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kadet wrote:

What IS the reason the boat tipped over?

Crew member "Hey look over there...."

rest of crew mover over to that side to look then .. OH! Bugger

I don't see why this is so hard to believe, 11 people that's like 700KG 2 metres above the water the ballast would not have stopped it flipping only made it self righting after it flipped. The question is not why it didn't flip earlier the question is by what miracle did it stay upright for so long.

And with a drunk captain at the wheel who knows what might have happened

I read all the witness accounts I could find on the internet and the court records and all were very clear that no one on the boat moved at the time the boat capsized.

The only plausible thing that Kevin mentioned is the idea of making a turn under power - the one thing I can't find in the stories is the position of the centerboard at the time the boat flipped - if the pilot made a sharp turn even at slow speed with the centerboard down it would indeed capsize the boat. I'm thinking of a situation where the motor is in a fully turned position and then a throttle up from the helm - that would tip the boat over before it even got to 6 knots.

I think the boat would have been unstable and even tipping over before he departed if it was only from the people on board - I still think it's more than that - there were way too many people around and on that boat and the other boat to be so completely unaware that the boat was unstable and only staying afloat because it was tied to another boat - someone would have noticed.

I am still trying to get the truth on this - the guy at the helm would know the answer if he were able to remember what he did just before the boat turned - I wonder what he might be hiding. I think there is a throttle issue that is not in the stories, but how can I know for sure? I would like to know the answers - I would love to interview all concerned.

BOAT,

You are making assumptions, and then using them as facts. Not a way to establish a factual argument. I am using “argument” in the debating way, not the heated exchange meaning.

I would'nt assume that anyone on board that boat was attentive to it's stability. They were partying.

There also were conflicting statements about how fast the boat was moving. As slow as walking speed (6MPH), to moving fast.

At this point, I think you have too much time on your hands to dwell on this so long. I for one, am giving you the last word in your next posting on this, that, is if you deem it so important as to need to post it. This isn't worth it. Life is too short. Go sailing.

Ray

If the 1400 lb of water ballast is in, and the crew is small and in the cockpit (low), the center of mass is low, and the boat is stable beyond 90 degrees. The cartoon pic below is just an eyeball approximation, but shows the principle.



If the boat that flipped had no water ballast, but did have 1400 lb of people, mostly on deck, the center of mass is much higher. The angle of vanishing stability is much less than the design condition. It's stable to some degree, like a common power boat, and wouldn't necessarily flip just from moving around on deck, but give it a little push from a wake, or engine thrust with the wheel hard over, and it doesn't take much to start it moving. Dynamic effects also come into play. People flopping to the low side makes it worse, fast.



It sounds plausible that it would be stable enough sitting in calm water, but go over relatively easily with enough of an impulse from a wave, engine thrust, falling crew, so some combination thereof, with no water ballast in and way too many people exactly where they shouldn't be (high up).

I'd be curious to know what the angle of vanishing stability is for the empty boat, with 50 hp OB, and no ballast.

From your drawings it looks like the boat would indeed still be rather stable with 11 people on deck because of the center of buoyancy - I think we might be back to that characteristic that is akin only to the X hull - floating on the corner with a sudden tip from 30 to 45 degrees - it's that same phenomenon that seems to scare X drivers from heeling their boats more than 35 degrees -

I need to ask you X guys - is there a sudden change in the feel of the boat as it heels from 35 to 45 degrees? Is the change in heel sudden, faster, or jarring?

Wouldn't know. Anytime it gets to 25+ degrees it's time to bring it back.

BOAT wrote:From your drawings it looks like the boat would indeed still be rather stable with 11 people on deck because of the center of buoyancy - I think we might be back to that characteristic that is akin only to the X hull - floating on the corner with a sudden tip from 30 to 45 degrees - it's that same phenomenon that seems to scare X drivers from heeling their boats more than 35 degrees -

I need to ask you X guys - is there a sudden change in the feel of the boat as it heels from 35 to 45 degrees? Is the change in heel sudden, faster, or jarring?

I've thought a lot about this.

My best guess is that the keel was down. Under power at six or seven knots when you initiate a turn, the boat leans into the turn and feels fine. With the keel down, though, the boat rolls quickly to the outside of the turn, and could certainly have been the catalyst to start the death roll. If you are familiar with your boat you notice right away that it's not behaving properly. If you're drunk and unfamiliar with the handling characteristics you might try to keep on accelerating instead of correcting the problem.

There are a few old threads about what happens when the X keel falls accidentally while under power. The boat rolls over on its side real fast and the captain has to cut the power instantly. Even on this forum in the features tab there is a story about someone's trip to the Bahamas, where the keel rope broke on the trip back and the boat instantly lay down on its side, scaring the daylights out of the captain. There were only two on board in that story, and the author said that the boat took a while to come back up on its feet.

I've also seen some remarks in this thread about the weight of 11 people and two dogs. 8 American adults, 3 children, and two dogs could possibly weigh 2,000lbs. Combine that weight, some of it on the cabintop, with a dropped keel and a turn under power with possibly full throttle at 8, 10 or even 12 knots (no one really knows), then a capsize is actually likely, I think.

