Terrorized by Gusts!

[Doug W]

What is the best position for the traveler? When using the main, I tend to center it regardless of wind speed and regardless of point of sail.

Bob,

I must add that I am very lucky in that the Admiral enjoys sailing at over 30 degrees We have done over 45 and she has not complained You get the best speed at 10 to 20 degree heel, but the most thrills are at 35+. Ya ain't going fast, but you sure do get people's attention. Yehaa

Ray

I am lucky, my wife does not think we are sailing until we hit at least 15 degree lean... She likes it 30 to 35 better! She would have thoroughly loved the sail I had last Saturday.

...Doug

[mika]

Thanks, all, for your comments and advice re my challenging day with severe wind gusts. During that adventure, I was doing most of everything that you all advised. . . . I was taught to sail as a child many decades ago, and my teachers made me swear to never touch a motor or a paddle when being challenged while under sail, so I have a natural aversion to using the iron horse as advised by one of you. Admittedly, there does come a time when it may be foolish to not do everything possible to avoid calamity, but in this instance I was never out of control or in any real danger. By the way, I do have a good topping lift and I didn't see it mitigating my situation. As I said at the outset, now that I know this vessel better, when "gusts" are forecast, I will always reef when first hoisting my main and heading out.

Here's a related question: When our boat, or any monohull sailboat for that matter, goes into an extreme heel, isn't it supposed to automatically and naturally "round up" to some extent, even when the skipper does little ? If so, I don't think I have experienced that phenomenon. Perhaps I have never allowed it play out long enough for that to happen. Of course, as we all know, if you release all tension on your mainsheet, the boat will go into irons.

I also sailed a Sunfish for 15 years, had a Catalina 22 for a few years, and have sailed on a number of other sailboats. IMHO, my Mac M is more challenging and less forgiving. (That doesn't mean I don't love this boat.) Again, IMHO, it certainly has a greater propensity for heeling and heeling further than other sailboats when all are subject to the same wind velocity. I witness this when I'm on the water in the vicinity of other sailboats. I'm not the only Mac owner to say this. Perhaps our higher center of gravity, higher freeboard, and greater distance from the water's surface sometimes creates the illusion that the heel is greater than it really is?

Thanks again, everyone.

[ROAD Soldier]

Sorry ROADSoldier, I though that was a link to Mika's inquiry and call or advice--my apologies to you if I offended you.

T

Bob

The Annapolis Sailing Book is correct when they say "too far". Trimming is a baby step adventure

No you didn't offend just amazed me. I can only imagine having one of my best and a fun time thinking I am the greatest then post a pic of that fun time thinking everything is perfect. Then have come in a pick it apart, it is those gut wrenching criticisms we learn from. Especially when your the boat or guy in the picture .

[mastreb]

When our boat, or any monohull sailboat for that matter, goes into an extreme heel, isn't it supposed to automatically and naturally "round up" to some extent, even when the skipper does little ? If so, I don't think I have experienced that phenomenon. Perhaps I have never allowed it play out long enough for that to happen.

The Mac will round up when way over. In heavy seas I once heeled to about 60 degrees and it rounded up right quick. Thankfully.

it certainly has a greater propensity for heeling and heeling further than other sailboats when all are subject to the same wind velocity.

This is due to the flood ballast. Because the seawater ballast weighs the same as the seawater you're floating in, there's essentially no resistance to heeling at all (other than drag on the daggerboard/centerboard) until quite a bit of the ballast tank is out of the water. That makes these boats "tender", with a tendency to heel over quickly until the ballast tank is out of the water. With fast reefing of the jib you can generally keep them to a 20 degree heel in light or moderate winds pretty easily.

Same reason that in port these boats bob easily from side to side compared to a full keel boat.

Matt

[Catigale]

and my teachers made me swear to never touch a motor or a paddle when being challenged while under sail

This kind of crap isn't teaching, it's dogma. I know the intent is good, but the best way to learn sailing in a Mac is with the engine at idle to bail you out if needed. I climbed most of my learning curve on a tidal estuary with commercial shipping...not having motor backup would certainy put me in the Dar-lose club.

I've also found my doesnt go to irons with a loose main sheet above moderate winds...under the right conditions the high freeboard can catch the breeze and sail off downwind.

[bscott]

The greater the mast rake = more weather helm. The mast seems to be trimmed more neutral than the and I think it is due to the need to reduce the binding action of the rotating foot when raked vs the lighter constructed mast.
The position of the CB will also affect the amount of weather helm and pointing

Bob

[Hamin' X]

it certainly has a greater propensity for heeling and heeling further than other sailboats when all are subject to the same wind velocity.

This is due to the flood ballast. Because the seawater ballast weighs the same as the seawater you're floating in, there's essentially no resistance to heeling at all (other than drag on the daggerboard/centerboard) until quite a bit of the ballast tank is out of the water. That makes these boats "tender", with a tendency to heel over quickly until the ballast tank is out of the water. With fast reefing of the jib you can generally keep them to a 20 degree heel in light or moderate winds pretty easily.

