Rounding up (weather helm)

[bastonjock]

i was out yesterday and had the wind drop quite a bit so i ended up sailing downwind,the sea was just pushing me around,there was very little forward motion under sail,the best i could get was 2.3knots,i did manage to briefly have the boat gull winged but the wind kept moving around so i furled the jib and ended up snaking all over the place with a following sea,id like to try it with more wind,but does the handle so badly downwind?

when i first went out it was blowing strongly and i was managing 5-6knots at about 50 deg into the wind,there was a 4ft swell with a choppy top hitting me on the beam,i did give myself some concern when i let the main sail out,it seemed to catch the wind better and with a 4ft swell,the boat healed over quite far(i can still hear the stuff flying about in the galley),i reefed her at this point

i spent the weekend single handed,this was my first attempt,ill need to inproove my rigging a bit,more mods required,almost lost one of my gas tanks as it flew out of the hole

[RickJ]

Re. wind speed - it's quite possible I'm underestimating. This is the readout on my ST40 wind indicator which I installed over the winter. It does have a fault with direction indication and I'm waiting a replacement display. I've assumed speed indication is OK, mainly because it seems to be consistent, but maybe that's wrong too. The numbers I was quoting might need a correction factor - feel free to apply your own.

Mast rake: even though the forestay turnbuckle is fully in, I still have fine adjustment on the upper shrouds. The mast could come further forward with a shorter forestay. The backstay already has an adjuster.

Leon - yes I did have the ballast in.
I was sailing with 1-reefed main and full jib as close-hauled as I could get, which was within 45° to apparent according to the windex.

Part of the problem could be that I probably need new sails. There's a lot of sag in these and the main won't really flatten enough, even with vang and backstay pulled hard.

It seems to me though that there are two separate effects here. I would expect rig and sail trim issues to create a progressive tendency to steer to weather, which I guess I have anyway. However, there is a sudden, very sharp rounding up that occurs at the extreme, which seems much more related to heel angle. This is what reminded me of dinghy behaviour.

Maybe Moe is on the money in that it's the degree of drive occuring toward the top of the mast which is way outboard at this point. Better sails should help deal with that. It's also exacerbated by the fact that you loose a lot of steering at this stage, with the windward rudder largely out of the water and the leeward one a long way from optimal vertical angle. Hence my comment about rudders. It wouldn't cure the effect, but might it make it more manageable?

Cheers, Rick

[RickJ]

Matt - I haven't found mine particularly easy to sail downwind either. In fact directly downwind is almost impossible. The jib won't fly gull-wing (I suppose a whisker pole might help - if I had one ), and main alone doesn't generate enough power.

I've found I really need to tack downwind, at about the same angle as upwind, in order to get the jib to work. Whether this is actually any quicker over the ground than running straight downwind with just the main I haven't worked out. More pleasant to sail though.

I've often wondered whether the cruising chute is worth the money

Cheers, Rick

[Moe]

Rick, what you're describing at 30º is just like our C-18. Doesn't matter what point of sail you're on, if it gets that far over, it's rounding up hard and there isn't a thing you can do about it. You can barely save it at 25º without stalling the rudder. Much finesse required. Of course, you have to be overcanvassed, oversheeted, and working hard to try to get it that far over. I never felt anything near that with the 26X, which was pretty easy to get over that far. That's why I doubted it was the hull, especially with all of that hull in the water aft.

I didn't like sailing dead downwind with the 26X. It was hot and excruciatingly slow, without much rudder authority. With the heavily aft swept spreaders, I couldn't get the mainsail out far enough... only about good enough for a broad reach, and as a result, I constantly worried about an accidental gybe with the big mainsail. It was tough to wing on wing even the working jib without a pole. So I stuck to gybing downwind, or gave up and motored under sail if I didn't have maneuvering room.

--
Moe

[/list]

[bastonjock]

moe did you try a spinnaker for sailing downwind?,your post for me hit the nail on the head, i could not get the mainsail out far enough

[Scott]

10 kts wind shouldn't require a reef and shouldn't produce more than about 10-15 degrees heel upwind with full main & jib and roughly 20 degrees with full main and genoa. Most likely your sails were oversheeted. Were you using jib or genoa? What point of sail? Are you sure the wind wasn't higher than 10 kts? Reducing mast rake will help a lot, but proper sail trim is the first remedy. Not to sound like a smartass, but this can happen to any of us. Did you fill the ballast tank?

I agree with this.

A good practice for initial sheeting angle is to find the tack you want and let the sails out until they begin to luff. At this time sheet in only enough to fill them, (stop the luff) do you still get the same amount of heel (a side benefit may be an increase in speed. (this works on a beat, not on a run) Over sheeting can have the same effect as flood a car out .