I've had my X in some full throttle' high speed turns with me and four big guys outboard, two on the cabintop, bouncing through waves and wakes with (accidentally) no ballast, and it felt nothing but stable. I think it was the keel that caused the capsize.

The other possibility is that a raft-up line got caught and initiated the roll. I know that a person on the other rafted boat testified that the lines were clear, but that doesn't mean that's true.

After reading about the case I don't think the captain should have been convicted, especially if my theory about the keel is right. Whoever lent him the boat probably failed to warn him about the keel-down risk, and the maximum load. It wasn't the captain's boat. On the other hand, maybe if the captain wasn't drunk he could have responded faster to the roll, or noticed the sensation of rolling away from the turn instead of toward it and responded faster and more logically

The captain does seem to be a shady character, with other convictions on his record, and many years of jail time in his past.

Starscream wrote:I've thought a lot about this.

My best guess is that the keel was down.

Yeah, meee tooo - I really think this is what happened too star, I think the guy did a throttle up and rolled right into a turn.

Starscream wrote:I've thought a lot about this.

8 American adults,

Ahh, yes, and I would expect a guy from another country to bring up the obvious - yes - these were American Adults so it's a good guess they were indeed much fatter than the average human being. The fact that no MAC outside of America has ever capsized was not lost on me when I was looking into this - there is indeed a good possibility that the 'fatness' of the people had a lot to do with this and also toms drawing makes me consider that the fat people started rolling to one side when the boat began to tip over and that was the genesis of the death roll.

dlandersson wrote:Wouldn't know. Anytime it gets to 25+ degrees it's time to bring it back.

See! Now those are the kinds of comments that just don't add up for me! I hear these kinds of comments from X drivers A LOT - and I must accept what they say - no one knows the X boats better than the X drivers - and I hear a LOT of X drivers telling me they do not like to drive their boats past 30 degrees - I hear it A LOT. Yet, from the M boat people they don't seem to be so concerned about sailing at 40 degrees and talk about it all the time like it's no big deal. And being an M boat owner, I can tell you that I have never felt in any danger at 45 degrees and the boat rides just fine at that angle and no one is panicking - so I think there must be some sort of difference in the feel of the two boats once you get past 30 degrees. Someday I need to get on an X boat and push it over and see what all the fuss is about.

No, no, Boat, the weight comment was really meant towards the American dogs. Those things can easily weigh 450 lbs each from what I've read.

Under sail with ballast The X behaves fine at 45 degrees. Not the best technique to make headway, especially with inexperienced crew, but 45 is no problem. When my boat gets just a bit past 45 it rounds up in the gusts; can't stop it. I love running it at 30+ degrees just for the feeling.

I was out with my cousin once, full sail and full jib in 20kn wind gusting to something higher than that, and we intentionally tried to get the boat onto its side to see what would happen. Couldn't do it, because it would just round up and into the wind once the rudders started working more like elevators than rudders. We probably only had one rudder in the water at that point anyway, and with full opposite wheel it couldn't stop the roundup once it started. The water was warm, the shore was swimming distance even in the waves, and PFDs securely on, of course.

The only thing that really worries me when my family is on board is an accidental keel drop. When we want to get somewhere fast, I always resist the temptation to drop the ballast when they are on board.

Okay good to know - and I think the dogs in the US are fatter too - (AND the people!)

I am still intrigued by the "sailing on it's side" comments I read on all the boats - I can only comment on my experience with 'boat' which is an M boat - I can lay the boat over rather easily - it does not take a lot of wind to put the boat over past 45 degrees - if I have all the sail out and I put it hard against the wind it will go over without much trouble - and I can sail pretty good like that - the boat steers fine - holds a course, and scoots along pretty well - there is really not a huge loss of speed - now, if I relax the sheets and let the boat sit a little taller it does indeed go a little faster, but I really have no trouble at all controlling the boat at 50 degrees - it sails just fine.

This was a surprise for me when I got the boat - because my previous trailer boat (A23) would not steer at those angles and would often stall. (Actually, MOST boats will stall out at 50 degrees).

It's not that I spend all day sailing at 50 degrees, it's just that reaching a heel angle of 50 is not a huge event aboard 'boat' - it's usually only a temporary thing that only lasts a few seconds and nothing dramatic happens. I hear the same experiences from Highlander and Beene and mastreb and NEO and other M drivers and I guess I am confused why it's an issue for some and not an issue for others and I just happen to notice the difference seems to be depending on what boat your on. Is there anyone out there that has sailed both?

Tomfoolery wrote:


.

Nice graphic that illustrates the problem very well. No boat has its centre of mass exactly on the centreline. Most X's have a slight list to one side or the other to begin with, and if a few more of the passengers were on the heavy side, that could easily shift the centre of mass what, a couple of feet? What happens to the graphic if the centre of maas is two feet farther toward to low side? The death roll could start at a really shallow angle, easily achieved by a keel-down power turn.

