Length vs Beating, course vs pounding

[MartinR]

Originally Posted by Dave_S

I've posted about this on here before but it doesn't get much support from the crowd.

I like the idea of T foiling rudders for my cruise boat.

They are almost always used to provide foil assist... i.e. lift. Most outcomes for this end with cruising catamarans not having the power to weight ratio to allow the foils lift to overcome drag and end up with a net loss.

My plan is to have 0 lift when the boat is at it's no sea state sailing level. However if the boat chages from level by X degrees the T foil will change by the same amount, this moves the pivot point of the boat backwards so it will behave similar to a much longer boat.

This should result in a number of benefits with smaller losses. This is not my idea it has been used before successfully on a smallish number of boats, most smaller and lighter. I have yet to see a flaw in the idea.

I'll let you know over the next year or so.

I guess, beating you will have very little advantage from this, but always worth a try.

[tomtriad]

I agree with Stu. It's more important how you handle your boat than how "heavy" it is. That said, a longer waterline will always give you better performance. It sounds like you had a very experienced crew aboard your charter who knew the boat and the passage well and I think they would have done well with any of the other boats you met that got roughed up. Beating up the Francis Drake channel in sheltered seas is a whole different ballgame than beating to weather against the trades from Panama to the VI.

[Sailor 99]

Originally Posted by MJH

Don't get too carried away thinking that LOA "alone" will give you the best COMFORT ride. I checked my database of over 4,000 sailboats for Beneteau's at about 50' and came up with the following COMFORT (equation taking LOA, LWL, Beam, and Displacement numbers) figures:

Beneteau Sense 50; 27.7
Beneteau Oceanis 50; 27.2
Beneteau First 50; 29.5
Beneteau 50; 30.3
Beneteau Oceanis 500; 24.7
Beneteau 510; 26.6

For comparison look at the following sample of other designs less than 50':

Valiant 40; 34.4
Tayana Vancouver 42; 43.7

With an acceptable range of 25-50 COMFORT rating, Beneteau 50s barely make the grade even with their longer length; don't count out shorter LOAs. Do your homework. Numbers don't lie.

~ ~ _/) ~ ~ MJH

Look at Beneteau Idylle 51. Motion comfort is 33.67. Compare this boat with all of those Beneteau's above and I will bet money you will find that the Idylle has a deep hour glass shaped hull and the others all have flat shallow hulls.

[markbarendt]

Originally Posted by ancor

BVI, seastate is the factor, not the wind strength, especially if the breeze only just came up.

I agree that seastate is the larger factor.

The seastate at the Soper's hole end was fairly confused, choppy, white capped, and short in interval. Height was probably running 3-4 meters.

[MartinR]

Of course, sea state is the big factor. Smooth water and 40 knots of wind is fine. Except for the noise of course

[Singularity]

Interested in this question I googled it. Then I came back.

The punchline answer to the OP question is, in a nutshell, work (in the math/physics sense...incidentally developed by Coriolis but having nothing to do with the Coriolis effect). You must coalesce all the variable discussed with particular consideration for the relatively under-appreciated concept of effective (working) LWL (and how much work it does as distributed) as the hidden variable (relationship). After that it's pretty much how long/tall the boat is vs wavelength/height (eyeball stuff) for most intents and purposes (when all else held equal). All this with respect to monohulls applicable to 95-99% of cruisers.

Otherwise quite analagous to wing loading in things that fly, and the variables associated with wings moving through air masses and vertical shear.

The answer was provided in a different sailing forum by an expert banned from this forum. 7 pages of turning in circles for want of someone to explain this.

[markbarendt]

Originally Posted by MartinR

25 knots apparent or true, real wind or from masthead instrument? If from masthead instrument, reduce by 15 or 20% unless the instrument is calibrated for height. Yes, sometimes beating can be comfortable and sometimes not, depending mostly on wave period. Correct reefing helps, in choppy sea though, more sail area is needed to push through, though. Longer boats are generally of course more comfortable beating up, though not every time. Narrow boats are at a disadvantage, as they heel more, but the positive is that they roll less. This is a complicated equation, giving different results each time,-).

Actually, long keeled traditional boats tend to give a more comfortable ride "uphill", although slower. So, on a modern boat you will have less comfort, but for shorter time.

True wind as reported by several weather services in real time, indicated verified the reported wind on all 3 boats that the school had sailing there.

My experience there, supports your thought that sailing to windward comfortably is a complicated dance.

When we have lots of variables we can adjust to find the 'best' balance, in this case I'm defining best as manageably comfortable.

The stories I hear of epic journeys to windward all seem to have common themes.

First and foremost is a deadline (many of the rest seem to stem from this seed).

Second is not paying proper attention to the weather, getting 'surprised' when conditions turn out 'as predicted' rather than 'as hoped for', then racing to get to protection.

Third is trying to follow closely the rhumb line direct to ones destination rather than a practical angle to the wind.

The list goes on...

[markbarendt]

Originally Posted by tomtriad

I agree with Stu. It's more important how you handle your boat than how "heavy" it is. That said, a longer waterline will always give you better performance. It sounds like you had a very experienced crew aboard your charter who knew the boat and the passage well and I think they would have done well with any of the other boats you met that got roughed up. Beating up the Francis Drake channel in sheltered seas is a whole different ballgame than beating to weather against the trades from Panama to the VI.

Yep, had a great and experienced tutor.

Yes, I understand that passages outside will be different.

