CD28 weather helm and autopilot

[edmundsteele]

I purchased the Magnolia Glen, a Cape Dory 28 last September and sailed her from Stuart, Florida on 4th. November 2019, bound for Puerto Rico. On the second leg of the trip, I was sailing south towards Fort Lauderdale when the wind picked up into the 17 to 20 knots range, directly on the beam. The waves were forecast to be in the 2 to 4 foot range and for a while I was getting 8 footers, again directly on the beam. I put the second reef in the main, reefed in the Genoa a little with the newly installed furler and I was still making 6 knots and sliding off the backs of waves at 8. Okay, here is the question. Even with two reefs and the main eased, I still had lots of weather helm and the Simrad TP32 autopilot was struggling and getting hot to the touch – thus I turned it off and hand steered for the next couple of hours until the wind died down a little. Is this typical behavior of the Cape Dory 28? Are conditions like this too much for the Simrad unit? Any thoughts or recommendations on how to balance this better?
Fair Winds,
Ed

[Jim Walsh]

I purchased the Magnolia Glen, a Cape Dory 28 last September and sailed her from Stuart, Florida on 4th. November 2019, bound for Puerto Rico. On the second leg of the trip, I was sailing south towards Fort Lauderdale when the wind picked up into the 17 to 20 knots range, directly on the beam. The waves were forecast to be in the 2 to 4 foot range and for a while I was getting 8 footers, again directly on the beam. I put the second reef in the main, reefed in the Genoa a little with the newly installed furler and I was still making 6 knots and sliding off the backs of waves at 8. Okay, here is the question. Even with two reefs and the main eased, I still had lots of weather helm and the Simrad TP32 autopilot was struggling and getting hot to the touch – thus I turned it off and hand steered for the next couple of hours until the wind died down a little. Is this typical behavior of the Cape Dory 28? Are conditions like this too much for the Simrad unit? Any thoughts or recommendations on how to balance this better?
Fair Winds,
Ed

Some very good advice here http://forums.sailinganarchy.com/index. ... full-keel/

[kerrydeare]

...even with two reefs and the main eased, I still had lots of weather helm and the Simrad TP32 autopilot was struggling and getting hot to the touch ... Are conditions like this too much for the Simrad unit? ...

Probably too much for most tiller pilots, but unfortunately these are conditions you'll likely encounter often.

I just read the article Jim posted and it's full of good ideas and suggestions. I don't know if they got into it but when reaching along like this, even with a moderate sea running, you could just dump the main altogether and let the jib do the work. This is not something you want to do going to weather because it puts an unfair strain on your rig, but once cracked off to a real reach you should be fine. If not just dial in a little less jib.

Eventually you may consider a wind vane in addition to an electronic pilot. I have a Navik on my CD 28 and like most vanes, the heavier the air (up to a point) the better the vane steers. This is particularly true on a reach or even a broad reach. It also adds another level of complexity, so "you takes your choice." Of course 20 knots offshore is quite different from 20 knots on the bay, and the added motion can make for a long day.

[edmundsteele]

Thank you for the link to the “reducing weather helm” discussion as well as for the comments on tiller pilots. I left the Magnolia Glen on a mooring in Georgetown, Bahamas until next February and still have nearly a 1,000 miles of open ocean sailing to get her home. Will try to limit passages to forecast wind in the 10 to 15 knots range but you know how that goes. I think that the strategy of dumping the main altogether might be the trick. I have a storm trysail (came with the boat) that I haven’t tried to rig yet.

A wind vane would be great but that isn’t going to happen on this trip. I did just buy a second tiller pilot on eBay so at least I have a spare now.

[John Stone]

In boats like ours the key is to always reef the main first. So get those two reefs in as you did. If you are not over powered with the jib, hold off on furling it. If you are not overpowered and still have weather helm start easing the main out as far as necessary. It might even back wind along the luff. That is normal. But you also need to apply some vang because it controls the leech and also if the boom is going up and down the mains’l is rubbing on the leeward shrouds and the chafe will damage it. The Vang helps prevent that. There should be very little weather helm at that point. If you are beam reaching and still have weather helm drop the main altogether. And sail under the jib or better yet the stays’l. I once sailed for four days in 25-35 knots and 10-14 seas on a close reach in the trades and all I had up was a reefed stays’l. We still made 5.5-6.5 kts. The boat was perfectly balanced.

If your sails are blown out that contributes to weather helm. Also, make sure your mast is nearly plumb and and the boat is trimmed so she is on her lines. If she is overloaded in the stern or the mast is raked aft that contributes to weather helm. Often it is not one thing but all these things combined together.

I don’t have an auto pilot. I rely totally on my windvane. And no windvane or autopilot can overcome excess helm. Balance the boat first, then engage the autopilot or vane.

[fmueller]

"always reef the main first"

I had a working jib made for me by Quantum this summer. It's about 90% and trims to the OEM tracks on my coachroof which I upgraded to 1" . That sail and full main produce far less weather helm on my 27 than my hi cut 115% + main reefed to the first reefing point (about equal sail area) and is nearly perfect in 15 knots, gusting to 20 and points higher as well.

If I fly that jib and reef the main to the first reefing point, I can sail close hauled into 25 knots apparent at 35 - 40 degrees apparent easily making over 5 knots into choppy seas. The boat is just terrific in heavier air with one reef in the main and the working jib flying.

My conclusion is that in moderate to heavy air our boats should be flying working jibs, not genoas, and that weather helm is more complicated than just center of effort / center of resistance. Rolling up genoas is not the same thing - the trim angle and foil efficiency are compromised and in almost all cases the main will be trimmed too tight relative to the slack angle of the jib sheeted to toe rail tracks just accidentally.

The Raymarine tiller pilots are light air / motor power only devices at best.

Consider this if you want to stick with a tiller type pilot:

https://pelagicautopilot.com/

https://www.youtube.com/watch?v=ZkXUYVL ... be&t=4m26s


my 2 cents

Fred

[Steve Laume]

You received a lot of good advise.

What caught my attention is that you have a new roller furler. It could be that it is set up with the head stay a bit too long. This would give you some mast rake that might be causing some of the problem. Raven had a bit more weather helm than I would have liked at one time. When I had new rigging made up, I had them make the back stay an inch longer. I am not sure how much effect this had but it didn't hurt. A nice flat, crisp, new main definitely makes a difference, Steve.

[edmundsteele]

Good point on the mast rake. I just had the fixed rigging replaced because although it was judged to be in very good condition, it was 38 years old. The roller furler was installed at the same time. I did eyeball the mast and it looked straight enough and not raked but I noticed that in a moderate crosswind, it “pumps”. That is, it oscillates a half inch or so in a fore and aft direction. Annoying but not hazardous. Past and ancient experience tells me that the way to reduce this is to introduce some curvature to the mast by tightening the forward lowers but I have yet to test the tension of the leeward shrouds when sailing close-hauled. I will test the plumb on the mast when I get back aboard. Phew! Who thought that sailing was easy!
Ed

[kerrydeare]

... Past and ancient experience tells me that the way to reduce this is to introduce some curvature to the mast by tightening the forward lowers but I have yet to test the tension of the leeward shrouds when sailing close-hauled ...

This is exactly how it should be done for the single-spreader/double lower rig (aka most Cape Dory boats). A while back there were several tech articles in the literature about this, and it was at that time I set the rig as you described. Since then (say, 30 years) whenever the wind came up and the headstay sagged, the mast was right "in column" and there was no pumping or other distortion in the rig. If you proceed as you've described you will be just fine. Our little boat took home a bit of silverware using this method.