Just for fun, I moved the sailboat's CoM to the starboard by one foot.



Above are the first images from before (repeated below), but with the CoM moved off-center. It's already beyond the angle of vanishing stability at 15 degrees of heel. I scraped off the last image (40 deg. of heel), as it was unnecessary, with 15 deg. of heel being beyond the AVS already.



That's not to say a group on the cabin roof moving to one side will heel the boat beyond the AVS, but rather, the AVS seems to be greatly reduced by moving the 'ballast' off-center. Which, of course, makes sense, and is the reason crews will do the rail meat thing on the windward side.

Moving 1400 lb of people 3 ft off-center will put the whole boat's center of mass about 1 ft off-center, assuming a bunch of things (2600 lb boat with no ballast, boat's CoM centered to start, and so on). And having that 1400 lb of people high and off-center seems to have rather drastic effects.

That's just a cartoon sketch, of course, which I did just to see what it looked like. I have no idea what the actual angles would be, as that's dependent on the hull shape and actual location of the empty boat center of mass.

But I'm surprised (and not surprised, at the same time) at how much of a detrimental effect a lot of people on the cabin roof can have, even if they don't move off-center. And people 'off-center' can simply mean half are at the rail, and the other half are on the centerline. And standing, hanging onto the mast, makes it worse (raises the CoM). A wake, wave, some engine thrust, a rudder sticking straight out the back in a wake or wave, or the CB down in a turn could conceivably be all it took to send it beyond the point of no return.

Something that just occurred to me is when we were moving building modules by barge (up to 720 tons each), the naval architects and surveyors were very concerned about sea state. What they considered stable in calmer waters was too close to the danger point in rougher waters. We had to spend a LOT of money cutting holes in the barge decks and removing the coamings of many in order to lower the load to where they felt confident in signing-off on the barge/load combinations. And even more to put them back together after the work was done. The modules had to be located port-starboard within an inch or so of designed position, based on the calculated location of their centers of mass. Which wasn't quite right on any of them, as the concrete floors are never as perfect as they are on paper. Oh, and you can see the 'inkwell', where the ants are milling about, cut into the barge to accept the so-called Y-column, in order to keep the load low.

I wasn't privy to the negotiations (my part was in lifting them, not barging them), but it was interesting to hear the bits and pieces that came out on conference calls. The take-away of that is, of course, dynamics also play a big part in vessel stability. What's ok in calm conditions can be far from ok in waves, wakes, rollers, wind, whatever.

Talk about top-heavy.

I was watching the crab boats on one of those adventure channels the other day - "Deadly Catch" or something like that - can't remember but they were up in Alaska - and I guess when they have all their fishing pots (traps?) on top of their boat it makes them unstable - who would've thought? Anyways, I think your theory about the slight balance shift to one side sounds like a plausible cause - the numbers make sense based on your chart.

Anyways,

Tom, I think we need to get these GZ curves filled out for the X boat - I can't find any data on the web:



It seems there is tons of data if you own a Contessa 32 but I can't find anything on the X boat - you see that little bump on the top of the Bavaria 32 chart? That is the nasty "feel" you get when the boat suddenly accelerates it's heel and then get's legs again at a steeper angle - this is very common on a lot of boats and is mostly due to hull shape.



I know the M boat actually has an improving curve at 50 degrees and you can even extend and flatten out the top of this curve on the M because it actually gets stiffer as it approaches 90 degrees - some boats have a very smooth curve so the sensations is not so jarring - my old A23 had a very round bottom and a very smooth GZ curve but even with that smooth curve the boat stalled at 50 degrees.



I can't find even scant data on the X - mastreb did get some info from somewhere once on the M but I can't remember where he got it.

Is there a place where there would be data for this for MAC boats?

Well, we have one data point:

https://www.youtube.com/watch?v=5jNkkz8Xop0

Jump to 2:40. If we believe what Roger says, that's 120lbs about 90% of the way up the mast, with the ballast full. I suppose someone (Tom!) could make an estimate of the location of the ballast and take a swing at the righting moment with the ballast out. Might we find negative stability at 90 degrees with an empty boat and no ballast?

You can't do this on the M boat - I can tell you that - the M boat will lean over way more if you do this on the M boat when the ballast is empty - 'boat' is VERY tippy at the dock - I know because I always launch with the ballast empty and the valve closed - When I first step on the boat it leans WAY over - (Am I just too fat?) maybe - but I can tell from this picture that the X boat is a LOT more stable than the M boat - the X boat leans over a lot less than the M would in the same situation:



If you did this on my boat with no ballast in the boat would be leaning over pretty far - it would no way be as flat as the boat in this picture.

'boat'would lean over a good foot by just me stepping in. It's obvious to me that the X sails a LOT flatter than the M does based on what I saw in that video.

Thats my experience with the X it hardly moves when I step on before filling the tanks and Im no feather weight (90Kg or 200lbs)

Look at the photo carefully notice the scallops in the captains seat, mine is real early production and doesnt have those, so I presume that may be a prototype in the picture