Makes more sense if you meant today weather helm, methinks. If the tiller falls off to lee, the bow should point up into the wind, no? (...while you yell, "lee ho!" in your saltiest pirate-ese)
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OH OH you're right you're right. I'm sorry, hazy Sunday morning.
It's when the boat is flat, the tiller can swing either way, sometimes making lee helm. Not as a solid theory anymore, when I think about. But I still haven't had any lee helm problems. This probably doesn't apply to anyone who has a tiller cut to the planned length. Excuse my drivel.
Christophe
I have slight weather helm on reaches and of course runs, so that is not my problem, but there's just some fine tuning to get a little weather helm on the beats, as otherwise pointing ability goes to custard with lee helm... There's only cm required in the adjustment. A lot of racing boats can go from lee helm to weather helm by moving the mast back only a few cm in the step, or just with rake. We have to move the sail back by moving the halyard attachment forward, and by making a corresponding adjustment to the downhaul position as well.
Your February just got booked all up.
A little bit of a drive, a little bit of a ferry boat ride, and some adventure!
My boat is mothballed for the winter, all of us in the Northern Hemisphere are counting on you!
Tawe Nunnugah - A Raid in Paradise?
Hi Christophe,
That trip would be quite awesome to do for sure, and one that I really would like to do one day, when we retire to Tasmania :U.
I am planning on being there for the Wooden Boat Festival in Hobart and we will be staying in Kettering, just south of Hobart on the D’Entrecasteux Channel. Lovely spot it is too. The thing is we always fly there due to the tyranny of the distance involved. It is a huge haul by car with a boat on trailer from Maitland NSW down to Melbourne, catching the Spirit of Tasmania Ferry across Bass Strait to Devonport, and then the trip down south across Tasmania to Hobart.
Sadly the Spirit of Tasmania no longer sails from Sydney, otherwise the trip with the GIS would have been very feasible for me. I’d only have to install rowlocks and make some oars!
The D’Entrecasteux Channel can be a rough place for dinghies. I’ve been across to Bruny Island on the ferry from Kettering in some pretty rough weather, and the waves get pretty big. It can be a far cry from Andrew Denman’s (Denman Marine) idyllic sailing videos of Tirriks and Caledonia Yawls! Storm Bay is not far away (I wonder how it got that name?). Still, with an expert crew and reasonable weather, the GIS would, I think, street the pack.
As I mentioned, Kim and I are planning to be there in February for the Wooden Boat Festival. There is also a very real possibility that I may also be doing a trip up the D’Entrecasteux Channel into Hobart in an Oughtred boat. I can’t say too much yet because it’s still not 100% certain this boat will be available or that my assistance will be needed. However, if it all works out I should be like a pig in mud. :U
Well ... I will probably catch up with you at Hobart!
MIK
Cool!
Will you be taking Beth?
No ... I will be bludging a chain of lifts to get there.
Also will be coming down from Sydney and probably going back to Brisbane after.
MIK
Went sailing yesterday on Grahamstown Dam, near Newcastle. The forecast of 10 knots in the morning freshening at around midday to 20 knots (Windfinder and Weatherzone) didn't happen.
What did we get? Well, 5 knot puffs from every point on the compass is what we got, in between nothing at all....0 knots for much of the day!
Worst of all, I gave it a rinsing twice! Once coming in to shore and the other when the wind switched 180 degrees on me while I was sitting on the rail, port tack, close hauled. As quick as I could I was over to the other side and staring face down at the centreboard trying to get my weight over as far as possible. I recovered it without going over completely, but the gunwale went under and I shipped about 2" of water.
When coming ashore to adjust my yard attachment (see below), I was in was in 30cm of water, the breeze (no more than 2 knots behind me, centreboard had just been removed and maybe just 20cm of rudder. I rounded up slightly but was too tardy in jumping out and she rolled over to windward. Very embarrassing! The good thing was that once I'd bailed it to no more than 5cm, the rest was removed by tipping it over.
