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 Post subject: Sailing Performance: Upwind on the ocean
PostPosted: 15 Oct 2021 16:49 
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Tactictian

Joined: 06 Sep 2020 10:08
Posts: 105
Ahoy.

We sailed from San Francisco Bay to Monterey and back last month. Coming back was all upwind. With about 15 knots apparent wind, we were sailing with the full genoa and 1 reef in the main. It was pretty easy to keep boat speed over 5 knots and an apparent wind angle about 40 degrees.

After the wind picked up to 20+ apparent we furled in about 2' of genoa and put the second reef in the main. With those settings we couldn't poing above 50 degrees apparent without boatspeed dropping to 4 knots or less. Sailing low at 5 knots or high at 3.5, our VMG was consistently under 3. Yes, we had the centerboard down. Waves were about 3-5 feet, so they didn't seem to be slowing us down much.

Is this about what we should expect for upwind performance, or were we doing something wrong?


 
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 Post subject: Re: Sailing Performance: Upwind on the ocean
PostPosted: 15 Oct 2021 17:19 
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Skipper

Joined: 13 Feb 2011 21:19
Posts: 349
Location: Canyon Lake, TX
I'd be curious to know what others think about this.

Personally, I think the genoa reef had more to do with the loss of pointing than the mainsail reef did. Did you move the genoa fairleads forward when you reefed it? Not moving the fairleads will cause the top of the genoa to open up and lose power. The way my boat is currently configured, in 20+ knots, I have to tack to change the fairlead positions so it doesn't happen very often.

I'm looking to get some low friction rings and run their leads thru the daisy sailtrack so that I can adjust the genoa leads without tacking. I hope.

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Master and Commander of the Sailing Vessel Impetuous
I'm not a complete idiot, some parts are missing.
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 Post subject: Re: Sailing Performance: Upwind on the ocean
PostPosted: 16 Oct 2021 06:58 
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Skipper

Joined: 16 May 2009 08:06
Posts: 251
Maybe this wasn’t an option but in those conditions I think the working jib and full main (maybe 1 reef) would have worked well.


 
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 Post subject: Re: Sailing Performance: Upwind on the ocean
PostPosted: 17 Oct 2021 09:52 
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Skipper

Joined: 29 Dec 2006 09:38
Posts: 656
I have the deep fin keel version, but had my T37 for many years on SF Bay. I agree that your pointing problem is likely the rolled up jib. Not sure how large your genoa is, but I would recommend just having a 95% and not more than a 115% for SF area. Anytime you roll a jib your pointing is going to suffer from the shape and leads and, in my experience, foam luffs do not help much. I get very close to 30 degree pointing but have a 6'8" keel, but I have sailed the Centerboard versions and with proper sail balance they will sail closer than 40 without trying. You do need speed to move the apparent wind forward so I would question why you reefed the main in the situation you described.

Ray Durkee
T37 #373


 
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 Post subject: Re: Sailing Performance: Upwind on the ocean
PostPosted: 18 Oct 2021 13:40 
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Tactictian

Joined: 06 Sep 2020 10:08
Posts: 105
We reefed when the helm loaded up consistently and we felt overpowered. As the apparent wind climbed from 15 to 20+, we alternated reducing main and genoa. We definitely aren't sure if we're reefing the right amount or at the right time.

Yes, we moved the jib leads forward to keep leech tension.

The comments here are making me think we might have over-reefed and under-twisted to depower.


 
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 Post subject: Re: Sailing Performance: Upwind on the ocean
PostPosted: 22 Oct 2021 17:16 
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Tactictian

Joined: 06 Aug 2020 09:02
Posts: 142
A few comments from my experience/perspective as a racing sailor FWIW...

First, I don't think I would rely on AWA as a particularly accurate indicator of pointing ability unless you have very high confidence in your instruments and calibrations. Try as I might, my AWA varies tack to tack with new Raymarine i60s. I prefer to look at my overall GPS tacking angles which account for leeway angle but also factor in current. I find that my actual tacking angle with full main and fully powered with 150% genoa (talking 15+ knots AWS) is over 90 degrees. If you assume something like 5 deg leeway each tack, you should see under 90 degrees tacking angle on your compass. The boat is moving along nicely though at well over 6 knots and I'd venture a guess that I'm making better VMG than the OP. I keep my bottom clean, have a feathering prop, and my CB is faired quite nicely. I think these things help a lot.

Sail shape and driving ability really has a lot to do with all this. T37 k/cb polars are out there and if they are accurate you should be able to sail close to upwind targets so long as your boat is fairly optimized and trimmed properly.

My impression having sailed the T37 a few thousand miles this year (much of it upwind, including NY to Chesapeake Bay last month in 20-30 knots) is that the boat likes to sail powered upwind with the rail near the water. It likes some helm which keeps the boat tracking properly. While reducing sail and moving the CE of the sailplan forward makes for a more balanced helm, it may also hinder how the boat tracks and you may end up oversteering some if not really working hard to stay focused. More balanced is definitely better if you are sailing with an autohelm and you are worried about power consuption.

I do think that taking that first reef in the main before furling is the way to go if you are overpowered with a smaller headsail up (I have a new main with lots of roach and a new 115%). This allows you to put some leech tension on for point w/o getting overpowered. I also think that if you have a furler like the Harken or Selden that allows you that "free first turn" to take out some of the depth in the jib without really taking out area you will see improved sail shape when the breeze is on.

So, my experience is that the T37 points OK but ultimately it is limited by several factors not all of which we can control. I would expect the deep keel version to point significantly better because of a more efficient keel shape as well as a lower VCG.


 
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