[Moe]

moe did you try a spinnaker for sailing downwind?,your post for me hit the nail on the head, i could not get the mainsail out far enough

No, I never did try a spinnaker.

[delevi]

Rick,

You may be correct in your assessment of blown out sails. I blew out my stock sails, which clearly weren't designed for SF Bay. I had excessive heel and uncontralable roundups, though not at 10 kts wind. Quality new sails made an unbelievable difference. IDA rudders helped as well, as did the weighted keel. Certainly no need for all these mods if you don't sail in high winds frequently. I'm guessing it's one or more of these: blown out sails, oversheeting, possibly faulty instrument readout on wind velocity, though I'm sure you would know if you were sailing around 20 kts vs. 10. If you were sailing with a genoa, it may explain some of this. The 150 genny overpowers the boat above 12 kts on a beat. If your sails are blown out, it might happen at slower wind velocity. A very common symptyom is rapid flutter along the leech.

Leon

[delevi]

Rick,

How do you like your ST40 wind instrument. I just ordered one. Do you find the wind angle to be accurate with the rotavecta transducer? Where did you mount it? I'm thinking about mounting the transducer on the arch off the transom (mast support unit for trailering.) I will probably mount the display on the port bulkead.

[RickJ]

Leon

I think sails have to got to be the main culprit. The main is actually the one for a Mac25 (says so on it!). I gather it was specified by the original owner, which may be because it comes with 3 reef points not one. There is a lot of sag at the luff which probably means that when hauled in enough to stop the luff luffing, the sail in total is over-sheeted.

More expense

How do you like your ST40 wind instrument. I just ordered one. Do you find the wind angle to be accurate with the rotavecta transducer? Where did you mount it? I'm thinking about mounting the transducer on the arch off the transom (mast support unit for trailering.) I will probably mount the display on the port bulkead.

Well so far my experience with the ST40 isn't too good, because I think I got sent a rogue item. To start with some of the mounting parts for the transducer were missing so I had to get those sent on. Now it turns out that I can't calibrate the direction mode. The linearisation (where you do 2 turns in the boat) just keeps beeping and displaying meaningless numbers. If I ignore that and try to calibrate direction anyway, the indication ends up being pretty much random. So for now I'm still using the windex for direction.

Raymarine's tech. support said it was probably a faulty display, so I'm waiting for a replacement to arrive. From comments on this thread I suspect the speed indication may be on the low side too so I'll see how the replacement unit behaves.

I fitted the transducer at the mast head, I made a detachable mast cap, also carries combined windex and VHF antenna.

I bought an ST40 bi-data for depth and speed at the same time, with a transom-mount transducer. This works OK, although speed under power can be a bit off because of the effect of the prop. The transducer is mounted exactly per the instructions, but I guess with 50HP thrashing a prop that close it's bound to disturb the paddle wheel!

I have the two displays side-by-side on the port bulkhead. They look nice anyway. (You can just see them in this pic from the set I posted a while back)

Cheers, Rick

[Scott]

Rick, I have exactly the same setup as you plus a raymarine auto and wheel pilot.

I have been nothing but pleased with mine and they have performed flawlessly for years. You even have yours mounted where I have mine.

[bastonjock]

Scott,how di you get on with a spinnaker,did it improve your downwind performance,any suggestions on how to get a better downwind performance?

[Scott]

Weve had a lot of fun over the years with the stock Mac Asym.

Imo the best way to make way downwind is to not go directly downwind. On a dead run speed over ground is far slower and headway to waypoint is greater than on a broad reach.



In lighter winds (7 and under or so) We haul the tack in tight and treat the Spin like a big jib ( this photo is beating as hard as the asym would allow.



We sail the spin on the same side as the main most of the time. If we go wing on it is more for the impressive photo op than the speed.

[Boblee]

My favourite method of sailing is with just the spinnaker mainly because the wife doesn't get so agitated with surprise heeling as with the other two sails.
Don't seem to get a lot more speed with the main up anyway especially running straight downwind, now that the auto pilot is installed (almost) will try to do a bit more.
Don't seem to have a problem with rounding up in fact the reverse is the problem as the mast is raked well forward, maybe I just don't push it hard enough in good winds?

[Tony D-26X_SusieQ]

i was out yesterday and had the wind drop quite a bit so i ended up sailing downwind,the sea was just pushing me around,there was very little forward motion under sail,the best i could get was 2.3knots,i did manage to briefly have the boat gull winged but the wind kept moving around so i furled the jib and ended up snaking all over the place with a following sea,id like to try it with more wind,but does the handle so badly downwind?

The Mac handles very poorly in following seas if you are moving slower than the current. The waves will bat the stern arround all over the place. Try the iron genny and get your speed up faster than the waves and she will handel a lot better. Otherwise you will be fighting the helm the entire way.