Heeling/Need help

Thread starter #1
Hi all. I'm a novice laser sailor and i'm trying to understand more reading 'A Laser training manual' by Anderson. In mainsheet adjustment section it is stated that
"As the sailing angle is reduced, and the boom is brought forward to sail higher into the wind, the total aerodynamic force is
directed more laterally. Consequently, the relative size of the driving force decreases and the heeling force increases"
but when i sail and heel so much for me i always harden up to reduce heeling and it seems on the contrary stated in the book.
Someone can explain me better?
thanks
 

LaLi

Well-Known Member
#2
That passage sounds quite misleadingly written. "Bringing the boom forward" makes no sense.

I'm not familiar with the book, but it looks like it's available as a free PDF, so I'll see if the context makes it any clearer.

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LaLi

Well-Known Member
#3
As I expected, the quote is about comparing the relative forces acting on the sail reaching vs. upwind. Just change that one sentence to "...and the boom is sheeted in..." and it makes sense again.

What you're thinking about is feathering, which is a much smaller course change to depower when already sailing upwind. It's actually defined in the book just before that passage on page 27, and again on page 48.

Interesting book, by the way. Lots of outdated content, but mostly useful reading nonetheless. Please ask more questions if you have any!

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#4
Hi all. I'm a novice laser sailor and i'm trying to understand more reading 'A Laser training manual' by Anderson. In mainsheet adjustment section it is stated that
"As the sailing angle is reduced, and the boom is brought forward to sail higher into the wind, the total aerodynamic force is
directed more laterally. Consequently, the relative size of the driving force decreases and the heeling force increases"
but when i sail and heel so much for me i always harden up to reduce heeling and it seems on the contrary stated in the book.
Someone can explain me better?
thanks
Einstein reportedly said, “If you can’t explain it to your Grandmother, you don’t understand it.” Author’s Grandmother must be smarter than me.
 
Thread starter #5
As I expected, the quote is about comparing the relative forces acting on the sail reaching vs. upwind. Just change that one sentence to "...and the boom is sheeted in..." and it makes sense again.

What you're thinking about is feathering, which is a much smaller course change to depower when already sailing upwind. It's actually defined in the book just before that passage on page 27, and again on page 48.

Interesting book, by the way. Lots of outdated content, but mostly useful reading nonetheless. Please ask more questions if you have any!

_
Thanks Lali. Now understand what it means. You are right and i think it is different sailing upwind and upwind in a gusts. I had a bad idea that on beam reach heeling force was more than sailing on close hauled. By the way i have another question.
Is it correct to say i should sail block to block only on close hauled and ease the mainsheet on lower course?
thanks
 

LaLi

Well-Known Member
#6
"Block-to-block" means that your sheet has run out of range of adjustment, and you've reached (or are close to) minimum twist and maximum mast bend. So yes, you should do it only when sailing a close-hauled course in conditions when feathering is enough for depowering. If you want to sail a lower course, you ease both the sheet and the vang (and cunningham), but if you have to do that for depowering, then you let out just the sheet in gusts and keep everything else tight.

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#8
Hi all. I'm a novice laser sailor and i'm trying to understand more reading 'A Laser training manual' by Anderson. In mainsheet adjustment section it is stated that
"As the sailing angle is reduced, and the boom is brought forward to sail higher into the wind, the total aerodynamic force is
directed more laterally. Consequently, the relative size of the driving force decreases and the heeling force increases"
but when i sail and heel so much for me i always harden up to reduce heeling and it seems on the contrary stated in the book.
Someone can explain me better?
thanks
I've read this and the replies a couple of times now over the past week, and I'm still trying to find a way to explain it simply enough so that my Grandmother would understand.

I think that the original text makes sense as-is.

Imagine that you are on a close reach, and you quickly steer up closer to the wind (without trimming the main). What happens is that your bow typically comes up out of the water (sometimes a little, sometimes ALOT) and your boat heels over -until your sail de-powers and flaps around abit.

Essentially when you steer up quickly, your hull, foils, boom, lower mast etc. are brought forward and higher into the wind. The pressure in the sail wants to stay where it is? so the force changes from flowing over the sail (as when properly trimmed) to a more lateral force. Boat moves up, force in the sail wants to stay where it is, boat heels over as a result. Hence we have to hike our butts off when hardening up and sheeting in at the same time.