Same reason that in port these boats bob easily from side to side compared to a full keel boat.

Matt

Not true. It has to do with the length of the moment arm and the high center of rotation. The water ballast is not in the water, it is in the boat.

~Rich

[mastreb]

If we want to be very technical, it's the metacentric height of the boat that causes it to be tender. Sea water Ballast lacks the specific gravity to to make a significant contribution to the boat's center of gravity, so resistance to heeling is low until the distance between the centers of gravity and the center of bouyancy is wide. The shallow moment arm is one contributor to that, the low specific gravity of sea water is another, and the high freeboard is a third.

The seawater ballast alone is not the whole story, but neither is the shallow moment arm.

[Hamin' X]

Nope.

[Hamin' X]

Sorry for the short answer, but I was on my phone internet.

Find a deep draft vessel and take a gallon jug of water down below the waterline. Place it on a scale and how much do you think it will weigh? That's right, the same as it weighs on the dock. The same is true with our water ballast. It is not being buoyed up by the surrounding water, rather by the boat itself. It has the same weight as if it were on the dock. Which weighs more, a pound of lead/steel, or a pound of water?

~Rich

[mastreb]

Sorry for the short answer, but I was on my phone internet.

Find a deep draft vessel and take a gallon jug of water down below the waterline. Place it on a scale and how much do you think it will weigh? That's right, the same as it weighs on the dock. The same is true with our water ballast. It is not being buoyed up by the surrounding water, rather by the boat itself. It has the same weight as if it were on the dock. Which weighs more, a pound of lead/steel, or a pound of water?

~Rich

You are correct, it is the moment arm (or righting arm) of the entire boat, not just the ballast tank, that effects stability. There are more factors, but my understanding of it was entirely incorrect.

There's an entire discussion here: http://en.wikipedia.org/wiki/Metacentric_height

Read the section on "Free surface effect" if you want to know why it's absolutely imperative that the ballast tank be full: You're apparently better off with no ballast than half ballasted, because a half-ballasted tank may be able to setup an ever-increasing roll that can eventually capsize a boat. I'm guessing that the shape of the tank on a Mac would have some damping effect, but that explains why the manual warns against it.

[dca81]

Wow...great technical analysis and discussion...I think??? Don't know if you are a technical guru Mika but I am just a simple accountant, now retired and relatively new to sailing (only 2nd year), so my response is much simpler... The does "round up" on its own. I experienced this, twice, on my second sail when I was overwhelmed by unexpected gusting winds. I did not have time to look at the inclinometer, but the water level was over the rub rails but did not come into the cockpit area. The second time the boat rounded it moved laterally (to port ) slightly before rounding out. Terrifying is an appropriate description of this experience since my wife was holding on to the lifelines screaming and I was thinking I guess I really should have put that PFD on!!! But the boat saved us by doing what is was designed for, regardless of what you idiots do. So here I am a year later, and still sailing the same high mountain lake (9100' altitude) with very unpredictable winds. We encountered very strong gusts on yesterday's sail, but we furled the jib and reefed the main. Boat was very stable (probably never heeled over 10 degrees) and reasonably responsive to my commands. IMHO, yes it does heel easily for all the reasons you mentioned, but with a little experience you can normally adapt to the situation and keep the boat at a reasonable heel (whatever you like) and responsive to your commands.

[Ixneigh]

I thought right away my M was too tender to carry enough sail to thrash through chop. I added 250 of lead on either side of the main ballast tank. While not in the idea place which would be glued to the bottom i am sure it will have a positive effect on keeping extreme heel down. If it eorks ill glue it to the bottom later with fiberglass added. See if it works in a month or two.

[DaveB]

You already have a 300 lb ballast. You would be wrong if you tried to change the ballast of a M.
Anything outside the center of effort is total useless and can create a captize .
Learn how to sail the Mac.X-M. it is very well centered and can do a 45 degree knockdown and come up right.
Never consider this boat as a full deplacement boat for offshore cruiseing.

Dave

I thought right away my M was too tender to carry enough sail to thrash through chop. I added 250 of lead on either side of the main ballast tank. While not in the idea place which would be glued to the bottom i am sure it will have a positive effect on keeping extreme heel down. If it eorks ill glue it to the bottom later with fiberglass added. See if it works in a month or two.

[Ixneigh]

Its an experiment. Easy to remove if need be but secure from movement. I dont trailer often. I sail often. I know how to sail the boat upright and how not to overpower her. Plus i got no rail meat for additional righting.
I wont thrash the boat till i acertain the effects. I can sell the lead probably for more then i paid at the rate things are going.
Ixniegh

the biggest obsticle to any offshore work is the marginal rudder setup if you ask me. And i know no one is