift minus drag.
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Old 19-12-2015, 08:54   #92
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Re: Going hard to wind, main sail trim.

Great posts, Dockhead, very well written, too. A good primer for sailing upwind in heavy air. Thanks. This comes up so often, you oughta save it for the next time.
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Old 19-12-2015, 09:25   #93
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Re: Going hard to wind, main sail trim.

Looks like the OP has a Viking 30. If this is his actual boat (see sailboatdata link below), it's going to be a bitch to get it to point in 20 knots at all much like my Bristol with it's long keel.

Usually when I'm in 20 knots plus, the waves are large and close (4' - 6') so I have to fall off so far just to get through them that all pointing goes out the window.

Many times I'll use the forecast and sail to the side the wind is rotating to then tack and head home. I'm crossing a 20 mile bay though whereas the OP was talking the last 3 miles.

Plus going by the picture he has an old style long power creating boom with a long keel not a shorter boom for speed with fin keel

And the boat displaced 18,000 lbs! A 30' boat!

Now, that's a cruising boat...............(disp./Len:581)

Viking 30:

VIKING 30 sailboat specifications and details on sailboatdata.com
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Old 19-12-2015, 10:05   #94
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Re: Going hard to wind, main sail trim.

OP said boat was designed by Lexcen. It's going to be the opposite as an IOR raceboat.

Viking 30: Sailing Boats | Boats Online for Sale | Fibreglass | Western Australia (WA) - Claremont Wa

Quote:
Originally Posted by thomm225 View Post
Looks like the OP has a Viking 30. If this is his actual boat (see sailboatdata link below), it's going to be a bitch to get it to point in 20 knots at all much like my Bristol with it's long keel.

Usually when I'm in 20 knots plus, the waves are large and close (4' - 6') so I have to fall off so far just to get through them that all pointing goes out the window.

Many times I'll use the forecast and sail to the side the wind is rotating to then tack and head home. I'm crossing a 20 mile bay though whereas the OP was talking the last 3 miles.

Plus going by the picture he has an old style long power creating boom with a long keel not a shorter boom for speed with fin keel

And the boat displaced 18,000 lbs! A 30' boat!

Now, that's a cruising boat...............(disp./Len:581)

Viking 30:

VIKING 30 sailboat specifications and details on sailboatdata.com
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Old 19-12-2015, 10:07   #95
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Re: Going hard to wind, main sail trim.

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OP said boat was designed by Lexcen. It's going to be the opposite as an IOR raceboat.

Viking 30: Sailing Boats | Boats Online for Sale | Fibreglass | Western Australia (WA) - Claremont Wa
Oh, okay. Nice. Much better for pointing, etc.
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Old 19-12-2015, 15:01   #96
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Re: Going hard to wind, main sail trim.

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Hi All
Returning to my mooring, the last 3 nm's is always hard to wind in 20 kts. My boat is 30ft, 3.5 tone sloop. She travels well to wind but I wonder if I could be doing better. The set up....., pointing as high as possible, some minor back winding in the top third of the main, traveller hard to windward, main sheet hard on, vang firm, out haul hard, down haul hard, very healed over, ie gunnel awash, and more weather helm than desirable but making 6 knots in the right direction. Occasional uncontrolled rounding up in big gusts. If I ease the main and hold the course it begins to flog. If I dump the traveller, same thing.
Should I drop a few degrees off the wind and add a tack later or stay close hauled? Is there a better way to set the sail when sailing as close as you can go to windward? I have to say I'm pretty happy with 6 knts but the rig is pretty loaded up and the first mate is a little uncomfortable with the heal but getting better all the time. Thanks for your thoughts


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Well an interesting thread. Read through and found lots of interesting technical information. Then went back to your opening post and question.

It would seem to me that in a 30 ft boat you should be putting a reef in your main at possibly 15 but certainly 20Kn. Keep a full Genoa, which is probably your most powerful piece of canvass and which will enable you to point well.

Experiment at 20 kn and try sailing with a full Genoa and 2 reefs in your main. It will not be as exciting but will make little difference to your speed through the water, but with less heel your CMG over the ground will be good.

Once you start to shorten your headsail track car position is very important.

Experiment and find what suits you and your boat best. Remember reefing is not cissy !
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Old 19-12-2015, 16:20   #97
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Re: Going hard to wind, main sail trim.

Quote:
Originally Posted by thomm225 View Post
Now you are playing word games. Okay!

You flatten the mainsail to depower which reduces it's efficiency while give the boat better upwind performance toward the mark.
Yes, thats been my point the entire time- its not word games. The OP wants good performance as he goes to windward. The partly furled genoa will give him poor performance.

I looks like we finally agree.
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Old 20-12-2015, 01:44   #98
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Re: Going hard to wind, main sail trim.

Hey Dockhead, thanks for taking the time to post your excellent piece. I'll have to print that and keep it onboard.
My mainsail is brand new and has made a huge difference to performance both on and off the wind.
Those last few miles home are sailed about 1 mile off an island to windward , so the sea is pretty flat but the wind can be messed up. I do try to sail off a bit in the lulls and pinch up again when I can and as I said, can get to the mooring on a single reach. Now I'll have some new tactics to try. I've never been shy to shorten the main but had so far assumed it would negatively impact my need to point high so I'll be looking forward to experimenting with that. Everyone has contributed so much and it's really appreciated. What a great community we have here.

