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I have never logged a consistent wind measurement, (cuz I can't! ) Please forgive this question but I still do not have a decent wind instrument on 'boat' (as I am still waiting for some genius to solve our rotating mast issue) I do not have a good log of this type of data and I need some help with a wind calculation. I have a general idea what degree 'boat' will point off the wind as a stock rig lightly loaded, but I am in the process of making some rather long distance ocean leg planning that requires me to know more about the levels of performance that can be expected over more various conditions.

If you have an M boat with a stock rig, please tell me if you can, what exact degree you can sail your boat off the true headwind (not apparent) and if wind conditions make that degree less or more based on intensity - also - does the weight of your rig change anything?

I am trying to put together some really long Pacific legs encompassing hundreds of miles and I would like to tune up my calculations so I can plan the tacks accordingly. (Don't worry, I won't get lost at sea - I will at no time be further than 120 miles from an island or land mass). I just want to plan my tacks most efficiently with the very predictable prevailing winds we have over here. Any help would be appreciated.

tanky tanky

Boat...to get good data on this you need the GPS track not just the angle to,wind

It's very common for bad sailors to get a good heading to wind, only to be making little VMG due to slippage.

I really good at this, btw.

Isn't that what tacking is for? If you can't go directly to what you want, you tack, thus optimizing your Velocity Made Good.

Ray

NiceAft wrote:Isn't that what tacking is for? If you can't go directly to what you want, you tack, thus optimizing your Velocity Made Good.

Ray

VZmG tells the tale. It's possible to point higher to wind with lower VMG. It's common when people boast they can point to 30 degrees apparent on a Mac.

Catigale wrote:

NiceAft wrote:Isn't that what tacking is for? If you can't go directly to what you want, you tack, thus optimizing your Velocity Made Good.

Ray

VZmG tells the tale. It's possible to point higher to wind with lower VMG. It's common when people boast they can point to 30 degrees apparent on a Mac.

That's exactly my problems Catigale, I already have a lot of good vmg calculations for my legs and that's why I am talking about true wind, not apparent. I have the speed of course to plug in and my cosine from the true wind angles I have (historically VERY reliable, because I have already sailed all these legs many times!)

As you would have guessed by now I am trying to tune of my old charts from the 1970's with good tacking info - I need to recalculate for 'boat'. Problem is, I have a lot of places where I was getting angles that were 45 degrees off the wind and I'm not so sure I can do that with a stock genoa, and with the added speed that 'boat' has over my old boat I really don't need 45 degree legs. Some of these legs were over 250 miles.
If I use 50 degrees off true I will be adding tacks to the legs. I'm trying to calculate the most efficient routes.

Raise sails. Feel for wind on your face, look for wind on the water, look at your telltales. Set your sails for desired point of sail. Point your boat in desired direction. Sail. Enjoy! Don't overthink this Boat.

Some of these legs were over 250 miles.
If I use 50 degrees off true I will be adding tacks to the legs. I'm trying to calculate the most efficient routes.

No experience with this scenario, why are such long tacks desired?

Lee Ward wrote:Raise sails. Feel for wind on your face, look for wind on the water, look at your telltales. Set your sails for desired point of sail. Point your boat in desired direction. Sail. Enjoy! Don't overthink this Boat.

Yes, I remember back in the day - all we had was the wind back then. You never worried about things because "what good would it do?" The wind is what it is, the sea is what it is - your just along for the ride. If land is a day or two away then what good will it do to worry about tomorrow? You can only take it one day at a time. That was our motto - I remember. We had no real weather forecasts back then, no GPS, no 60 HP engines and boats that could go 20 miles per hour.

I totally get it - that's how I spent most of my life on the water up to this point. Then came 'boat'. All my old paradigms are changed.

'boat' changed a few things - I have choices now that I never had before. Do you guys realize that I can traverse the entire 600 mile length of the Gulf of California and never be more than 3 hours from land because of the power boat options on 'boat'?!? This totally rethinks my entire approach to the cruising I have done in the past! I need to recalculate EVERYTHING! This opens up more 'stuff' and more choices than I can even handle!

As I begin to plan my retirement cruises (knock on wood) I see the need to reconsider the increasing choices I have. I have based things on the ability to TRAILER the boat to more places (that's how we did it in the old days) but I see even more possibilities now too.

So, anyone have any reliable data on pointing performance?

Catigale wrote: It's common when people boast they can point to 30 degrees apparent on a Mac.

It is possible but very inefficient. We've done this to try and smooth out the ride beating into waves but speed drops to 0.5-1.5 kts. The biggest problem we have is sailing into higher actual wind speeds, is it appears the stronger the wind the higher you can point (for a bit about 15-20kts) but then the high windage and lightness of the Mac seems to counteract the forward momentum (=loss of speed) so you end up pointing further off the wind (to get more speed) then you heel more and lose your intended course. For us this has been limited to upwind sailing in winds higher than 20kts (You can leave the dock here with perfect conditions round the next point there’s a gale blowing with rain, go into a bay and its dead calm and sunny; not just that the weather changes fast but all three can happen at the exact same time ). Although we do take advantage of this effect and enhance it by pulling up the DB when downwind sailing we can run on a broad reach and sail the narrow channel all the way north using the side slippage to gybe less while not having to run wing on wing.

yukonbob wrote:

Catigale wrote: It's common when people boast they can point to 30 degrees apparent on a Mac.

