So what went wrong???

in the same plane that the stability was calculated..
sycrolift/travellift even sideways as many new vessels are launched not a boat ramp/slipway, that keep generating good photos

 

In answer to the question, "What went wrong," I guess putting it in the water was probably the biggest mistake.

Poida

 

wrong density water?

 

Slipways are cheaper, and there's absolutely no reason for a competent NA/yard not to be able to launch them safely on a slipway every time.

There's also no reason that a longitudinal launch can't be safe - it's just another set of calculations.

Someone in this case did something stupid - much MUCH more likely than being the launch method's fault..
My money is on not enough ballast.

 

Yeah. I'm guessing she could have been insured for that much.

On a hopefully unrelated note, because I thought of it before I read your post, thing about the video in post #2 that I noticed was something about the paint job, the underside was kinda blotchy, which I guess wouldn't be seen after launch, but the company logo on her bow also seemed rough on the port side which is not something I would expect on such an expensive yacht. It may just be a panel not tightened down yet. This is clearest right at the end of the video but can also be seen before then too.

Again, I'm not suggesting anything is amiss besides the launching. Just relating something I noticed earlier.

 

At the time of the video it wasn't finished, it was a short recap of getting to that point.

 

yes but I can tell you that many vessels cannot be slip launched as they have no stability during the slipping ( half floating) or they need to do a one off ballasting job
I have had NA buddies tell me this when doing the calculations
if you can throw it in fast enough you get over the issue but you are not doing that with a 50m vessel backwards...
evidence shows 2 facts,
a travel lift/sycrolift can safely launch anything
not every vessel can be slip launched, photos prove it

 

One of the things that struck me when I saw this video about a week ago is that this motoryacht has very little draft, especially compared to her topsides height and height of superstructure. To me, she looks top heavy, plain and simple.

Eric

 

Like Dolly Parton in a miniskirt.

 

It doesn't seem there is enough below water volume where it would float at it's intended waterline.

The narrow windows that the crew crawled out of...is it common to have windows so close to the waterline?

 

Given how they were moving her around in the you-tube video, she looked pretty light, which is to be expected for a modern yacht. I bet they had a A-1 launching weight limit to hit for the launching equipment and her stability was wet ballast driven. So while ballasting down they lost waterplane, just like the COUGAR ACE and ROCKNES. As has been pointed out in several recent threads, most stability programs don't automaticly find transient flood up conditions where you have no stability...you have to go looking for them.

 

Some shipyards and designers do put windows between the sheer and the waterline, and of course, the closer they are to the waterline, the more serious are the concerns. Ideally, they should not be opening ports. If they are opening ports, then they should be fitted with watertight deadlights.

Eric

 

That's what I thought. To be stable there would need to be so much weight down low the average density of the volume below the waterline would have to be about the density of water -but that can't be because the huge upper has some weight. As dopey as the shallow draft and towering topsides look, think about how this boat would float lightship! The design waterline looks insanely shallow and it was floated without all the fuel and water to put it at that line. This doesn't look like a luxury boat, it looks like a cartoon! If it runs low on fuel does it roll over and sink?

I just can't understand going so vertical on such an expensive boat. Why wouldn't you prefer to go longer and lower?

 

Actually, she looks very typical in proportion to other successful Northern Marine vessels, yachts and fishing vessels. The only thing that seems strange is her tankage, stated as 11,000 gals ~82 Klbs, which is a lot for her displacement, ~281 Klbs, 130 LT (which seems light...see my edit <shrug>).

Other builds by this company are here.... http://www.northernmarine.com/lrcs.php?sm=lrc

Edit to add, the hull is #8501 "Baden' (ex Blood Baron...as if that is an auspicious name...) More info here... http://yachtcaptainblog.com/

 

You would think. In fact, Steve Dashew has capitalized on that beginning with his Deerfoot designs, and later with his long, lean powerboat designs. However, the cost of yacht maintenance and upkeep is directly proportional to lenght (think haulouts, docking fees, etc.) and that right there is an incentive to go wide and tall rather than long. Also, elbow room (beam) is very desirable, but you can increase that only to a certain amount before you run into fuel cost issues--fat boats consume more fuel than narrow boats. That leaves height--high ceilings (bigger tween deck spacing) feel better to the psyche than low ceilings. Higher tween decks mean taller windows, and taller windows let in more light than shorter windows. They also give a better view of the outside from the inside. Finally, being up high on the upper decks is more desirable to the psyche than being down low. Finally, going tall is actually cheaper to build than going long and going wide. So there are a number of marketing pressures that seem to force some of these yacht designs to be top heavy.

That's my take on the situation.

Eric