Capsize Angle

[kurz]

Hey Guys,

Appreciate the input on the question of capsize angle.

...
Does anyone know if technical data exists what the capsize angle would be if the ballast was empty on either a 26M or 26x? This would be with the mast on, sails down.

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Thanks, Ed

See #1, the manual says 60 degrees.

[NiceAft]

Kurz,

Before sending my previous post, I looked through the two manuals in our resource section. There is much information and easy to miss a particular fact in a search of the pages, and I must have missed it. This is of interest to me. Which manual was 60 degrees in, and what page.

Thanks.

[Starscream]

Not a helpful comment on Macgregors, but I just watched a youtube video by Practical Sailor on the capsize of the superyacht Bayesian. It had a centerboard weighted with 90,000 lbs of ballast! The crew kept the centerboard in the up position at anchor, because it would bang around just like our little Mac-Centerboards.

The Bayesian had an angle of vanishing stability of just 88 degrees with the board down, and only 77 degrees with the board up. Even worse, it had a down-flooding angle of 45 degrees, and likely had open ports and doors that let water flood in as it heeled over during the downburst.

A horrible affair, with 7 deaths. But somehow I find relevance to our little boats in this tragedy.

[kurz]

Kurz,

Before sending my previous post, I looked through the two manuals in our resource section. There is much information and easy to miss a particular fact in a search of the pages, and I must have missed it. This is of interest to me. Which manual was 60 degrees in, and what page.

Thanks.

[NiceAft]

Thanks Kurz.

When I reread the the manual (twice), all I saw was:


I did not pay attention to the second column on the page.



Under stability, it says this:


I’m sure most of us have missed this; thanks for pointing this out. Now I’m even more sure that sailing without the ballast full is not a smart thing to do. One never knows when that unexpected blow can come. There are times when I have done it, but they are very few.

By the way, I looked up the Manual.

[Jimmyt]

Capsize with full ballast would be the angles at which water could gain access to an open fwd hatch or cabin entry companionway. The challenge is as sail loading increases the heel angle also increases which shed wind load

I assume he’s actually referring to the AVS, or angle of vanishing stability; where the boat is no longer self-righting.

You are getting into down-flooding angle, which is another critical piece of information - the angle which the boat begins to take on water.

The AVS is 60 for a stock M UNDER A SPECIFIC LOADING (your boat may differ). With ballast full (and boat empty), you are good to at least 90 degrees, and likely beyond (watch the propaganda video from Roger).

If you don’t remove the flotation foam or pack the boat full of lead/acid batteries, etc, it won’t go straight to the bottom if you find yourself exceeding the AVS, or down flooding angle.

[OverEasy]

THANK YOU Kurz, NiceAft & JimmyT for researching and sharing this info!
Both for the Mac26X and Mac26M!

The aspect of angle of vanishing stability (AVS) is something I got to experience first hand twice yesterday…..
Nothing dramatic, only good fun, when my younger daughter (now 24 … sheeze time flyby) want me to go out on our little Sunfish yesterday. There is only just so much wind in the sail before the speed vs angle ratio means a swimming lesson and righting drill!
(My problem is I’m not as spry as she is and it’s a bit of an entertaining side show watching me get back on board )


Best Regards,
Over Easy

[NiceAft]

My problem is I’m not as spry as she is and it’s a bit of an entertaining side show watching me get back on board

Been there, done that, many times; part of the fun of those sailing dinghy’s .

Me about thirty



Me, many, many decades later.