Tuesday, 2 March 2010

LTW Readers Q&A | 036; Sheeting in a Laser

Since there were so many unanswered Q&A’s in my mailbox, I decided to spend a couple of hours Saturday to catch up. I apologies to all for taking so long to get to this. I’ll schedule posting as many as I can this & next week.

This RRS Question one is from Bence from Hungary about sheeting in a Laser. He writes:

Dear Jos,
I have been reading your rrsstudy-blog for more than a year and I find it really interesting. Just keep up the good work!
I live in Hungary and I'm sailing in Laser Radial now. Besides racing I also organize races and sometimes work as a national jury. We had a regatta last month here in Hungary and there was an argument between the judges, coaches and competitors about controlling the mainsheet in the laser class.
According to the cited rule's last sentence you may control the sheet directly from below the forward boom block.
Is it allowed to use it in such a way for adjusting the sail to a slight change of wind direction, either in a beat on a wave or in a reach?
When doing so, could it be regarded as a pump or not? If there are no surfing or planning conditions, I guess it is a pump and so not allowed.
To facilitate tacking and gybing it can be controlled from any part of it (also aft the forward boom block) - that's clear.
Please try to answer if you can, or if not, could you offer me a laser-expert jury to contact? We also tried to ask it from the International Laser Class Association, but unfortunately we still didn't get any answer...
Kind regards, Bence Böröcz HUN
My answer to Bence is after the jump.

The rule governing the way we can adjust the sails to propel our boat is rule 42.

That is the same in a Laser as in a Elliot 6 or Star. There is (with one exception) NO specific way or place or holding point described in the RRS how to do this.

You can push your boom out if you want, or a crewmember may hold the gib for backing at the sheeting corner. If you want to push the boom up to open the leech, please go ahead. You may even hold the boom – if you have the strength.

The one exception is when you want to initiate surfing! Then rule 42.3(c) specifically states you MUST do so by pulling a sheet or guy. The way most PC/Jury panels interpret this, is that as long as your are touching the sheet with your hand – be it directly on the block – you are complying with this rule.

Next are the Class rules. They also can regulate (change) how the sails are to be used. (It can also be done in the SI’s – but I’ll save that for another time)

In the Laser Class there’s a specific CLASS-rule involved in how you can adjust your sails. Bence already referred to this in his mail:
(c) Mainsheet – also see Rules 3(a) & 3(b)
i. The mainsheet shall be a single line, and be attached to the becket of the aft boom block, and then passed through the traveller block, the aft boom block, boom eye strap, forward boom block and the mainsheet block. After the mainsheet block it shall be knotted. The mainsheet shall not be controlled aft of the forward boom block except to facilitate a tack or gybe.
In answer to your question I would allow adjusting the sails in a Laser (Radial or Standard) as long as you touch the forward boom block. Thereby complying with the class rule of never controlling the mainsheet aft of that block.

There are lots of Laser sailors active in the blogosphere – more so then other classes it seems – perhaps they can shed some light on this?

Next time in LTW Readers Q&A; Rule 14 after contact.




  1. There are rules and then there is what is sensible to do in any given boat...

    Yes, the class rules allow trimming the mainsheet using the part of the sheet that runs from below the forward boom block to the mainsheet block on the deck. There is no requirement to "touch the forward boom block" as Jos mentions. Not sure why he said that?

    Some Laser sailors like to trim the sail this way in lighter airs when sailing on a reach or run. It does give you a better feel for the pressure in the sail.

    Some Laser sailors like to trim the sail this way in planing or surfing conditions because they think it's easier to pump the sail effectively to initiate planing or surfing.

    If it's not planing or surfing conditions then you can still hold the sheet there, but clearly it would violate Rule 42 if you pumped the sail. But a trim of the sheet to respond to a change in apparent wind is not necessarily a pump. So, I think Bence is wrong in saying that this is always a pump in these conditions.

    Yes you can hold the sheet aft of the forward boom block to facilitate a tack or a gybe. One example of this is on a light air run-to-run gybe when some Laser sailors like to reach back and grab the double length of sheet near the traveler and pull it across the boat.

    As far as I know hardly any Laser sailors control the sheet from directly below the forward boom block when beating, though it is allowed. I suppose you could do it in very light air when the sheet isn't trimmed block-to-block. And if you experienced a lift you would ease the sheet before heading up, or if the wind speed increased you would trim in a bit. Both of such actions would be legal in my opinion. But if you were repeatedly tugging the sheet here in the absence of any change in wind direction or speed, it would be pumping and a Rule 42 violation.

  2. Thanks Tillerman.
    I suspected you might have a thought about this.
    As for my 'touching the block' advice... that way you can always 'prove' you never pull the sheet aft of that block. I meant it as the most aft position possible.

  3. As usual I applaud Tillerman's homespun wisdom. (do Laser Class rules permit sails to be made out of homespun wisdom?)

    Tillerman said "But a trim of the sheet to respond to a change in apparent wind is not necessarily a pump."

    A trim of the sheet to respond to a change in wind (or waves) is NEVER a pump.

    A pump is a single pull on a sail that is unrelated to wind or waves. (ISAF Rule 42 Interpretations Definitions).

    The critical issue here is how the RRS and the Laser Class Rules (CR) deal with:

    * a pull on the sail made by a pull on the sheet, and

    * a pull on the sail made other than by a pull on the sheet, for example by pulling on the boom directly.

    Rule 42 does not distinguish between whether a pull on a sail is through the sheet or in some other way EXCEPT that the permitted pull on a sail to initiate surfing or planing under rule 42.3(c) must be a pull [on] the sheet [or guy].

    Any trimming or other control or adjustment of a sail, other than the single permitted pull to initiate surfing or planing, may be done directly to the boom, or any other part of the sail or rig.

    The Laser CR 3(c) addresses how the mainsheet shall be controlled.

    Like rule 42, it does not impose any restrictions on whether or how a pull on the sail may be applied. It merely says that IF a pull on the sail is applied through the [main]sheet, it must be applied not aft of the forward boom block.

    Thus, under the Laser CR, in your permitted pull to initiate surfing or planing, you cannot take both parts of the sheet from behind and ahead of the forward boom block in your hand and use it as a handle to pull the boom and sail directly.

    In my opinion, if you are controlling the mainsheet, just keeping contact with the forward boom block is not enough to comply with the requirements of Laser CR 3(c)if you are exerting any sort of control of the sheet aft of the block: you may only control (touch?) the sheet forward of the block. BUT, except for your one permitted pull to initiate surfing or planing, you can pull the boom (and thereby the sail) directly by any part, and may pull the forward boom block directly if you wish.


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