It is possible but very inefficient. We've done this to try and smooth out the ride beating into waves but speed drops to 0.5-1.5 kts. The biggest problem we have is sailing into higher actual wind speeds, is it appears the stronger the wind the higher you can point (for a bit about 15-20kts) but then the high windage and lightness of the Mac seems to counteract the forward momentum (=loss of speed) so you end up pointing further off the wind (to get more speed) then you heel more and lose your intended course. For us this has been limited to upwind sailing in winds higher than 20kts (You can leave the dock here with perfect conditions round the next point there’s a gale blowing with rain, go into a bay and its dead calm and sunny; not just that the weather changes fast but all three can happen at the exact same time ). Although we do take advantage of this effect and enhance it by pulling up the DB when downwind sailing we can run on a broad reach and sail the narrow channel all the way north using the side slippage to gybe less while not having to run wing on wing.

That's been my experience too bob, but I never really thought I was pointing 30 degrees at those times. Is it really possible? The addition of the auto pilot in 'performance mode' has also really helped 'boat' stay on course when heeled over - this is very helpful because when the wind is variable we would experience some of those course changes you mention as the boat heeled over beyond 32 degrees. We have experimented with this and found it to be about .5 knots, just as you said - only the cool thing is that with the AP the .5 knots does not effect course heading anymore. This is also why I am recalculating legs - Auto Pilot by GPS did not even exist when I made all my original plans in the 1970's - we used wind pilots (thus TRUE wind was critical to route planning).

I really wanted to spare you guys all the details about why my charts from the old days will not work anymore and I figured you would just trust me when I ask: "What can your boat do off the true wind?"

My plan is to increase the constant I used for the velocity increase and fiddle with the cosign of the wind angle to see if I can come up with a general rule for tacking that applies to 'boat'. Sometimes it is better to drive off the wind a little for speed, but that must be compensated by distance. Also, the acceleration calculations I made for tacking are a big part of deciding the number of tacks and time of day. (The winds here are so predictable and have not changed one bit from the 70's - so much for global warming - I sure don't see it over here).

Anyways, you guys need to just trust me that I know what I'm doing.

So, what is our real pointing abilities gentleman? The truth, let's fess up and get this number.

30 degrees is possible IF you only want to do 0.5-1.5knts total overground speed . Will makes for a long 250nm leg for you. Personally 45-50 off true wind I find is the sweet spot depending on wind speed and wave action. You’ll have to post your proposed trip. I'm wrestling with one myself for this summer. Solo navigation of Admiralty Island. Might try and sail the whole thing less motoring into any harbours; Which if I do, it will be glass calm the entire trip.

I was thinking of plugging in 45 degrees as the end of the protractor but I was concerned I was being to optimistic. I think your number so far has me at 45 degrees.

Let's see if anyone else chimes in with any other numbers. Thanks for your figures.

These are things that are calculated for long legs because of the need to sleep at night too (when to wake up to make a tack and so forth). Man, I can still remember making blurry eyed sightings of the moon at 2 AM. Now I can just calculate it all on the plotter and get some sleep.

RussMT wrote:http://www.flyorsail.com/Wind_Instruments.html

A very fine instrument that I am considering russ, but what I really need are the capabilities of something more like this:

http://www.sailtimerwind.com/OptimizingTacks.html

Right now I am doing these calculations with Microsoft Excel - (I have to plug in the wind direction manually) - I could to that with any instrument I guess - but having the customizing of tack information recalculating against real wind conditions is a big help. It's not just the wind direction but what you do with it.

I am also looking at the Wind Sail option Ray Marine has and I and asking if their software accounts for Velocity made good.

So russ, tell me, how high would you say your M boat points?

BOAT wrote:So, what is our real pointing abilities gentleman? The truth, let's fess up and get this number.

Can't speak for the boats, but my with old, blown-out sails doesn't point very well.



The change in direction in the last two legs was from wind direction changes, as I was keeping it as close to the wind as I could without dropping speed. The straight line parts are where I put the notebook computer to sleep to save battery.

This was the last long(ish) trip of last season. The land curves to the south off the right side of the pic, and I was trying to get far enough along to stay on a port tack from there as the shore fell off.

My 85 YO FIL was getting antsy, so I gave up and fired up the iron genny and motor-sailed the rest of the way. If he isn't eating by 6:00 pm, he gets pretty grumpy, and we were going to meet folks at our destination who were bringing the food.

Me? I'd probably just keep sailing, way out from the shore, then a straight shot to our destination. <heavy sigh>