[secrabtree]

Reading this thread I notice that different people have different ideas of what the word "beat" or "beating" means. Some use the sailing meaning "to sail as close to windward as one can" and others use the meaning that landlubbers give to the word "to pound". I have found that in certain conditions heating to weather is more comfortable than running (sailing with the wind coming from aft). One such condition was coming from Hawaii to the mainland - a dozen different passages - when running the apparent wind was very little and the heat and humidity was very uncomfortable. But changing course to a beat, or nearly so, substantially incfeased the apparent wind and made things much more comfortable. There are three common ways to return to San Francisco. #1 is to sail almost directly north with a following wind. By the time one gets to the latitude of Portland or Seattle the wind direction chnages enough that you're headed east. Then you get near the coast and have to head south along the coast to get to SF. Again, you have a more or less following wind. More comfort. But passing Point Mendocino and a couple other headlands you have a washing machine ride. #2 is to head straight towards SF. Carry lots of fuel because there'll be DAYS of steady motoring. And, while passing through the high, calm winds and hot humid days are very uncomfortable to me. By 'accident' I discovered that I could head southeast towards Ecuador on a port tack and that the wind direction continually changed and I passed within sight of the Farralons on the same port tack. Total time between 14 days and 23 days (most closer to 14). Standing with one foot shorter than the other doesn't bother me, and for relief I'd stand facing athwart ship - or lay down and get some sleep with one of my crew on watch.

[Dave_S]

Originally Posted by MartinR

I guess, beating you will have very little advantage from this, but always worth a try.

Not so.........in theory. Like most things it won't all be as good as it sounds.

In theory.

As the boat goes bow up the foils angle of attack goes up, giving positive lift aft, lifting the stern. As the bow goes down the stern gets negetive lift pulling it down. The effect is a flatter boat, less water is displaced and a smoother ride.

Added benefit #1 is the smoother ride which means the top of the mast is not changing the apparent wind speed and direction as much allowing better use of the breeze.

Added benign #2 is the rudder will provide more lateral lift requiring less rudder angle for the same result.

Added benefit #3 The smoother ride means you don't need to slow down as much if too fast for the conditions.

Added benefit #4 with more consistent boat speeds you can point higher

Added benefit #5 less stress on the boat.

Added benign #6 less drag in anything other than calm sea state and very low boat speeds.

[ScottMeilicke]

We have a fairly comfortable boat, ketch, 43’, 30k pounds, sails well. When we beat from MX to San Diego, US in 20-25 kn true, I found the boat was fine, but we struggled to get the most out of her. Not because it was difficult technically, but because we were at it 24/7, with a family crew possessing little upwind experience. For us, after a while it was hard to find the energy to experiment - angle of attack, sail config, etc. While I am book smart, I am experience dumb and in retrospect, wished I had tried a lot more tweaking. I’m sure I could improve comfort and VMG if I did it again. At least I think I can, from the comfort of my couch, LOL.

[Paul L]

Originally Posted by markbarendt

I agree that seastate is the larger factor.

The seastate at the Soper's hole end was fairly confused, choppy, white capped, and short in interval. Height was probably running 3-4 meters.

Really, you are comfortably beating into 25kts true or low 30s apperent and it was 3 to 4 meter confused seas, aka 10 to 14 feet. I think you might be exaggerating your point a bit, either the seas or the comfort level.

[markbarendt]

Originally Posted by Paul L

Really, you are comfortably beating into 25kts true or low 30s apperent and it was 3 to 4 meter confused seas, aka 10 to 14 feet. I think you might be exaggerating your point a bit, either the seas or the comfort level.

My estimation is surely suspect given my limited time at sea, and I may be struggling with the conversion given my 1st language of measurement uses yards, but we were pretty well hiding the boat and ourselves in the troughs at the Soper's hole end of the journey.

[markbarendt]

Originally Posted by ScottMeilicke

We have a fairly comfortable boat, ketch, 43’, 30k pounds, sails well. When we beat from MX to San Diego, US in 20-25 kn true, I found the boat was fine, but we struggled to get the most out of her. Not because it was difficult technically, but because we were at it 24/7, with a family crew possessing little upwind experience. For us, after a while it was hard to find the energy to experiment - angle of attack, sail config, etc. While I am book smart, I am experience dumb and in retrospect, wished I had tried a lot more tweaking. I’m sure I could improve comfort and VMG if I did it again. At least I think I can, from the comfort of my couch, LOL.

One of the things my wife had decided before we finished our upwind passage was that our buddy Otto (whose last name is pilot ) was going to be a permanent member of our crew.

[markbarendt]

Originally Posted by secrabtree

Reading this thread I notice that different people have different ideas of what the word "beat" or "beating" means. Some use the sailing meaning "to sail as close to windward as one can" and others use the meaning that landlubbers give to the word "to pound". I have found that in certain conditions heating to weather is more comfortable than running (sailing with the wind coming from aft). One such condition was coming from Hawaii to the mainland - a dozen different passages - when running the apparent wind was very little and the heat and humidity was very uncomfortable. But changing course to a beat, or nearly so, substantially incfeased the apparent wind and made things much more comfortable. There are three common ways to return to San Francisco. #1 is to sail almost directly north with a following wind. By the time one gets to the latitude of Portland or Seattle the wind direction chnages enough that you're headed east. Then you get near the coast and have to head south along the coast to get to SF. Again, you have a more or less following wind. More comfort. But passing Point Mendocino and a couple other headlands you have a washing machine ride. #2 is to head straight towards SF. Carry lots of fuel because there'll be DAYS of steady motoring. And, while passing through the high, calm winds and hot humid days are very uncomfortable to me. By 'accident' I discovered that I could head southeast towards Ecuador on a port tack and that the wind direction continually changed and I passed within sight of the Farralons on the same port tack. Total time between 14 days and 23 days (most closer to 14). Standing with one foot shorter than the other doesn't bother me, and for relief I'd stand facing athwart ship - or lay down and get some sleep with one of my crew on watch.

Nice accident. Is there a season it works best in?