I could probably explain this better with a drawing lol.

I think what I am trying to say is, "When you steer up AND trim the mainsail to match the course and stay fully powered, your boat will naturally heel over."

On the contrary, "When you steer up WITHOUT trimming the mainsail, you are causing it to luff and de-power i.e. feathering."

It's been a long week, apologies if this makes no sense at all.


PS: the Marit Bouwmeester videos look amazing.
 

thieuster

Active Member
#9
Not Marit Bouwmeester, but another Dutch sailor: Niels Broekhuizen. He posts short videos shot by his trainer/training mates on Instagram. The water is the North Sea, just for the coast of Scheveningen (unpronounceable when you're not Dutch - hence the 'slang name' Schiffa Bay).

Take a good look at Niels' wave-attack and how he works with his body, his sheet (and boom) and his joystick. The first vid is down wind, the other up wind. Look at the way he controls the sheet!

I am not very gifted when it comes to copy/ pasting this sort of things...

http://instagr.am/p/BoE4V2ainHQ/
http://instagr.am/p/BnbwjZ4CZMK/
 
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LaLi

Well-Known Member
#10
If you want to sail a lower course, you ease both the sheet and the vang (and cunningham), but if you have to do that for depowering, then you let out just the sheet in gusts and keep everything else tight.
That's what Niels is doing in the latter clip. Looks nice.

_
 

thieuster

Active Member
#11
What's important as well: the quality of the traveller and how much tension the traveller has. When the traveller is too loose, the sheet-blocks on the deck tend to go inwards, to the middle of the boat. That compromises the position of the boom/sail as well!

Look at Niels' latter video. Do you see that the sheet blocks stay on the far left side of the boat, near the gunwale (is that the term in English?)

Modern material travellers are e.g. the DM20 Dyneema + polyester line. Not cheap, but pretty good. I think that the original Dyneema line that comes with the XD kit, is not worth the money. The centre cleat is unable to 'hold' the slippery Dyneema line tensioned. Therefore the DM20 with the polyester fibres works better with the cleat.

Menno
 

LaLi

Well-Known Member
#12
Actually, when the boom is constantly outside the gunwale and the vang takes practically all of the vertical load, traveller tension isn't all-important anymore. It's rather in light-to-medium conditions, when the traveller blocks want to creep towards the centreline, when you want to have the traveller as tight as possible.

Any Dyneema- or Vectran-core rope is good enough for the Laser traveller. DM20 is overkill, it's developed for applications that are heavily loaded for days on end. Slipping in the cleat is whole another thing, but I believe most people with 5 mm single-braid Dyneema (or Vectran) don't have a problem with it.

_
 

thieuster

Active Member
#13
5mm has to do with it, I suppose. DM20 is a little larger/thicker and holds better in the cleat. Perhaps it is over-engineered for a traveller-purpose but it works. And looking at the boats in Kiel during the U19 WC, most sailors like it.
(On the other hand: I am a big fan of UK's Max Hunt's Southeastsailboats - Ropes for Boats. He has come up with lightweight, interesting & spliced control lines for Lasers).
 

LaLi

Well-Known Member
#14
Well, DM20 is a material, a grade of Dyneema with the least creep (which is largely irrelevant in dinghies), not a brand name of any rope. Southeast Sailboats only sells single-braid SK78 Dyneema for travellers; Rooster's offer is indeed DM20, 100 % actually. Looks like the latter used to sell both a DM20/polyester mix as well as a Vectran/polyester alternative, though, as Steve demonstrates in a video a few years back:


Is that what you're taking about?

(Getting off topic, but ropes are always fun :D )

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thieuster

Active Member
#15
Yup, that's what I'm referring to. Steve's products has reached our shores as well and at least two suppliers here sell it; one being the official Dutch dealer for LP and the other a marine chandlery that's also sponsor of the Dutch Laser crew - hence the connection to DM20.

Apart from DM20 being a material, I have no idea how it to call otherwise. We're always referring to "DM20".

Sailcenter.nl DM20
 

LaLi

Well-Known Member
#16
The rope in question seems to be 6 mm "50/50" by English Braids. It's nowhere to be seen on the EB website, though, and isn't available even at Rooster, although it probably was specially made for them.

By the way, my own traveller is a 5 mm all-Vectran one from Marlow; it sits pretty deep in the cleat but hasn't slipped yet :cool:

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