Here is an older pic of Molly Jo for those interested.Attachment 115342

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Originally Posted by jrbogie View Post



by the way, i've heard many with a masthead rig say that they've removed the baby stay, which works with the backstay adjuster in bending the mast, to get it out of the way for tacks or placing a dingy on deck. one may get away with that with swept back spreaders, for awhile, but otherwise they risk the mast reversing and collapsing in on itself. if your boat has a baby stay it's there for a reason.

You'll notice some added lower shrouds, different to the linked pictures of a Viking 30, that may have been added to minimise any danger of losing the mast once the baby stay was removed. Hope so😀


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Old 20-12-2015, 07:21   #99
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Re: Going hard to wind, main sail trim.

US Sailing has some good tips:

http://www.ussailing.org/wp-content/...%20Shape_2.pdf

http://www.ussailing.org/wp-content/...n%20Trim_2.pdf

United States Sailing Association | Tacking Tips Part I – The Turn
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Old 20-12-2015, 08:14   #100
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Re: Going hard to wind, main sail trim.

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Originally Posted by Dockhead View Post
Amen! What racing boats do, is often not translatable to what we do.

I reef main first, and only in desperate situations do I reef the headsail. I have a blade jib which can be put up instead of the yankee, if there are enough strong bodies on board to do it.

It's better with new sails, but even with them, you can pretty much forget making a lot of progress upwind, once you start to reef the headsail.

Not applicable to the OP, but if you have in-mast furling, like I do, reefing the main has little effect on its shape (someone might say it's just as crappy reefed, as it is not ). The main drawback of the reefed main when hard on the wind is that you lose a disproportionate amount of drive, because the part of the main which is in clean air is the part out closest to the backstay (same reason why roach is so important). So you might roll it in by only 25%, and lose 50% of the drive from the mainsail.

This is not really tragic because by the time you get to wind strong enough to require that, the unreefed headsail is already providing as much power as your boat can use. Let the headsail have its way -- the headsail is the real engine of a cruising rig. My boat actually sails pretty well upwind with the mainsail completely put away.
We are in perfect accord on this, as in your longer piece directly preceding it, which was, by the way, excellent.
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Old 20-12-2015, 12:04   #101
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Re: Going hard to wind, main sail trim.

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I agree with previous posters, that a reef would be a good idea. She just sounds overpressed. But also I am slightly concerned about the "traveller hard to windward, mainsheet hard on" idea… if the main is being brought in beyond the centreline of the vessel you are likely causing it to be inefficient, and increasing leeway and drag in the keel. The whole approach seems a little "everything hard cranked on". The idea is to get the ideal mainsail shape… not just crank everything down and hope for the


best (I really don't mean to say that this is what you are doing but everything hard on without thinking about sail shape is a bit like that), and if your traveller is fairly wide, the main may be being effectively

to windward, which will be braking


her, to some extent.
Best comment: looking at the shape of the sail. The shape.


It's so daring to sail all heeled over and taking the wind on your face.

In the North Sea with 4- 6 foot swells
I found I can surpass my hull speed heeled at 30 degrees and sailing on full waterline. But, in the end it's the shape of the sail even if you're tacking off 20 degrees, the best airfoil will pull the boat beyond your hull speed and get you there faster. That's the seamanship via a vis the physics.

Big argument amongst sailors, this. 😇
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Old 20-12-2015, 15:44   #102
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Re: Going hard to wind, main sail trim.

We have of course ignored that fact that the OP is talking about the last 3nm into his berth. At 6kts this is the last 30mins of the day and at cruising revs I can make 6kts on the iron main. As most harbours have some kind of speed limit (ours is 5kts then 3kts in the marina itself) one does have to wonder why not drop the canvas and just motor the last wee bit?

Sure it is more challenging to come in under sail but the vast majority of harbours and marinas really frown on that unless you radio in and tell them you have lost the propulsion, in which case they'll come out and "rescue" you with the dinghy.

Out at sea I can fully agree that getting the sail set right makes a HUGE difference to performance and that is something we can all learn about regardless of if we race or just cruise but really in the last half hour of the day does it matter?

K
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Old 20-12-2015, 17:15   #103
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Re: Going hard to wind, main sail trim.

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Originally Posted by kas_1611 View Post
We have of course ignored that fact that the OP is talking about the last 3nm into his berth. At 6kts this is the last 30mins of the day and at cruising revs I can make 6kts on the iron main. As most harbours have some kind of speed limit (ours is 5kts then 3kts in the marina itself) one does have to wonder why not drop the canvas and just motor the last wee bit?

Sure it is more challenging to come in under sail but the vast majority of harbours and marinas really frown on that unless you radio in and tell them you have lost the propulsion, in which case they'll come out and "rescue" you with the dinghy.

Out at sea I can fully agree that getting the sail set right makes a HUGE difference to performance and that is something we can all learn about regardless of if we race or just cruise but really in the last half hour of the day does it matter?

K
Not sure but I think the OP's point was that the particular area of water (near his destination) typically creates the situation. It could happen far away or nearby and he's wanting to learn how best to deal with it.
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Old 21-12-2015, 00:08   #104
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Re: Going hard to wind, main sail trim.

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Not sure but I think the OP's point was that the particular area of water (near his destination) typically creates the situation. It could happen far away or nearby and he's wanting to learn how best to deal with it.
Fair point, just offering up another solution to the problem

Must admit I have learnt a bit myself from this thread which is the main reason we all come here

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Old 23-12-2015, 19:14   #105
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Re: Going hard to wind, main sail trim.

Something else that I dont think has been touched on yet is to move your genoa cars aft in stronger winds. It will flatten the foot of the sail and open the upper leach. This will also help reduce the healing moment of the boat.
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