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**Peerie Maa** · 01-29-2022, 05:42 PM

Re: Newbie looking for some guidance please...sail plan

It looks to be a bit far aft. It should be about 1' 10" ahead of the centre of area of the sail.

**Todd Bradshaw** · 01-29-2022, 06:32 PM

Re: Newbie looking for some guidance please...sail plan

I'd like to see the intersection of the mast and yard moved forward on the yard a bit. Most likely, removing some or all of the mast rake would be the easiest way to do it. Lugsails don't perform well without a lot of luff tension. Since they are not attached along their luffs to a mast, the luff tension has to be provided in other ways. If not, the luff will tend to constantly wobble back and forth, trying to find a stable position. The yard needs to be attached to the halyard in a spot which will make the yard seriously "tail heavy". This creates a firm upward pull from the throat corner and the butt end of the yard. This then pulls against the downward pull on the sail's tack corner by the downhaul. Without this two-part luff tensioning scenario going on, lugs don't work well.

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**Autonomous** · 01-29-2022, 07:28 PM

Re: Newbie looking for some guidance please...sail plan

I love this place. Two qualified expert replies in an hour!

**Benny** · 01-30-2022, 05:18 PM

Re: Newbie looking for some guidance please...sail plan

Thank you Peerie Maa and Todd for your thoughts and comments

Not sure I can get the dagger that forward without issue, maybe I misunderstand... I have moved it forwards about 1ft, any further and it's way off the beam which I believe is a further complicating factor?

I have reduced the mast rake and noted your comment Todd around halyard fixing point thank you

Also been reading with interest a couple of threads about the build and sailplan of several Argie 15's and birdsmouth spars...what a great resource this forum is. THANK YOU

Benny

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**Todd Bradshaw** · 01-30-2022, 06:55 PM

Re: Newbie looking for some guidance please...sail plan

Given the option, I'd rather see the tack corner brought back to the mast, not out ahead of it, and I would get rid of nearly all of the excess halyard between the masthead and the yard. You also most likely may have a problem with your mainsheet angle. On a boomless sail the sheet angle is really critical as it needs to create a balance between the foot tension and the leech tension, with the leech tension generally taking the priority. Too little leech tension creates a constantly flapping leech. Lugs can be a bit different from other sails, but usually we look for the sheet angle to run between the mainsheet cleat or fairlead and a spot mid-luff or fairly close to it, rather than bisecting the clue. In many cases, the addition of a boom simply makes a standing lug much easier to operate as it pretty much eliminates sheet angle problems.

Perhaps we can get some help from one of the designers on the forum, but I was always taught that most single-sail dinghies should probably have lead (as in leed) of around 10% of their waterline length, with the sailplan's Center of Effort being that far ahead of the hull's center of lateral plane, the biggest part of which will be the centerboard's location. In that case, I would not move the board forward. For some small, narrow boats, like canoes, we generally start with the leeboards directly under the sail's CE and adjust as needed during the sea trials. A wider dinghy when heeled over wants to carve a turn to weather (upwind - weather helm). By sticking the sail's Center of Effort slightly ahead of the board and CLP the wind pressure helps to reduce the weather helm somewhat without having to steer more downwind with the rudder and cause more drag.

**Peerie Maa** · 01-31-2022, 05:55 AM

Re: Newbie looking for some guidance please...sail plan

My bad. Serious typo. My apologies.
The sail CoE should be forward of the CB, not the other way round, I would go with Todd's 10%, 14". It will probably be easier to alter the rake of the mast rather than moving the CB case.

**Benny** · 01-31-2022, 04:17 PM

Re: Newbie looking for some guidance please...sail plan

Thanks again, your further input and clarifications is truly appreciated!

I'd better get on with the build.... cheers

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**Ben Fuller** · 01-31-2022, 04:40 PM

Re: Newbie looking for some guidance please...sail plan

You may want to look at the structural issues. I don't know your design. There is a lot of torque between the mast partners, the step, the dagger board and you sitting to windward. The DB trunk will need to be braced to the sides.

**Benny** · 05-31-2023, 06:57 AM

Re: Newbie looking for some guidance please...sail plan

Ben Fuller I do apologise I missed your reply...or did not reply at least. Thank you for the input ��

The build progresses..photo below of its current state

Thinking about rigging...I plan on a super simple mainsheet set up like Roger Barns uses on his Ilur, switching the sheet from side to side as necessary and was going to make a timber hook type 'thing' to take the mainsheet to first, from the clew, attached to the top of the gunnel but I think that maybe quite obtrusive.

I could fit fairleads which maybe less obtrusive or make up a rope traveller arrangement which may allow some adjustment on the foot and leech tension...

Any thoughts and experience on that most welcomed!

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**WI-Tom** · 05-31-2023, 10:38 PM

Re: Newbie looking for some guidance please...sail plan

The sail is boomless, correct?

In that case, it looks to me as if your sheeting point as drawn is a little too far forward--I think the sheet should more or less follow the line that bisects the sail from throat to clew. I don't know how much your slight deviation will matter, but sheeting angles are very important with a boomless sail. In general, it works best to sheet the mainsail as far aft, and as far outboard, as possible.

The Roger Barnes-style sheeting, hooking the sheet on the leeward gunwale at each tack or gybe works fine once you get used to it. That's what I do with my boat, which has a boomless standing lugsail.

As far as a rope traveler over the tiller, that might not work all that well, depending on your tiller height. If your tiller is high enough that your traveler takes on an inverted V shape to get over the tiller, then the mainsheet block/ring often gets caught in the apex of that inverted V, and cannot slide far enough outboard to maintain proper sheeting angles. I tried this on my boat as well, and found that it doesn't work well because of that issue.

Hope this helps!

Tom

**WI-Tom** · 05-31-2023, 10:40 PM

Re: Newbie looking for some guidance please...sail plan

Also, if you do go with the "hook the sheet on the gunwale" rigging as in the French misainier rig, I find it's better to use a rigid ring (metal) for the sheet--this can be more easily hooked over your gunwale cleat when working one-handed. A rope grommet tends to collapse a bit and can be trickier to hook on the cleat.

Tom

**Benny** · 06-03-2023, 04:33 PM

Re: Newbie looking for some guidance please...sail plan

Tom many thanks for your thoughts. You helped me make up my mind to stick with my original plans and not try a traveller type arrangement.
Noting the point about the sheet angle I reread Todd Bradshaws posts and realise I had got it all confuddled, thanks again, I'll fix the cleats I'm making right back aft

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Newbie looking for some guidance please...sail plan

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