The lee helm issue:
Well, I'm flummoxed. I moved the attachment point of the halyard, the loop on the yard, forward to the 40% mark, and moved the downhaul forward to about 30 cm from the front of the boom to keep the sail parallel with the mast. This was marginally better, but I still had some lee helm when close hauled. I then moved the yard halyard lashing further forward to about 35% (I say about because I have no marks in front of 40%, so will confirm this). Needless to say, the vang effect of the downhaul is now marginal, and my boom is kicking up in the air a bit more than I'd like.
In the end, the flaky breeze wasn't really conducive to proper tuning. I could probably try freeing off the tension along the yard a little more, but at this stage I'm at a point where raking the mast is probably the only option left.
I'm confused too. You could try the opti trick of adjusting the lashing tension along the yard to flatten or make the top of the sail more or less deep and see what that does. They use individual ties and allow the sail to take a different curve to the yard (or cable ties).
On an observable basis, what do you think the bend is compared to the original? Start with reproducing that amount of curve using the cable ties. That will tell you/us whether it is something to do with the draft or some other dynamic from the stiffer yard.
MIK
Attachment 151507
Hi MIK
As you can see, I do use cable ties, which do make the adjustment easy as they slide up and down the yard nicely. This end on pic which greatly exaggerates the bend of the yard shows the maximum bend I'm getting with the downhaul in as hard as possible. This maximum bend is replicating the curve in the sail exactly, which is pretty much what I was after with the new yard. Basically its stiff. This allows more fullness when the wind is light and there is less tension on the downhaul, and perfectly flat when the breeze is up. Pretty ideal I would think MIK? The tube is 38mm diameter with 3mm wall thickness and weighs in at a hefty 3.2kg.
The tension here is with about 2" of slack from throat to peak. Any more than this, even slight and the sail gets crinkles, like in this shot:
Attachment 151509
I also played around with the tension of the foot, hoping that more power from a big draft would help, but it didn't much.
This morning I checked the mast partner and mast step measurements from the #1 bulkhead to the front of the step and front of the partner, and they are spot on to the plans, ie. 83mm and 80mm respectively. I woke up last night with the thought I had stuffed this up!
EDIT: I've just realised I misunderstood what you meant by "They use individual ties and allow the sail to take a different curve to the yard (or cable ties)." In other words, adjust the tension of ties to allow the sail depth to be independent of the curve of the yard!
Exactly ... If the sail is given something like the curve it has at the top on the wooden spar then it will be interesting to see if the handling goes back to the original. Another thought ... with the OzRacer/OZ PDRacer - the mast bend brings the rig into balance. i don't think it will be so effective with the lug because of the shortness of the spar. But just trying to find out the reason. MIK
Howdy. I am thinking (dangerous) that re raking the mast might be about the hardest choice. I would persevere with some of the stuff above - altering the edge curve of the sail with cable ties etc. If it becomes important to do some physical changes - it might be easer to alter the centreboard rake by cutting the back of the board away inside the case. I think you would have to do a mock up with the actual clearance you have in your case to see how far you could get it to move. MIK
OK that makes sense as it has the effect of moving the centre of effort forward.
I've just had a thought about my rudder. When by brother was here and we were doing all that sailing in heavy wind, the shock cord around the rudder case wasn't strong enough to stop the rudder being dragged aft and making the boat hard to steer, so we were sailing with it in the 3/4 down position to reduce the drag which was pulling the rudder out of the cassette. Perhaps this was enough to induce weather helm? Since beefing up the shock cord to 10mm, I've been sailing with it in the full down position. Next time I could try raising my rudder a bit and see what happens.
But I'll also fiddle with the ties on the yard. Leaving the end ones tight and slackening the middle ones will induce more shape, which may be just enough.
Howdy ... less rudder just means more angle to get the same amount of side force. It doesn't really change the geometric set up of the force ... still has to be the same.
MIK